US Long-Term Ecological Research Network

This instrument analyzes water samples for inorganic and organic carbon. The total analysis time is 8 minutes per sample. The instrument displays the inorganic carbon result at 3 minutes and the organic carbon result 5 minutes later. Results are fed to a printer and displayed as ppm carbon.

NOTE: After receiving permission to use the instrument, lab personnel will instruct you in the proper use of the instrument.
REAGENTS
Sodium persulfate solution
Add 50 g of Na2S2O8 to 400 mL of MQ and fill to 500 mL with MQ.
Phosphoric acid solution
Add 59 mL of H3PO4 to 900 mL of MQ and fill to 1 L with MQ.
 
Keep instructions near the carbon analyzer for the quick reference
Start Up Instructions:
1. Check and fill the reagent bottles if they are less than half full. Reagents must be prepared 3 days in advance of use so that they may stabilize.
2. Open valve at the N2 cylinder. Cylinder pressure must be at 300# or above (for 8 hours of analysis or over 500# for an overnight run). The outlet pressure should be at 42#. Askbefore adjusting the outlet pressure. (Proceed through step 6 allowing 5 minutes for N2 to bubble through reagents while moving through steps 3, 4, 5, and 6)
3. Turn on the power on the instrument panel. STANDBY appears in window.
4. Turn on the printer and check the amount of paper.
5. Press SET arial on the keyboard. Press ENTER to step through options until TIME OF DAY appears in the LED window. Enter the time using 24 hour clock format. Press ENTER. SAMPLE PUMP TIME appears in the window. If not at 11 seconds, key in 11 and press ENTER.
6. After the STANDBY message is replaced by READY, check the flow meters. The purge gas flow should be at 6 and the detector flow should be at 5.
7. Press DISPLAY MODE on the keyboard until the light appears next to CALIBRATION CONSTANTS. Press ENTER until ENTER CAL METHOD: 1 FOR TIC, 2 FOR TOC appears in the window. Press ENTER. ENTER IC BLANK appears. Press 0 ENTER. ENTER OC BLANK appears in the window, press 0 ENTER.
8. Press DISPLAY MODE on the keypad until the light appears next to NORMAL ppm C.
9. Prime acid and oxidant pumps by pressing PRIME ACID key 120 arial. Press PRIME OXIDANT key 120 arial and tap the Na2S2O8 one-way valve to clear air bubbles.
10. Press SET SYSTEM CONFIGURATION on keypad. SELECT SECTION 1, 2, 3 appears in the display window. Press 2 ENTER. SAMPLE ID NUMBER is displayed. Press ENTER. SAMPLE STOP NUMBER is displayed. Press 1 ENTER. NUMBER OF REPLICATES appears next. Key in 10 ENTER. Press CLEAR ENTRY on the keypad (this exits you from the configuration sequence).
11. Press the red RUN/STOP button. The instrument will analyze 10 reagent blanks (This will take 80 minutes).
 
Calibration Instructions:
1. After the blanks have run, average the last 3-5 IC mV readings.
2. Average the last 3-5 OC mV readings.
3. Press the DISPLAY MODE key until the light appears next to CALIBRATION CONSTANTS.
4. Press SELECT NEXT DISPLAY until ENTER CAL METHOD: 1 FOR TIC, 2 FOR TOC appears. Press ENTER.
5. ENTER IC BLANK appears in the window. Enter the value from Step 1 above, ENTER.
6. ENTER OC BLANK appears in the window. Enter the value from Step 2 above, ENTER.
7. STD MASS µg is displayed. Key in CAL STD's concentration in µg. This is calculated by multiplying the ppm carbon by the sample loop volume (e.g. 25ppm C X 0.974 g loop = 24.350 µg C injected by the sample loop). Press ENTER.
8. Press ENTER until START THE CALIBRATION SEQUENCE appears in the window. Press the SELECT DISPLAY MODE key twice until the panel light indicates NORMAL MODE.
9. Press SET SYSTEM CONFIGURATION, 1 ENTER. Step through the sequence by pressing ENTER until SAMPLE PUMP is displayed. Press 1 ENTER to enable the sample pump.
10. Continue through sequence by pressing ENTER until SAMPLE LOOP VALVE is displayed. Press 1 ENTER.
11. Continue until AUTOSAMPLER is displayed, press 1 ENTER.
12. Continue until SAMPLE ID NUMBER is displayed, key in 2 ENTER. When STOP SAMPLE NUMBER is displayed, key in 8 ENTER. When NO. REPS PER SAMPLE is displayed, key in 1 ENTER, CLEAR ENTRY.
13. Place three Milli-Q blanks and four CAL STDs on the autosampler. Advance the first Milli-Q vial to the position directly under the needle by pressing the manual advance button at the rear of the autosampler. (Place an empty shuttle on the autosampler a few spaces behind the Milli-Q and CAL STD shuttles to stop the autosampler when the Milli-Q and CAL STD shuttles are removed)
14. Open the valve to the wash station and fill the water reservoir with fresh Milli-Q (you will need to refill to reservoir about every hour).
15. Press the red RUN/STOP button to begin the analysis. (Three Milli-Q and four CAL STDs will take 56 minutes to run)
 
Run Analysis Instructions:
1. After the last printout from the CAL STD, average the last three TOC mV readings of the CAL STDs. Average the three Milli-Q mV readings. Subtract the Milli-Q mV average from the CAL STD average to get the standard average.
2. Press SELECT DISPLAY MODE twice to return to the CALIBRATION CONSTANTS option. Press NEXT DISPLAY until ENTER STANDARD AVERAGE is displayed. Key in the standard average calculated in Step 1 above. Press ENTER. Record the scaling factor in the log book near the machine.
3. Press SELECT DISPLAY MODE until the light appears next to normal.
4. Log all samples into the carbon logbook according to the protocol (see protocol guidelines).
5. Press SET SYSTEM CONFIGURATION, 2 ENTER.
6. SAMPLE ID NUMBER appears in the window, press 9 ENTER.
7. SAMPLE STOP NUMBER appears in the window, key in the last OI sample ID number from the log book ENTER.
8. Advance the vials until the first sample is in position. Check Milli-Q level in the reservoir. The reservoir will need to be refilled about every hour with fresh Milli-Q.
9. Press the red RUN/STOP button.
 
Shut Down Instructions:
1. After the last sample has printed (which should be a Milli-Q sample) press PRINT. Advance the paper from the printer by pressing ON LINE (on printer) and then press FF. Rip off printout and press ON LINE again to return printer to ready status.
2. Turn off the printer. Record analyst, date, and a list of who the samples were run
for on the printout.
3. Turn the POWER switch on the instrument face off.
4. Close the valve on the N2 cylinder.
5. Close the valve on the wash station.
6. Record the date, number of samples ran, analyst, and comments (including who the samples were run for, if reagent bottles were refilled and any adjustments made to the machine).
 
 
More complete information can be found in the Model 700 Operation Manual by OI Corporation.
 
Written by D. H. Lindelof
First revision by S. A. Holloway 3/26/91
Second revision by J. A. Thoyre, M. A. Schmidt 7/11/95
 

 

Protocol Format
Process
Protocol ID
dicdoc_analysis1
Protocol Type
laboratory