We’ve all seen it. On TV a problem is solved in less than 60 minutes, with time to spare for commercials. This is rarely the case in the real world. When it comes to laboratory analysis, there is typically more going on behind the scenes than one may be led to believe. For instance, in the case of analyzing a soil sample for polycyclic aromatic hydrocarbons (PAHs) by the Environmental Protection Agency Method 8270D, “Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS),” there are five major steps from collection of the sample to the delivery of results to your inbox.

Sample receipt and log inUpon arrival, the 4 ounce jar containing the sample is received and the temperature blank from the cooler is measured and recorded. The chain of custody (COC) is referenced for all of the client, site, and project information, including the analyses requested and sampling date and time. This data is entered into the Laboratory Information Management System (LIMS) software that tracks everything about this sample throughout the process, including generation of the final report and invoice. An accurate COC is critical for accuracy and efficiency of the process. All sample bottles are labeled with a unique number and letter and then put in the walk-in cooler for storage.

Sample extractionTo start off, the PAH compounds must be separated from the soil by a process called extraction. This is similar to making a cup of tea. The tea bag is submerged in boiling water to extract the flavor compounds into the water and away from the tea leaves. In the case of our soil sample, it is weighed accurately and a solution containing surrogate compounds is added. These compounds have properties similar to the compounds of interest, but are not naturally found. By adding a known amount of surrogate compounds, the recovery after analysis is used to assess how well the extraction process worked. The soil sample is transferred to a vessel, and a solution of acetone and methylene chloride is added. The compounds of interest are soluble in these solvents. To make the extraction effective, elevated temperature and pressure are applied using a microwave. The soil is filtered away from the extract and excess solvent is evaporated, leaving 1 milliliter, or about 1/4 teaspoon, for analysis. Samples are prepared for analysis in batches of no more than 20 samples.

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Reality Check The Truth About How a Soil Sample is Analyzed

continued on page 3 …

By Rebecca Hofstad, Ph.D.,Analytical Laboratory Technical Director rhofstad@braunintertec.com

A microwave instrument is used to extract compounds under conditions of elevated temperature and pressure.

A B R A U N I N T E R T E C P U B L I C A T I O N

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Formulating Change Part II

In my last column, I discussed the change and progression of our analytical laboratory, and now I want to tell you the benefits these changes have had on the way we deliver our

services. Looking back at our corporate office move in 2002, we designed and built our laboratory facility to provide a true “business separation” from the rest of the organization. This was necessary to better serve both external and internal clients by protecting the confidential relationships with each individual account and client, eliminating potential conflicts of interest and meeting the various laboratory certification requirements. By design, the laboratory specifically has its own separate security, invoicing, data collection and reporting systems.

In a number of situations, the laboratory has bid on the same project as a partner with both external and internal clients. Because relationships with both parties are equally important to us in the laboratory, it has always been and remains our strategy to provide the same pricing structure to both groups. Beginning about ten years ago, the majority of the laboratory revenue comes from clients outside of Braun Intertec – this remains true today.

As reporting technology has changed drastically over the last decade, our electronic data deliverable options have changed greatly as well, including customized spreadsheets, client data portals, various types of database formats, and third-party invoicing. Fully utilizing technology helps to speed up data delivery, provide more report customization and of course, reduce paper consumption. Currently, our laboratory only sends out a few hardcopy reports through snail mail, and seemingly, the fax has gone the way of the dinosaur.

Going forward there will be many more advancements in data collection, instrumental technology, electronic deliverables, overall information, and methods. But the one thing that will remain constant is data quality. Data quality trumps everything else. ■

Tom Wagner, Analytical Laboratory Manager twagner@braunintertec.com

Braun Intertec Analyst Profile: Cindy Schultz, Lab Analyst III

Meet Cindy Schultz. Cindy supervises the Braun Intertec inorganic group and is the primary analyst for inductively coupled plasma mass spectrometry (ICP-MS) and mercury analyses. The ICP-MS is an instrument that measures the low level metals in water like lead, arsenic, copper and up to 26 elements in total. Specifically, it looks for whether the metal levels are safe for drinking water or the environment. As you may know, mercury isn’t so great for human consumption either, so Cindy tests soil, air, and mostly water for the pesky element. Basically, she gets to play with all the fun stuff.

She also enjoys running the equipment and troubleshooting technical difficulties. “I want to know why it works, how it works, and what the issue is,” Cindy says. “I like getting in there and figuring it out,” she adds. As an analytical junky by nature, Cindy recently had the opportunity to work on and refine a fusion digestion process on concrete samples to break the oxides for the analysis of the mineral and metal content. This was a “fun” project.

With a Bachelors of Science in Fisheries and Wildlife Management from the University of Minnesota, she planned to consult on natural resources and the environment. But after working in a laboratory, Cindy enjoyed it so much she decided to stay. Fourteen years later, she’s still very happy in the lab, helping give people the highest-quality data she can to help her clients make better informed decisions.

When Cindy isn’t tinkering with equipment or solving environmental dilemmas, she spends time with her family and friends, reads novels, and rollerblades. ■

Cindy is busy opening microwave digest vessels as part of the ICP preparation method.

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Each batch, no matter how large or small, must also have a set of five quality control samples prepared with it. These include a method blank and two control samples using clean sand, and a pair of matrix spikes using an actual sample. From start to finish, the extraction of a batch of samples for this analysis takes 3 to 4 hours.

Instrumental analysisFor the analysis of PAHs a GC/MS is used. While the extraction is the most important step in getting things off on the right foot, this step is where the technological magic happens. In summary, one percent of the 1 milliliter extract is rapidly vaporized and introduced into a specially-coated, small diameter piece of tubing known as a column. As the vapor travels through the column, each compound interacts with the column coating to a different extent. These interactions separate the compounds from each other. The key is that each specific compound arrives at the end of the column at a different time. As a compound leaves the column, the molecules enter the mass spectrometer (MS) detector and are blasted with a specific amount of energy and broken into smaller pieces. This happens in a reproducible and characteristic way for each compound resulting in a mass spectrum, or a signature that identifies the compound. Prior to analyzing the samples, the instrument was calibrated with several solutions of known concentration that contain the analytes of interest. In addition, several checks of the instrument had to be performed to demonstrate that it was operating properly and accurately. This step of the journey for a batch of 20 samples takes about 12 hours and is generally started during the work day and left to run unattended overnight.

Data analysisData analysis is where the expertise of the analyst is critical to producing high-quality data. Sophisticated computer software converts all of the signals from the MS into information that is interpreted by the analyst. The known mass spectra of the

compounds of interest are compared to the unknown samples to identify and calculate a concentration for the compounds that are present. This is done one by one for each compound of interest in each sample. The software, in general, does a good job of selecting the information that is likely of interest, but it is the analyst who determines what information truly confirms the presence, identity, and concentration of compounds in the sample. This is no easy task as environmental samples typically contain compounds that interfere with the compounds of interest. The sample data may indicate a need for the sample to be re-analyzed to obtain more information, such as a dilution to eliminate some of the interferences. The data quality is also evaluated with respect to the recoveries of quality control samples and other requirements of the method. This step is more quickly accomplished when samples do not contain any compounds of interest or interferences. Since this is seldom the case, the time necessary varies based on the complexity of the samples.

Data review and reportingThe data reviewer is an expert in the method, but never the same person as the analyst. The reviewer examines all of the data, compares the results to the method requirements for all of the quality control parameters, and evaluates the information for each compound of interest in the samples. Similar to the data analysis step, the length of time for this process varies with the complexity of the samples. All along the way, data for each step has been added to the LIMS system. In the final step, it’s all pulled together by the project manager to generate a final report.

While the complexity and length of time varies quite a bit for the range of analyses conducted by the laboratory, the process always involves several staff members making every analysis a team effort. This process does not make for good TV, but does make certain that high-quality data is generated by a methodical, thorough process. ■

Soil samples are filtered to separate the soil from the extraction solvent.

The GC/MS software and an analyst with the right experience team up to analyze the data.

… Reality Check continued from page 1

©2013 Braun Intertec Corporation

Q&A: Cooler SamplingQ: What is the best method for cooling samples?A: Packing samples on regular ice is the best method to cool samples, and it cools best when packed freely and not in bags. Dry Ice can be a hazard to handle, is not allowed on airplanes and can potentially freeze the samples. Blue Ice packs are not recognized by regulatory agencies as a proper preservation and cooling technique.

Q: What is the best way to pack a cooler?A: There should be a layer of bubble wrap on the bottom of the cooler and all glass containers should be bubble bagged and packed standing upright. Pack the cooler loosely and fill all voids with ice to provide support. The more ice the better!

Q: What is a temperature blank for and what temperature should the samples be for analyses?A: The temperature blank is used to measure the temperature of each cooler when it’s received in the lab to determine if the samples were provided under proper testing conditions. Samples should be cooled to 6˚C (42˚F) or less but not frozen.

Q: What are custody seals?A: Custody seals are used to verify that the cooler has not been tampered with, compromising the integrity of your data. They are usually used when sending samples through a courier or other delivery service. The custody seal needs to be signed and dated then placed across the cooler lid opening.

Q: How should bottle labels be filled out?A: At a minimum, fill out bottle labels with a permanent marker and differentiate your samples by a unique name, date, and time sampled.

Analytical Laboratory Summer Hours

Open Saturdays from 8 a.m. until noon, extending until Oct. 26, with the exception of Memorial Day, Independence Day and Labor Day weekends. Our normal receiving hours are Monday through Friday, from 8 a.m. until 5 p.m.

This newsletter contains only general information. For specific applications, please consult your engineering or environmental consultants and legal counsel.

Questions, requests and comments

Thomas Wagner 952.995.2650twagner@braunintertec.com

Steven Albrecht 952.995.2622salbrecht@braunintertec.com

Braun Intertec Corporation11001 Hampshire Avenue SMinneapolis, MN 55438