pH and ICP Techniques Clemson

pH quality control checks Scoop 2 checks One blank Double scoop 6 samples Tag set with lab number, check, and blank positions

Quality control row Two QC check samples Two samples at beginning, middle, and end of set Cross Check electrodes #1 and #2 231

End 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

Maintenance Friday ◦clean out electrode filling solution ◦fill with water Ultrasonic cleaner Store in buffer pH 7 for the weekend

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 ◦ A

pH Check values Check B data since April 1, continuous reads over a 2.5 month period Rinse pH 7.0 NAPT value 5.15 Lab average 5.15 stdev 0.036

ICP quality control checks Two checks within the set One blank

Sample entry Probe – Leeman Labs ◦Phone: ◦Part number 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 flow Aspirate yttrium stock solution Look for the tip of the red bullet Adjust nebulizer gas flow rate TJA ARCOS

Nebulizer 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

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

Setting the flush time ARCOS - 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 ARCOS 18 seconds 25 seconds Crossflow spray chamber Twister spray chamber

Transient scan going to rinse ARCOS - 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 ppm 45 seconds Time in seconds using pump speed of 60 rpm 25 seconds

Setting 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 – ARCOS Look at several recommended lines Clemson - Ca line – for soil Ca – Saturated signal Ca –

Method development - ARCOS Set peak position Select clean area for background subtraction Look for uncontaminated blank Cu – blank Peak position Blank correction

Instrument profile and data verification Run profile when needed On the AROCS - check intensity of P 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