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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