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News – New Metrohm Autolab instruments, new Coulometer, and new Optrode sensor

Customer application – Hot chemistry: quality control of radio pharmaceuticals using IC

Practical Tips – Determine hexavalent chromium conforming to U.S. EPA method 218.7

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INFORMATION

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Editorial

It made ion chromatography affordable for many analytical sectors where previously any thought of purchasing an IC had been totally out of the question. Furthermore, as its name indicates, it is uniquely compact. The 761 does away with unnecessary peripherals such as a gas supply and relies on robust «MSM» suppressor technology that is backed up by a 10-year warranty. With the outstanding quality of its measurement results, the 761 Compact IC transformed the world of ion chromatography.

Now that routine analysis is under control, the requirements are increasing: trace analysis, concentrations at ppt and sub-ppt levels, difficult matrices, large differences in concentration, high sample throughput, FDA 21 CFR Part 11 compliance and client-server installations, to mention just a few. With the 800 series and today with the «Metrohm Professional IC» line, Metrohm is always right at the forefront in the further development of ion chromatography: Eluent preparation is fully automatic, the times of manual sample preparation are gone, calibrations over six orders of magnitude can be performed easily with just one standard, .... A large range of separation columns with different materials for each application, various detectors (conductivity, amperometry, UV/Vis), and combi-nation with other analytical methods (titration, pH and conductivity measurement, MS, ICP-MS, digestion) underline Metrohm‘s position as a leading innovator in ion chromatography. However, 25 years is just a milestone, as development continues!

And this applies not only to ion chromatography, but also to titration. You will find two new products in this issue of Metrohm Information: the 899 Coulometer and the Optrode.

Dear Readers,

Today we have something to celebrate: 25 years of Metrohm IC – a quarter century of ion chromatography! What was launched as a single instrument in 1987 has now developed into a veritable group of products that is second to none: state-of-the-art, groundbreaking in sample preparation, unbeaten in ease of use, robust, cost-effective and, at the same time, very precise and accurate.

Compared with pH measurement and titration, ion chromato-graphy is quite a new technology. The first work on this topic was published by Small, Stevens and Baumann in 1975. Ion chromato-graphs were expensive and bulky. The development of separating materials (ion exchange materials) was in its infancy. Initially, this technology was the preserve of enthusiasts who either had lots of money for instruments and suppressors or who were completely tired of the wet chemical methods for determining anions and cations – so much for the separation processes learnt in the basic laboratory courses.

But development continued and crucial technological progress was made with Metrohm’s 690 Ion Chromatograph. The 690 was the first IC that was based on single-column technique and therefore did not require chemical suppression. The key here was a highly sensitive conductivity detector. And still today the Metrohm detector is the best on the market.

With the 700 series, Metrohm continued to extend the product range with more automation, sample preparation and electronic data processing. But the most important step came in 1999 with the introduction of the 761 Compact IC, and there were several reasons for this: the 761 was the first really cost-effective ion chromatograph.

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The 899 Coulometer is a very compact Karl Fischer titrator that is offered to you by Metrohm. It can be operated easily and without a computer, has an innovative autostart function and provides the pos-sibility of data export via an Ethernet connection. If you would like to perform measurements on the move far away from a 220 V power supply, the optional power pack for the 899 Coulometer gives you the independence you need for a large number of determinations!

If one visits our subsidiary Metroglas, where all Metrohm’s glass electrodes are made exclusively, one enters a world where traditional glassblowing skills are combined with high technology and state-of-the-art production methods. Gold and silver are «fused» with glass and highly integrated thick-film circuits to form electrodes. The latest development is the Optrode: a sensor with an inert glass shaft for photometric titration that has LEDs with eight different individual wavelengths from 470 to 660 nm.

At this point, I would like to thank you for the numerous re sponses to our reader survey. You will find the results in this magazine. Despite e-mail, the Internet and new media, the tradi-tional, conservatively printed Metrohm Information remains an established component of our extensive documentation for you, as it has for 41 years already.

Enjoy your reading.Dr. Kai Henning ViehwegerDirector and Head of Sales and Marketing in the Metrohm Group

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InhaltInhaltsverzeichnis

Table of contents

Editorial• Metrohm celebrates 25 years of ion chromatography 02

Anniversary•A look back at 25 years of Metrohm ion chromatography 05

News• 899 Coulometer – affordable coulometric KF titrations also off grid 09• Optrode – sensor for photometric equivalence point determinations 10• New version of the Aquatrode plus & ionselective ammonia electrodes 12• New electrochemical analyzers from Metrohm Autolab 14

Results of the Metrohm Information Reader Survey 16

Customer application report• Radio ion chromatography for quality control in PET diagnostics 18

Practical tips• Determine hexavalent chromium conforming to U.S. EPA method 218.7 24

Application literature• New Metrohm Application Notes and Application Bulletins 26

New: further applications & electronic editionThe electronic edition of our customer magazine Metrohm

Information and the archive with all editions from 2005 to 2012 is available on www.metrohm.info. There you will also find our newest literature references as well as further information on appli-cations for downloading.


0525 years of Metrohm ion chromatography

Metrohm is a well-established company in the field of ion analysis. Back in 1948, it manufactured the first pH meter. Not quite so long ago, Metrohm also moved into ion chromatography. The achievements of Metrohm in its services to users are all the more important: thanks to Metrohm, any user can perform ion chromatographic analyses successfully! Below, you will find a brief history of how things started and what has happened since then.

The first Metrohm ion chromatographFollowing the successful launch of its own electrochemical

HPLC detector in 1981, Metrohm started developing a conductivity detector in 1983. Very soon the development team realized that this task was achievable, but there was still a lot more to it: in order to obtain a stable baseline and low detection limits, the entire analytical system from the high-pressure pump and the capillaries through

The first Metrohm ion chromatograph: the 690 Ion Chromatograph

to the separation column had to be optimized. In 1987, Metrohm presented its first ion chromatograph, the «690 Ion Chromatograph». This innovative instrument combined an injector (manual sample injection), separation column, detector and control electronics in a single housing and relied on single-column ion chromatography with electronic suppression. In this way, Metrohm proved that ion chromatography (IC) can be successful even without chemical suppression. For better or worse, a decision had to be made in favor of electronic suppression, because chemical suppression was at that time protected by patents and therefore not available. Although originally a hurdle, this might be precisely the reason why Metrohm’s conductivity detector is still today the best on the market: to be able to detect the smallest changes in conductivity successfully on a high background, one needs to go to the limits of what is possible and make no compromises – this was achieved impressively.

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Why use ion chromatography at all?IC offered crucial advantages over photometry, which was

widely used at that time: with IC it was possible, for example, to analyze a sample consisting of seven different anions within a few minutes, whereas photometry took hours to determine just a single anion! Metrohm grabbed the opportunity to open up new sectors of the market and moved into IC, which from then on constituted its second core activity alongside titration.

The first modular Metrohm ion chromatographIn 1996, with the 700 series, Metrohm presented a modular

ion chromatograph that had a lasting effect on IC. The simplest configuration consisted of a 709 IC Pump, 732 IC Detector (conduc-tivity detector) and 733 IC Separation Center with permanently fitted Metrohm Suppressor Module «MSM». In the meantime, Metrohm had gained access to chemical suppression and now combined this with its outstanding conductivity detector – thanks to an excellent signal-to-noise ratio, the lowest detection limits were achievable.

As an optional two-channel instrument, the modular ion chro-matograph could be used for simultaneous determination of cations and anions. The integration of numerous extension modules opened

up new applications and made the user’s work easier: many of the tasks that had previously been done manually were automated − with positive effects also on reproducibility. With one of the first extension modules, the 754 Dialysis Unit, it was possible to separate matrix consisting of suspended matter and solids as well as extremely fine particles, proteins and fats by means of dialysis. This made it possible to analyze fruit juices, soil samples, slurries etc. with ion chromatography without risking blockage of the separation column or a shorter column life.

Compact, versatile and economical – the 761 Compact ICIn 1999, Metrohm brought a groundbreaking product on the

market in the form of the 761 Compact IC. The first compact ion chromatograph combined a maximum amount of IC (injection valve, double-piston pump, Metrohm Suppressor Module, high-perfor-mance detector, peristaltic pump, electronics for data processing and a variety of separation columns) in minimum space. It was as efficient as the modular ion chromatograph and also produced top-quality analytical results – at an extremely attractive price. The 761 Compact IC was followed by other compact instruments, such as the 790 Personal IC and the 792 Basic IC. These, too, provided the user with uncompromising data security and outstanding accuracy of results with extremely low detection limits.

Metrohm’s first modular ion chromatography system with the 733 IC Separation Center.

With the 761 Compact IC, anyone can afford ion chromatography.

Anniversary


The modular Advanced Ion ChromatographsFor Metrohm, the focus in 2003 was on the modular «Advanced

Ion Chromatographs». Existing modules and the software were modifi ed for the Advanced series and upgraded with many optimiza-tions and extensions, such as a permanently fi tted column oven and the CO

2 suppressor. Liquid handling, sample preparation techniques

and also automation of analysis were developed further.

Intelligent Metrohm ion chromatography sets new standards

New standards in IC were set by Metrohm in 2007 with intelli-gent ion chromatography and the introduction of the ion chromato-graph 850 Professional IC, iColumns (intelligent separation columns), 858 Professional Sample Processor (versatile sample changer), 872 Extension Modules and MagIC Net™ (new control and data acquisi-tion software).

The outstanding features of Metrohm’s intelligent ion chroma-tography are the intelligent and innovative components (iPump, iColumn, iDetector, Dosino 800 and MagIC Net™) that are incorpora-ted in the 850 Professional IC. They enable comprehensive, automatic monitoring and optimization of all system parameters and complete documentation in accordance with GLP and FDA regulations. The IC system is able to make logical decisions independently (e.g. during sample preparation) and offers very easy operation even of complex procedures. This leads to a maximum level of reliability and excellent analytical results. The intelligent Metrohm ion chromatographs offer

all possibilities of modern IC: comprehensive automation possibilities including fully automatic sample preparation, a variety of detectors (conductivity detector, 887 Professional UV/VIS Detector, 896 Profes-sional Detector – Amperometry) and numerous extension modules to choose from, hyphenated techniques, microbore technology, ….

The same properties are also to be found in the compact intelli-gent ion chromatographs 881 Compact IC pro and 882 Compact IC plus that appeared in 2008 – again with a further reduced footprint and at a very attractive price.

What makes Metrohm ion chromatography so successful?The success of Metrohm IC is based on the interplay of several

factors that ultimately make the user’s day-to-day work more effec-tive and more enjoyable. Metrohm instruments are characterized by their ease of use as well as multi-language user interfaces and opera-ting instructions. A great deal of manual work is eliminated by using «Metrohm Inline Sample Preparation» (MISP) − which includes Inline Ultrafi ltration, Inline Dilution, Inline Preconcentration, Inline Calibra-tion, Inline Spiking etc. − and with the help of numerous automation solutions. The combination of sample preconcentration/dilution and matrix elimination (Metrohm intelligent Preconcentration Technique with Matrix Elimination, MiPCT-ME) enables automatic ion chroma-tographic analyses to be performed over six orders of magnitude. If a sample is outside the calibration range, because, for example, its concentration is too high, then it is diluted and reanalyzed automati-cally without any action on the part of the user – uniquely practical!

The intelligent 850 Professional IC is extremely fl exible and offers all the conceivable possibilities of modern IC.

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A worldwide network of distributors and subsidiaries provides application support and offers seminars and training. Our application literature (monographs, Application Bulletins, Application Notes, posters and technical articles) is available free of charge and can for the most part be downloaded directly from www.metrohm.com.

Metrohm stands for high-quality, robust instruments and soft-ware that is «Made in Switzerland» and state of the art. Users of our products are able to achieve extremely low detection limits and obtain extremely accurate analytical results with guaranteed data security. Numerous coupled techniques such as IC-MS and IC-ICP-MS also make it possible to analyze samples that are difficult to separate. Metrohm’s long experience in ion analysis enables ion chromato-graphy, titration and direct measurements to be fused together in a compact, tailor-made unit: the TitrIC systems for water analysis are the best example of this.

Users trust Metrohm technology and they have good reason to do so: we offer a three-year warranty on all our instruments. The numerous Metrohm Suppressor Modules even carry a ten-year warranty − much longer than the usual warranties available on the market. Because we guarantee that spare parts will be available for

all instruments ten years after an instrument was last produced, any investment will be well protected. Compared with competitors’ products, the operating and maintenance costs of Metrohm ion chromatographs are extremely low! This is evident, for example, in ultrafiltration, where Metrohm relies on membrane technology instead of on expensive disposable filters.

A happy workforce as a guarantee of successThe workforce at Metrohm is also a very important success

factor – the Swiss manufacturer of analytical instruments offers its employees a secure job and a good working environment. A happy workforce provides an exceptional service that can be nothing other than a benefit to our customers.

Another important element of work is that one enjoys doing it and always remains good-humored. Many readers will be familiar with Ricola, a brand of herb drops from Switzerland that is known around the world with the unmistakable advertising slogan «Who invented it? The Swiss, of course!» This does not apply to the origins of ion chromatography – but what is much more important for the user is the question of who made ion chromatography accessible to everyone by providing innovative and economical instruments: «The Swiss, of course!»

The various MISP sample preparation techniques also include Inline Ultrafiltration and Inline Dialysis.

Anniversary


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899 Coulometer – ideal for taking with you!

The new 899 Coulometer is the smallest and most compact Metrohm coulometer to date. By using the optional battery pack, you no longer have to depend on mains power. Take with you your 899 Coulometer and do your water content determinations wherever you want!

The 899 Coulometer is already equipped with a magnetic stirrer, thus you no longer need to connect an external stirrer and have more space free on your laboratory bench. However, if you wish to connect another stirrer (e.g. the 803 Ti Stand with built-in pump), you can do so at any time.

The integral titration cell holder fixes the titration cell securely on the top of the 899 Coulometer, so there is no need for a support rod.

The new coulometer impresses not only with its compactness and its small footprint, but also with its outstanding flexibility. If the instrument is also to be used outside the laboratory, an optional battery pack is available for the coulometer. This battery pack ensures independence. Regardless of whether there is a connection to mains power available or not, you can carry out your water content deter-minations wherever you want with the coulometer.

The 899 Coulometer is also suitable for determining trace amounts of water in plastics.

For analyzing difficult samples (poor solubility of samples, secondary reactions with reagents, release of water only at higher temperatures, etc.) the 899 Coulometer can also be operated in combination with one of our KF ovens. Both with a manual oven (860 KF Thermoprep) and with an automated oven system (885 Compact Oven Sample Changer), the Coulometer forms a perfectly matched team that will determine the water content of your samples reliably.

10 Optrode – the new photometric sensor

The new Optrode photometric sensor offers many advantages for photometric titration like a completely solvent-resistant glass shaft and enables you to always choose the right wavelength for your measurements. Another benefit of the new sensor is the easy integration even into new and existing automated titration systems.

Titration with a photometric sensor is a widely used titration technique. It is based on color changes at the equivalence point and is especially helpful when

• the potentiometric determination of the equivalence point is not possible,• no suitable potentiometric electrodes are available,• an official method prescribes photometric indication,• the output signal of a potentiometric electrode is influenced

by matrix effects,

• the price advantage of titration over more expensive techniques (e.g., AAS or ICP-AES) is used,• easy and quick performance of the measurements is considered

important,• or the end point of a manual titration no longer should be

determined visually.

With the new Optrode, the advantages of photometric titration can be used to optimum effect. Eight wavelengths (470, 502, 520, 574, 590, 610, 640, and 660 nm) are available, so the optimum wavelength can always be selected for the particular application.

Because of the glass shaft, the Optrode is 100 % resistant to solvents and therefore ideally suited for use in organic solvents. Furthermore, the glass surface is easy to clean.

News

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The Optrode is suitable for photometric equivalence point determination in aqueous and nonaqueous acid-base titrations, pre-cipitation titrations, complexometric titrations, and redox titrations.

Application examples:• photometric titrations according to USP and Ph. Eur. (nonaqueous) • determination of the carboxyl end groups (nonaqueous) • TAN/TBN according to ASTM D974 (nonaqueous)• chloride in silicone products (nonaqueous)• sulfate determination• Fe, Al, Ca in cement• water hardness (total hardness and Ca/Mg)• chondroitin sulfate according to USP 34

The very compact Optrode (article number 6.1115.000) is no bigger than a pH sensor and can therefore be integrated without problem in the titration head of a sample changer. It is easy to use because it can be connected to the titrator like a potentiometric sensor. Both new and existing titration systems can be equipped with the Optrode. Power is supplied via the USB port of a Metrohm instrument (Titrino plus, Ti-Touch, Titrando, USB sample changer). In the case of older models, the power can also be supplied via an optional USB power adapter.

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News about Metrohm electrodes

Aquatrode plus with Pt1000 temperature sensor and detachable cable

The proven Aquatrode plus is especially suitable for pH measure-ments and titrations in low-ion and poorly buffered samples, such as surface waters and deionized water.

The major benefits of the Aquatrode plus are:• Special membrane glass for measurements in low-ion solutions.

This guarantees very short response times even in these difficult samples and makes a fast measurement or endpoint titration possible.• Fixed ground-joint diaphragm with very low, clearly defined

electrolyte flow for very accurate and reproducible pH measurements or titrations.• Clever double-junction design with maintenance-free inner

electrolyte (gel) and replaceable bridge electrolyte that enables the Aquatrode plus to be adapted to the measurement conditions.

The Aquatrode plus is available in a number of variants: with and without Pt1000 temperature sensor, with different shaft lengths, and as intelligent iAquatrode plus. The latest variant of the Aquatrode plus (article number 6.0257.600) offers all the above benefits plus an additional one: the detachable electrode cable. The electrode with integrated temperature sensor can now be stored separately from the cable and replaced independently, offering the user more flexibility.

Ammonia electrode with replaceable modules/membranesTo determine the concentration of ammonium with the help

of an ion-selective electrode, the ammonium ions in the sample are converted into ammonia through the addition of NaOH solution. The ammonia then diffuses through the gas-permeable membrane of the ion-selective NH

3 electrode and is detected by means of an inner

combined pH electrode. The membrane is a consumable item that can be replaced easily and conveniently. Depending on the appli-cation, the following options are available:

News


No matter whether your samples have a high or low concentration of ammonium: with the two versions of the NH3-ISE you can always

select the appropriate electrode. Because the inner pH part of the sensor is identical in the two versions, the nature of the sensor can be changed easily at a later date with the relevant replacement kit.

NH3-ISE (Low)

• For cleaner samples (e.g., drinking water, boiler feed water, mineral water)• Faster response time close to the detection limit• Lower detection limit• Easy, safe replacement of the complete module• Preassembled, individually tested and certified complete modules • Article numbers: NH

3-ISE (Low) (6.0506.100), Replacement Kit for

NH3-ISE (6.1255.000)

NH3-ISE (High)

• For wastewater samples• Long-term measurements, monitoring• Faster regeneration time after high concentrations • Better signal stability at high concentrations • The best results at all times (e.g., even with wastewater

samples that contain oil) as only the membrane needs to be replaced• Economical replacement of only the membrane • Article numbers: NH

3-ISE (High) (6.0506.150), NH

3

Replacement Kit Membrane (6.1255.050)

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14 New electrochemical analyzers from Metrohm Autolab

This year, Metrohm Autolab is again launching some interesting new instruments in the form of the versatile FRA32M electrochemical impedance analyzer module, the modular Multi Autolab multi-channel measuring instrument, and the further-developed PGSTAT302F potentiostat.

With its wide-ranging product portfolio, Metrohm Autolab, Metrohm’s Dutch subsidiary, is one of the world’s leading manufac-turers of electrochemical analyzers for research. In accordance with the motto «Dedicated to Research» Metrohm Autolab not only sells measuring instruments, but also fosters close contact with customers and offers a comprehensive service, ranging from the construction of customized instruments and maintenance work through to customer training.

Electrochemical impedance analyzer moduleElectrochemical impedance spectroscopy (EIS) is one of the

most important techniques for electrochemical analysis and is used

routinely in electrochemistry and materials research, wherever the examination and evaluation of material or system properties are in-volved; for example, in the characterization of batteries, biosensors, fuel cells, and semiconductors. With EIS it is possible to make state-ments about the dynamic behavior of an electrochemical system, and EIS provides a unique insight into the processes that occur at electrochemical interfaces (e.g., the electrode surface). Typical uses include investigations into the mechanisms of coating processes (electrodeposition and electrodissolution), diffusion of ions across membranes, and also passivity and corrosion studies.

Metrohm Autolab’s state-of-the-art FRA32M electrochemical impedance analyzer module can be used to complement and upgrade both existing and new modular instruments from Metrohm Autolab and also instruments in the new Multi Autolab product line. The FRA32M module for EIS can generate and process single-sine and multi-sine excitation signals up to a maximum frequency of 32 MHz (up to a maximum of 1 MHz when used in combination with a PGSTAT).

The Multi Autolab/M101 housing the M101 potentiostat/galvanostat moduls can be adapted to customers’ requirements with a series of additional modules.

FRA32M module for electrochemical impedance spectroscopy (EIS).

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Metrohm Autolab is extending its portfolio with new products such as the modular Multi Autolab instrument.

Multi Autolab – the new modular multi-channel measuring instrument

Following the extremely successful launch of the PGSTAT101 entry-level potentiostat/galvanostat, Metrohm Autolab is now glad to present the Multi Autolab/M101, the further-developed multi-channel version of the PGSTAT101 (10 V/100 mA). The Multi Autolab can be fitted with up to twelve M101 potentiostat/galvano-stat modules, each with completely independent software control. Alternatively, a companion module (e.g., a FRA32M electrochemical impedance analyzer module) can be installed alongside each M101 module, until the maximum number of 12 modules overall has been reached. The possibility of combining the potentiostat/galvanostat modules with other additional modules provides maximum flexibility and the Multi Autolab can be customized to fit the experimental requirements and customers’ wishes in the most effective way.

The following (additional) modules are available for fitting to a Multi Autolab:• M101 potentiostat/galvanostat module• FRA32M electrochemical impedance analyzer module• EQCM electrochemical quartz crystal microbalance module• BA dual-mode bipotentiostat module• pX1000 pH and temperature measurement module • MUX multiplexer module

PGSTAT302F – Potentiostat with optional floating capabilityThe new PGSTAT302F potentiostat completes Metrohm

Autolab’s PGSTAT product line. It is based on the PGSTAT302N and therefore has very similar specifications, but offers more application possibilities on account of its optional floating connections. The PGSTAT302F can be switched between «floating» and «normal» modes. The normal mode can be used with regular electrochemical cells, while the floating mode can be used in combination with electrochemical cells directly connected to ground or with working electrodes connected to ground (e.g., pipelines or autoclaves).

Further details of the full range of Metrohm Autolab products can be found on the website www.metrohm-autolab.com.

The new PGSTAT302F potentiostat with optional floating connections.

16 Results of the Reader Survey 2011

The very pleasing results of the Metrohm Information Reader Survey 2011 are now available: our customer magazine was judged to be very informative, useful and of high quality. We would like to thank the many respondents for filling out the online questionnaire. You have made an important contribution to the ongoing task of making our customer magazine even better.

Time is a valuable commodity. We are very appreciative of the fact that a large number of readers took time out for us and provided us with many replies to open questions. The survey shows a very positive picture of Metrohm Information. We are pleased to report that we received replies from all parts of the globe. Our readers are mainly users, laboratory personnel, and laboratory managers from sectors such as general chemistry, contract laboratories, water, air, environment, pharmaceutical, education, foods, organic chemistry, biofuels, and petrochemicals.

Exceptionally high level of satisfaction among our readersThe vast majority of respondents regard our magazine to be of

high quality. This applies both to the external (physical) appearance and internal ratings (ease of reading, high information content,

practical value, etc.). More than 85 % are satisfied or very satisfied with Metrohm Information; a mere 4 % would not recommend it to others. All topics from new products through to new publications were well received or very well received. There was special interest in reports on analytical methods and applications and on practical tips. Titration, pH and conductivity measurements, and ion chroma-tography were at the forefront. The length of the individual articles and the overall size of Metrohm Information were judged by a large majority to be ideal. We endeavor to convey information to you briefly and succinctly, though from time to time we provide a more in-depth insight into, for example, an analytical method. For us it is always a special challenge to present you with a good mix of topics with information from all our areas of ion analysis – 80 % are pleased or very pleased with the mixture of topics.

Great need for well-founded informationOur readers would like to be supplied with news at least two

or even three times a year. Do you already know the web page of Metrohm Information www.metrohm.info or our newsletters regar-ding titration and ion chromatography? You can sign up for the latter directly on our homepage www.metrohm.com. The newsletters will be sent to you by e-mail approximately once a month.

13 %

74 %

13 %

0 % 0 %

Very satisfied SatisfiedNeither satisfied nor dissatisfied DissatisfiedVery dissatisfied

Overall satisfaction withMetrohm Information

46 %

36 %

18 %

Paper versionElectronic versionBoth, paper version and electronic version

Preferred type ofpublication

Reader Survey

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Print is still far from «dead»Do our readers still want a printed Metrohm Information? The

answer is a clear «yes» (46 % of responses). Just under half of readers circulate Metrohm Information and a very large number archive it. All these factors certainly justify the admittedly high cost of a printed version. However, it must not be forgotten that 36 % want an elec-tronic version and 18 % both. PDF files (either sent by e-mail or for downloading) are more popular that an e-magazine. We editors see the two forms of publication coexisting and we are endeavoring to link them together in an ideal way – furthermore, we would like to make even better use of their respective strengths. Interaction and an exchange of opinions with our customers is the focus of attention at present and we will be taking steps to achieve this very shortly. Many predominantly positive comments and suggestions (including some concerning Metrohm in general) from our readers reinforce our plan.

Congratulations to the winnersAlongside the customer survey, we also ran a competition with

high-quality bags, a notebook and purses from the Swiss company Freitag as prizes. The lucky winners were chosen at random early in December: Matthias Leidig, David Swanson, Andreas Boehm, Beniken

Brahim, Doris Kellner, Susanne Grimm, Urs Waldburger, Fabiano Teixeira de Oliveria, Ping Ling, and Willi Feyrer. Congratu lations! Dr. Kai Viehweger and the editorial team of Metrohm Information are pleased that these people came from several different countries around the world: Brazil, Australia, Morocco, Malaysia, Austria, Germany, and Switzerland.

Where do we go from here?Our customer magazine and our style are liked very much by

the readers. This is a comfortable position to be in and requires no drastic measures. However, it does not mean that we can take things easy. In order to be able to meet your wishes and needs even more effectively, we will examine individual requests and then incorporate them in our production process. No doubt, we will develop our contact with you, our readers, even further. We are pleased that you are still reading our magazine and hope that, through it, we can give you some useful ideas and make your day-to-day work easier.

Dr. Benedikt GallikerEditor of Metrohm Information

One of the many comments from our readers:Most companies seem to be switching to a social networking approach and yet I work for a company that blocks sites such as Facebook, MySpace (although LinkedIn is fine), and video sites such as YouTube. At this stage, your information is quite accessible, well written, and easily understood. Congratulations, I associate your brand with excellent quality and functionality also when compared to competitors (e.g., Mettler, Dionex, etc.).

Radio IC for quality control in PET diagnostics

The PET Technological Institute ITP – cutting edge technology in Spain

The Madrid-based PET Technological Institute (Instituto Tecnológico PET, ITP) was created in 1994 in close cooperation with Madrid`s Complutense University. The cyclotron was installed in the same year and was the first in Spain. Since then, ITP has been the pioneer in the development of PET technology, both regarding production of radiopharmaceuticals and diagnostics. ITP is currently the only radiopharmaceutical laboratory in Spain which vertically inte grates production, marketing, and distribution of radiopharma-

ceuticals for human use and research. To meet the increasing radiotracer demand, a second laboratory with another cyclotron was inaugurated in June 2009. Since its foundation, the company has made about 25,000 PET studies and since the last quarter of 2009, ITP has brought five new radiotracers to the market.

The IC specialists of the Spanish Metrohm distributor Gomensoro have installed a custom-tailored, multichannel ion chromatography system that has taken over the quality control for three radiotracer production lines.

One of the two ITP cyclotrons for the production of PET radionuclides.

Customer application report

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Principles of positron emission tomography (PET)Radiopharmaceuticals are radioactive substances used in nuclear

medicine to diagnose, treat, or prevent disease. They contain a radioactive isotope, a so-called radionuclide, attached to a biologi-cally inert or active molecule.

Radionuclides are unstable isotopes that have an excess of either neutrons or protons and therefore radioactively decay, resulting in the emission of gamma rays or subatomic particles. In proton-rich nuclides, a proton (p+) changes to a neutron, whereby a positron (antiparticle of the electron or an electron with a positive charge, also called β+ particle) is emitted together with a neutrino (ν) according to

(p+) g (n) + (β+) + (ν)

While travelling in the surrounding media, the released positron loses its kinetic energy and then combines with an electron. The encounter annihilates both positron and electron and their masses are directly converted into energy. Two photons (gamma rays) each with an energy of 0.511 MeV are emitted in opposite directions (annihilation radiation).

me+ + m

e– g 2γ

Sophisticated scanners can detect such pairs of photons by means of coincidence detection. From the data collected, three-dimensional images of tissue structures are then calculated. The positron-emitting radionuclide is also called tracer. The most commonly used short-lived cyclotron-produced radionuclides in radiopharmacy are 11C, 13N, 15O, and 18F. The respective half-lives are 20.38, 9.96, 2.03, and 109.7 min.

RadiopharmaceuticalsTo administer the radionuclide to a living human or animal, it is

either incorporated in a biologically inert molecule (e.g., the blood flow tracers [15O]water or [15O]butanol or in a biologically active molecule that is absorbed by the organ of interest.

After the radiopharmaceutical is concentrated in the tissue of interest, the patient is placed in the PET scanner. By tracking the photons, computers with sophisticated software generate three-dimensional images of the source of the photons. This allows to study physiological, biochemical, and pharmacological functions at a molecular level. Illnesses like cancer, cardiovascular disease, and even neurological disorders can be detected long before symptoms appear.

Principle of positron emission tomography

Dr. Jesús Chesa-Jiménez, quality control department supervisor at ITP using Metrohm‘s ion chromatography system.


20

Production of PET radiopharmaceuticalsRadionuclides used in PET experiments such as 11C, 13N, 15O,

and 18F are artificially produced in a cyclotron, where a beam of ac-celerated charged particles irradiates a prepared target. Subsequently, the resulting radionuclides are isolated and synthetically incorporated into the radiotracer.

As the fluorine atom is similar in size to the hydrogen atom, it acts as a pseudohydrogen and is therefore ideally suited for replacing hydrogen atoms in organic molecules. The positron emitter 18F is thus one of the most important imaging radionuclides in diagnostic nuclear medicine. It is produced by proton bombardment of an 18O-enriched water target. In a 18O(p, n)18F reaction, highly accelerated protons (p) react with the 18O atomic nucleus to emit a neutron (n) and 18F, which immediately decays by positron emission with a half-life of 109.7 min. The product of the 18F decay is the stable isotope 18O. After isolation of 18F from the target water, the radionuclide is incorporated into the chemical compound required in a radiosynthe-sis. After isolation and purification, the obtained 18F radiotracer has to comply with a variety of quality control tests before administration to the patient.

[18F]Fluorodeoxyglucose[18F]Fluorodeoxyglucose, commonly abbreviated [18F]FDG, or

simply FDG, is a glucose analog in which the hydroxyl group at the 2‘ position of the glucose molecule is substituted by [18F]fluorine. It throws light on use and metabolism of glucose in heart, lungs, and brain. Additionally, it is used in oncology to determine abnormal glucose metabolism to characterize different tumor types. After administering [18F]FDG to the patient, it is incorporated into the cells by the same transport mechanism as the normal glucose, but unlike

this, it is not metabolized and thus remains in the cell allowing PET tomographic imaging. Not least due to its many diagnostic uses, the high number of existing labeling procedures and its advantageous half-life of approximately two hours, which allows the transport to sites that have no cyclotron, [18F]FDG is actually the most frequently used organic PET radiopharmaceutical.

[18F]FluorocholineIn cells, choline is used as a precursor for the biosynthesis of

phospholipids. As the latter are essential cell membrane compo-nents and because tumors reveal increased metabolism of cell membrane constituents and increased choline uptake, radiolabeled choline tracers are invaluable diagnostic tools for cancer detection. [18F]Fluorocholine is a recently developed PET radiotracer that allows to image choline metabolism in vivo. It is based on the tumor-detecting radiotracer [11C]choline. Driving force of the production of the 18F-labeled derivative was the substantially longer half-life, which allows the distribution of this tracer to PET institutions without on-site cyclotron.

Metrohm`s radio ion chromatographyCurrently, two different Metrohm ion chromatography systems

have been installed in the quality control labs of ITP in Madrid. The first one is a customized ion chromatography system that was installed at the beginning of 2010. It was designed for the quality control of the radionuclide [18F]fluoride and the two radiotracers [18F]FDG and [18F]fluorocholine synthesized from this precursor. Besides the accuracy and reproducibility of the analytical results, high throughput is a must. One and the same multichannel radio IC takes over the quality control of three production lines. The analytical unit provides the following benefits:

(a) Conductivity and (b) radioactivity chromatogram of cyclotron-produced [18F]fluoride. In the subsequent radiosynthesis (nucleophilic fluorination), trace (i.e., very low) quantities of [18F]fluoride ions are used to form carbon-fluorine bonds. The IC software converts the radiation units, counts per second (cps), to mV. Chromatographic conditions are shown in the table.


Chromatographic conditions for the quality control of [18F]fluoride, [18F]FDG, and [18F]fluorocholine.

[18F]fluoride [18F]FDG [18F]fluorocholine

Column Metrohm A Supp 5 - 150/4.0 Metrosep Carb 1 - 150/4.0 Metrosep C 4 - 150/4.0

Column temperature 45 °C 25 °C 40 °C

Sample volume 10 μL 10 μL 10 μL

Eluent 3.2 mmol/L sodium carbonate1.0 mmol/L sodium hydrogen

carbonate

0.1 mol/L sodium hydroxide 1.7 mmol/L nitric acid0.7 mmol/L dipicolinic acid

Flow rate 0.7 mL/min 1.0 mL/min 1.5 mL/min

Detection Conductivity detection after

chemical suppressionPulsed amperometric detection Conductivity detection

Analysis time 8 min 18 min 14 min

21


Flexibility of the systemThe ion chromatography system installed at ITP combines three

quality control systems for PET pharmaceuticals in one. From the very same injection system, the flow can be automatically directed to the three channels. By selecting between an array of different columns, mobile phases, and detectors, [18F]fluoride, [18F]FDG, and [18F]fluoro-choline can be separately determined. All aspects of system operation and data acquisition are controlled by MagIC Net™ software.

Safety The automated sample injection with Metrohm`s Dosino techno-

logy allows the aspiration of very low sample volumes with accuracy and precision. By using the MagIC Net™ software, liquid handling as well as dosing and rinsing tasks are completely automated without any carryover. The modular design of the Metrohm IC supports the installation of the required lead shielding and thus guarantees user safety. The injection valve is placed inside a 5 cm thick tailor-made lead housing, while radiation from the radiotracers in the separation columns is attenuated to a safe level by a suffi ciently thick lead shielding. Additionally, a lead sample holder avoids user exposure to gamma radiation.

Comprehensive quality control made easyRadiopharmaceuticals have unique characteristics and require

special tests (described in numerous pharmacopoeias) before the radiotracer can be administered to the patient. The quality control includes testing the chemical and radiochemical purity of the radio-tracer. The radiochemical purity of a radiotracer – the ratio of the radionuclide in bound form (e.g., [18F]FDG) to the radionuclide in unbound form (e.g., [18F]fluoride) – guarantees the image quality of the PET scan and protects the patient from unnecessary radiation.

In the first place, the concentration of the cyclotron-produced radionuclide, which is used as a precursor in the subsequent radio-synthesis, has to be determined.

Subsequently, the appropriate chemical purity – as for any other pharmaceutical preparation – and the concentration of the synthesized radiopharmaceutical, which mostly is in the nanomolar range, has to be determined. In doing so, also excessive precursors and radiolabeling-derived impurities have to be quantified. The chromatogram shows the peaks of the glucose precursor, the carrier-free [18F]FDG, and the chlorodeoxyglucose impurity. The analysis is completed in less than 10 minutes.

Chemical structures of two PET radiopharmaceuticals. (a) In [18F]FDG, the hydroxyl group at the 2‘ position of normal glucose is substituted by 18F. (b) In [18F]fluorocholine, a [18F]fluoroalkyl group is attached to the nitrogen atom of N,N-dimethylaminoethanol (DMAE).

OH

HOO

HOF18

OH

N+

F18OH

Br–

(a) (b)OH

HOO

HOF18

OH

N+

F18OH

Br–

(a) (b)

(a) Conductivity and (b) radioactivity chromatogram of cyclotron-produced [18F]fluoride. In the subsequent radiosynthesis (nucleophilic fluorination), trace (i.e., very low) quantities of [18F]fluoride ions are used to form carbon-fluorine bonds. The IC software converts the radiation units, counts per second (cps), to mV. Chromatographic conditions are shown in the table.


(a) (b)

22

Chromatograms for the radiopharmaceutical [18F]FDG. (a) IC-PAD chromatogram with the glucose precursor, the carrier-free [18F]FDG, and the impurity chlorodeoxyglucose. (b) Radioactivity chromatogram of the [18F]FDG. The IC software converts the radiation units, counts per second (cps), to mV. Chromatographic conditions are shown in the table.

Chromatograms for the radiopharmaceutical [18F]fluorocholine. (a) Conductivity and (b) radioactivity chromatogram of the [18F]fluorocholine reaction mixture. [18F]Fluorocholine is synthesized by 18F-fluoroalkylation of N,N-dimethylaminoethanol (DMAE) using gaseous 18F-fluorobromomethane. This labeling reaction results in high levels of residual DMAE. Other potential byproducts such as bromocholine (not detected here) can additionally be determined. The IC software converts the radiation units, counts per second (cps), to mV. Chromatographic conditions are shown in the table.

The chromatogram of the reaction mixture of the [18F]fluo-rocholine synthesis shows, besides nanomole quantities of the [18F]fluorocholine radiotracer, considerable amounts of the reactant N,N-dimethylaminoethanol and trace levels of calcium impurities.


Analysis timeAs most positron-emitting radiopharmaceuticals are characte-

rized by short half-lives, there is a constant drive to reduce the time spent on quality control. Fast and precise analyses are guaranteed by optimally harmonized and computer-controlled determination and rinsing sequences for detector pathways and the sample injection circuit.

23


The IC specialists of Gomensoro adapted the Metrohm IC system to the needs of ITP (left to right): Javier Espuelas (Applications Laboratory Manager), Cristobal Hidalgo (Calibration Manager), Vicente Ubeda (Sales Manager), Juan Lopez (Metrohm Sales Manager), Miguel Espinosa (Ion Chromatography Product Manager), Andoni Epalza (IC Application Specialist), and Tomas Sanz (IC Application Specialist).


ConclusionMetrohm`s highly customizable chromatography system copes

with the tough requirements of the radiopharmaceutical industry and pharmacopoeial regulations. One single multichannel radio IC meets the quality control requirements of various production lines. Besides the high quality, the Metrohm IC presented ensures user safety, low maintenance costs, and outstanding ruggedness.

AcknowledgementsThe authors thank Dr. Jesús Chesa-Jiménez from ITP for his

support and fruitful discussions during this project.

Further reading(1) D. Slaets, S. De Bruyne, C. Dumolyn, L. Moerman, K. Mertens,

and F. De Vos, Reduced dimethylaminoethanol in [18F]fluoro-methylcholine: an important step towards enhanced tumour visualization, Europ J Nucl Med Mol Imaging 37(11), 2136–2145 (2010).

(2) Cyclotron-produced radionuclides: physical characteristics and production methods, Technical Report Series No. 468, International Atomic Energy Agency, Vienna, 266 p. (2009).

(3) D. Kryza, V. Tadino, M. Azuzurra Filannino, G. Villeret, and L. Lemoucheux, Fully automated [18F]fluorocholine synthesis in the TracerLab MXFDG Coincidence synthesizer, Nucl Med Biol 35, 255–260 (2008).

(4) J. Passchier, Fast high-performance liquid chromatography in PET quality control and metabolite analysis, Q J Nucl Med Mol Imaging 53, 411–416 (2009).

24 Determine hexavalent chromium according to EPA Method 218.7

Hexavalent chromium released into nature ends up in drinking water, causing significant contamination: even minute doses are harmful to the environment and to health. This article reveals how hexavalent chromium can enter the environment and how it can be analyzed.

Metrohm USA, working closely with the U.S. Environmental Protection Agency (EPA), has developed a highly sensitive ion chro-matographic method for determining hexavalent chromium that is now part of the latest EPA Method 218.7. The analysis is explained in detail on the web page info.metrohmusa.com/hexachrome/latest-news.html, where you can also download the latest EPA Method 218.7 free of charge.

Uses and properties of chromium and its saltsIn the environment, chromium is encountered primarily in the

two forms Cr(III) and Cr(VI). Whereas Cr(III) compounds pose no major risk (and are essential for humans), hexavalent chromium (also called hexachrome, chrome-6, and Cr(VI)) is harmful. The strong oxidizing agent Cr(VI) is classified as carcinogenic, mutagenic, and damaging to the DNA. Acute chromium(VI) poisoning leads to renal damage. Chronic Cr(VI) exposure can lead to changes in the gastrointestinal tract. If inhaled, it can cause lung cancer. Because hexavalent chromium dissolves very readily in water, the result is high bioavailability and mobility.

Chromium is used in the production of steel (added to give greater hardness and resistance to corrosion), in the electroplating industry (surface treatment by means of chromium plating; passive films by means of chromatization), in leather production (chrome tanning), and as a pigment in dyes and coatings. Chromium was also used as an impregnating agent for wood. Limestone and clay, the starting materials for cement, also contain chromium in the form of Cr(III), some of which oxidizes to Cr(VI) during the production of cement.

Examples of the release of hexavalent chromium into the environment

A study by the «Environmental Working Group» (EWG), an American environmental organization, in 2010 revealed that more than 74 million Americans in 42 U.S. states consume drinking water that is contaminated with hexavalent chromium. Cr(VI) was detected in 31 of 35 drinking water samples from throughout America; 25 samples even contained a worryingly high dose. In the mid-1990s there was a hexachrome scandal, when legal assistant Erin Brockovich discovered that the company «Pacific Gas and Electric» in Hinkley, California, had discharged hexavalent chromium into the ground-water over a period of several years. Numerous people became ill at that time and some even died.

In China, too, there are problems with hexavalent chromium in drinking water. A chemical plant in Qujing, a city in Yunnan province, had to be shut down by the authorities in 2011 after it was revealed that it had dumped more than 5,000 metric tons of toxic chromium waste into a nearby river and the surrounding area and deposited 140,000 metric tons of chromium waste in its own dump close to the river.

Worldwide, the leather industry uses chrome tanning with Cr(III) salts (e.g., chromium sulfate) as the most common tanning process. Cr(VI) can result from improper tanning conditions, or even be contained already as an impurity in the tanning chemicals. Even the smallest quantities of Cr(VI) in the leather trigger inflammatory skin reactions when they come into contact with the skin (contact allergen). This chromate allergy (“bricklayer’s itch”) can, inciden-tally, also be brought on by cement-containing building materials. Conventional leather tanning requires a very large quantity of water; the wastewater contains readily water-soluble hexavalent chromium. Inadequate wastewater purification and illegal dumping (e.g., of leather waste) lead to pollution of the groundwater. This can be seen, for example, in the Indian city of Kanpur on the Ganges. In 2006, the «Blacksmith Institute», an environmental organization, included Kanpur among the ten most polluted places on earth.

Hexavalent chromium is also an issue in Europe. In Switzerland, it is estimated that up to ten metric tons of chromium(VI) pigments were used for decades after 1970 in the form of coatings with a heavy-metal content to protect bridges, vertical tanks, pressurized pipelines etc. As a result of (improper) remediation work, it is reckoned that up to 300 kilograms of Cr(VI) enters the environment annually across Switzerland. This is evident from a report of Empa, the Swiss Federal Laboratories for Materials Science and Technology.

Practical tips

25Determine hexavalent chromium according to EPA Method 218.7

The purpose of this article is not to point the finger at individual countries. Hexavalent chromium and its release into the environment is a global problem that affects millions of people, especially through the consumption of drinking water. Access to clean drinking water has been a human right since 2010 according to a UN declaration!

Regulations on the use of hexavalent chromium in the EUThe RoHS Directive severely restricts the use of Cr(VI) compounds

in Europe: from 1 July 2006, new electrical and electronic equipment that is put on the market is no longer allowed to contain any Cr(VI), mercury, cadmium, lead, or brominated flame retardants. The EU End-of-Life Vehicles Directive prohibits (with a few exceptions) the use of lead, Cr(VI), cadmium, and mercury in the automotive sector.

Limits for hexavalent chromiumThe drinking water standard of the U.S. EPA provides for a

maximum concentration of total chromium in drinking water (inclu-ding Cr(III), Cr(VI), and other forms) of 100 μg/L or 100 ppb. The state of California applies stricter limits: since 31 December 2010, the public health goal for hexavalent chromium has been 0.02 μg/L. The EU limit for total chromium, which is the same as that of the World Health Organization (WHO) and the German Drinking Water Ordinance (Trinkwasserverordnung), is 50 μg/L. The Swiss limit for hexavalent chromium is 20 μg/L.

Metrohm method is used by EPA to monitor limitsExtremely sensitive measuring methods are required to moni-

tor compliance with the limits. Working closely with the U.S. EPA, Metrohm developed an extremely sensitive ion chromatographic method for detecting Cr(VI) that is now part of the most recent EPA Method 218.7. The achievable detection limit with this method is lower than the very strict Californian limit of 0.02 μg/L for hexavalent chromium.

Here you can find out all you need to know about Cr(VI) determination according to EPA 218.7: info.metrohmusa.com/hexachrome/latestnews.html

Are you interested in other Metrohm applications? On the web page www.metrohm.info you will find information on further applications for downloading.

Valuable tips on how hexavalent chromium can be determined using ion chromatography are revealed by Metrohm USA on the web page info.metrohmusa.com/hexachrome/latestnews.html. There you can download the Application Work AW IC US6-0152-012011 «Determination of Hexavalent Chromium in drinking water, ground water and surface water by Ion Chromatography followed by Post Column Reaction (PCR) and UV/Vis detection (conforming to USEPA method 218.7)» and the EPA Method 218.7 that is based on it. In addition to further background information, the web page also shows you how you can determine Cr(VI) voltammetrically. It’s worth a look!

26

For our customers and all other interested parties there are more than 1500 applications, covering a wide variety of application fields and analytical methods, available free of charge in the Metrohm application databasehttp://www.metrohm.com/com/Applications.

The following new Application Bulletins and Application Notes have been published recently:

Application Bulletins• AB-344 Automated analysis of etch acid mixtures using the

859 Titrotherm and the 814 USB Sample Processor• AB-345 Installation instruction for «ProfIC 6 – Anion»• AB-346 Installation instruction for «ProfIC 6 – Cation»• AB-347 Installation instruction for «ProfIC 12 – Anion»• AB-348 Installation Instruction for an Anion Low Pressure

Gradient• AB-349 Installation instruction for an Anion Dosino Gradient• AB-350 Installation instruction for «ProfIC 8 – Anion»• AB-351 Installation instruction for «ProfIC 8 – Cation»• AB-352 Installation instruction for «ProfIC 10 – Anion»

Application NotesThermometric titration• AN-H-102 Determination of hypochlorite by titration with

ammonium ion• AN-H-103 Determination of calcium and magnesium in milk• AN-H-104 Determination of free acid content of

hydrometallurgical leach liquors• AN-H-105 Determination of nickel in hydrometallurgical leach

liquors

• AN-H-106 Determination of magnesium content in hydrometallurgical leach liquors

• AN-H-107 Determination of ferrous ion content in hydrometallurgical leach liquors

• AN-H-108 Determination of ferric ion in hydrometallurgical leach liquors

• AN-H-109 Determination of sulfuric acid, hydrofluoric acid, and ammonium bifluoride in acid mixtures

• AN-H-110 Determination of sulfate in drinking water by barium chromate displacement

• AN-H-111 Determination of sulfate in harvested salt• AN-H-112 Determination of total sodium in commercial

cheeses by thermometric titration• AN-H-113 Determination of nitric acid, hydrofluoric acid, and

iron in acid etching baths• AN-H-114 Determination of sulfuric acid, nitric acid, and

hydrofluoric acid in etch solutions• AN-H-115 Determination of hydrofluoric acid, ammonium

fluoride, and maleic acid in acid cleaning solutions• AN-H-116 Determination of rhodium and ruthenium as

well as the acid content of plating solutions by thermometric titration

Potentiometric titration• AN-T-073 Fully automated determination of conductivity, pH

value, and alkalinity in tap water including sample preparation

• AN-T-074 Fully automated determination of conductivity, pH value, alkalinity, and hardness in tap water including sample preparation

New Metrohm application literature

Application literature

27


New Metrohm application literature

• AN-T-075 Fully automated determination of conductivity, pH value, alkalinity, and chloride in tap water including sample preparation

• AN-T-076 Fully automated determination of conductivity, pH, alkalinity, hardness, and chloride in tap water with sample preparation

Ion chromatography• AN-C-133 Tap water analysis for anions and cations using

Metrohm intelligent Partial Loop Technique (MiPT)• AN-P-044 Glucose, fructose, and sucrose in banana applying

pulsed amperometric detection• AN-S-286 Sulfate and sulfamate analysis in Topiramate as per

USP 33 - NF 28 Suppl. 1• AN-S-287 Tap water analysis for anions and cations using

Metrohm intelligent Partial Loop Technique (MiPT)• AN-S-288 Determination of anions in tap water within five

minutes on Metrosep A Supp 16 - 100/2.0 column• AN-S-289 Determination of eight organic acids besides the

standard anions on the Metrosep A Supp 16 - 250/2.0 column

• AN-S-290 Chlorine, bromine, and sulfur in low density polyethylene (ERM®- EC680k) applying Combustion Ion Chromatography (CIC)

• AN-S-291 Reproducibility of the Metrohm Suppressor Module (MSM)

• AN-U-051 Bromate with 887 Professional UV/VIS Detector and 886 Professional Thermostat / Reactor according to draft ISO/DIS 11206

• AN-U-052 Transition metal cations applying UV/VIS detection after post-column reaction with PAR (4-(2-pyridylazo)resorcinol)

• AN-U-053 Chromate with 887 Professional UV/VIS Detector and 886 Professional Thermostat / Reactor

• AN-U-054 Amino acids applying UV/VIS detection after post-column reaction with ninhydrin at 120 °C

• AN-U-055 Amino acids in cell culture growth medium applying UV/VIS detection after post-column reaction with ninhydrin at 120 °C

• AN-U-056 Nitrite, bromide, and nitrate in artificial sea water applying direct UV/VIS detection

Voltammetry/amperometry• AN-V-194 Copper in ethanol and fuel ethanol (E85) for car

engines• AN-V-195 Iodate in electroless nickel baths• AN-V-196 Antimony and bismuth in electroless nickel baths• AN-V-197 Iodide in NaCl brine electrolytes of chlor-alkali

electrolysis plants• AN-V-198 Aluminum in drinking water by adsorptive stripping

voltammetry using alizarin red S (DASA) as complexing agent

• AN-V-199 Determination of gold(I) in gold plating baths• AN-V-200 Thiourea in copper electrolytes in copper

electrorefining plants

Stability measurements• AN-R-011 Oxidative stability of instant noodles• AN-R-012 Oxidative stability of different solid foodstuffs

Imprint

Volume 41, Issue 1ISSN 1424-0904

Metrohm Information is the customer magazine of Metrohm International Headquarters and is published twice a year in English and German.Please contact us if you wish to receive your own copy regularly.

Published by:Metrohm International HeadquartersMetrohm InformationCH-9101 Herisau/Switzerland

Chief editor:Dr. Kai H. [email protected] Editors:Dr. Benedikt [email protected] [email protected] Layout:Ecknauer + Schoch, Werbeagentur ASW Printed by:Metrohm International Headquarters

New: further applications & electronic editionThe electronic edition of our customer magazine Metrohm Information and the archive with all editions from 2005 to 2012 is available on www.metrohm.info. There you will also find our newest literature references as well as further information on applications for downloading.

CH-9101 Herisau/[email protected] www.metrohm.com

CH-9101 Herisau/[email protected] www.metrohm.com