pH and ICP Techniques
Clemson
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Scoop 2 checks
One blank
Double scoop 6 samples
Tag set with lab
number, check, and
blank positions
pH quality control checks
1
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2
3
Two QC check samples
Two samples at beginning, middle,
and end of set
Cross Check electrodes #1 and #2
Quality control row
ck
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)
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End of run verification
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Friday
◦ clean out electrode filling solution
◦ fill with water
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Ultrasonic cleaner
Store in buffer pH 7 for the
weekend
Maintenance
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
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Maintenance – cont.
5.3
5.25
5.2
5.15
5.1
5.05
5
0
20
40
60
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pH Check values
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80
100
120
140
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
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Two checks within the set
One blank
ICP quality control checks
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Sample 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
Aspirate yttrium stock solution
 Look for the tip of the red bullet
 Adjust nebulizer gas flow rate
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TJA
Nebulizer gas flow
ARCOS
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ARCOS
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Keep clean
◦ Take apart to rinse out nebulizer
and spray chamber parts
TJA – use cleaning wire
ARCOS
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SeaSpray Nebulizer
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Twister Spray Chamber
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Cross Flow
ARCOS
TJA
Nebulizer and spray chamber
ARCOS
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ARCOS – clean as needed – salt buildup
TJA – clean ~once a year
Torch
TJA
25 seconds
P
K
Time (seconds) using pump speed of 60 rpm
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Setting the flush time
ARCOS - Crossflow
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Transient scan – run standard
Check to see when the peak intensities stabilize
Clemson – 35 second total flush
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25 seconds at 60 rpm
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10 seconds at 30 rpm
18 seconds
25 seconds
Crossflow spray chamber
Twister spray chamber
Transient scan on ARCOS
P – 100 ppm
Ca – 100 ppm
K – 100 ppm
Na – 50 ppm
25 seconds
45 seconds
Time in seconds using pump speed of 60 rpm
Transient scan going to rinse
ARCOS - Crossflow
Options for changing flush time
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Spray chamber
Tubing length
Pump speed
Sample loop
Ca - 40 seconds
Pump speed 175 rpm
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Run time scan
Check time for stability
Clemson soil method
◦ pump speed 200 rpm
◦ flush time 30 seconds
Setting the flush time - TJA
Ca – 396.847
Ca – 315.887
Saturated signal
Look at several recommended lines
 Clemson - Ca line – 317.933 for soil
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Line selection – ARCOS
Peak position
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Set peak position
Select clean area
for background
subtraction
Look for
uncontaminated
blank
Cu – 324.754
Blank correction
blank
Method development - ARCOS
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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
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Check new standard against old
Read reference sample at start, mid
point, and end of run
Verify 2 check samples and blank
within set
Instrument profile and data
verification