pH and ICP TechniquespH and ICP TechniquesClemson

pH quality control checkspH quality control checks

Scoop 2 checksOne blankDouble scoop 6 samplesTag set with lab

number, check, and blank positions

Quality control rowQuality control row

Two QC check samples Two samples at beginning, middle,

and end of set Cross Check electrodes #1 and #2

2 31

End of run verificationEnd of run verification

Check both QC check values at beginning and within set Check all double scooped samples at beginning, middle,

and end of set Buffer run - checks Buffer run - blank (1:1, water:buffer)

ck

MaintenanceMaintenance

Friday◦ clean out electrode filling solution ◦ fill with water

Ultrasonic cleaner Store in buffer pH 7 for the

weekend

Maintenance – cont.Maintenance – cont.

Monday◦ Take water out of electrode◦ Refill with KCl filling solution

Verify flow of KCl through filter Refresh buffer solutions Electrode (from Fisher)

◦ Accumet rugged bulb pH combination electrode

◦ 13-620-183A

pH Check valuespH Check values

Check B data since April 1, 2010 115 continuous reads over a 2.5 month period Rinse pH < 4.5 and > 7.0 NAPT value 5.15 Lab average 5.15 stdev 0.036

ICP quality control checksICP quality control checks

Two checks within the setOne blank

Sample entrySample entry

Probe – Leeman Labs◦ Phone: 603-886-8400◦ Part number 902-00017

Check all tubing for cleanliness and kinks Change pump winding tube when needed Adjust pump winding clamp - look for smooth

flow as sample travels though tube

Nebulizer gas flowNebulizer gas flow

Aspirate yttrium stock solution Look for the tip of the red bullet Adjust nebulizer gas flow rate

TJAARCOS

Nebulizer and spray chamberNebulizer and spray chamber

Keep clean◦ Take apart to rinse out nebulizer

and spray chamber parts TJA – use cleaning wire ARCOS

◦ SeaSpray Nebulizer◦ Twister Spray Chamber◦ Cross Flow

TJA

ARCOS

ARCOS

TorchTorch

ARCOS – clean as needed – salt buildup TJA – clean ~once a year

TJAARCOS

Setting the flush timeSetting the flush timeARCOS - CrossflowARCOS - Crossflow

Transient scan – run standard Check to see when the peak intensities stabilize Clemson – 35 second total flush

◦ 25 seconds at 60 rpm◦ 10 seconds at 30 rpm

25 seconds

Time (seconds) using pump speed of 60 rpm

P

K

Transient scan on ARCOSTransient scan on ARCOS

18 seconds

25 seconds

Crossflow spray chamber Twister spray chamber

Transient scan going to Transient scan going to rinserinseARCOS - CrossflowARCOS - Crossflow

Options for changing flush time◦ Spray chamber◦ Tubing length◦ Pump speed◦ Sample loop

Ca – 100 ppm

Na – 50 ppm

P – 100 ppm

K – 100 ppm45 seconds

Time in seconds using pump speed of 60 rpm

25 seconds

Setting the flush time - TJASetting the flush time - TJA

Run time scan Check time for stability Clemson soil method

◦ pump speed 200 rpm◦ flush time 30 seconds

Ca - 40 seconds

Pump speed 175 rpm

Line selection – ARCOSLine selection – ARCOS

Look at several recommended lines Clemson - Ca line – 317.933 for soil

Ca – 396.847Saturated signal

Ca – 315.887

Method development - ARCOSMethod development - ARCOS

Set peak position Select clean area

for background subtraction

Look for uncontaminated blank

Cu – 324.754

blank

Peak position

Blank correction

Instrument profile and data Instrument profile and data verificationverification

Run profile when needed On the AROCS - check intensity of

P158.599 line If significant UV intensity drop – clean

window and/or lens to optics

Check new standard against old Read reference sample at start, mid

point, and end of run Verify 2 check samples and blank

within set