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Link to US Geological Survey
Coastal and Marine Geology Program
Woods Hole Field Center

Geochemical Sediment Analysis Procedures, Open-File Report 02-371

SETTING UP AN AUTO RUN

PROCEDURE FOR CHN AUTO RUN
Materials Required:
  • Weighed and Folded Samples
  • Weighed and Folded Standards
  • Folded Blanks
  • Folded Conditioner Samples
  • Micro Forceps
  • Sample Weight Data Sheets
  • Computer
  • CHN Analyzer/printer/autosampler
 Preparation Materials; link to larger image

After the CHN Start-up Procedure, you can now set up an Auto Run for your samples.

Press Auto Run and press #4 to Reset the machine back to Sample #1.

Auto Run key; link to larger image

Manually set sample wheel so the #1 tray space is over the sample drop hole.

 Drop hole in Auto tray; link to larger image

Start entering the Run Sequence - see Excel worksheet.

Enter the sample ID's and weights for samples, standards, and blanks from the Sample Weight Data Sheet.

 Run sequence of Excel; link to larger image

After you have entered the data into the Excel spreadsheet, you can now add your samples to the sample wheel tray in the same order you entered them into the machine.

Use forceps to drop your samples into the autosampler.

 

 Place samples in auto tray; link to larger image
Once these steps are completed, you may hit Start and the machine will begin to analyze your samples.

The machine keeps the standard averages from the previous run in its memory, so once the first 3 K-Factors of the new run have been analyzed, you can manually enter the new averages by pressing Parameters 14 to change the K-Factor Criteria. Enter the new averages of C, H, and N for the 3 runs of the K-factors just analyzed.

Press Parameters again to go back to your Auto Run Sequence - machine will keep analyzing while you change the criteria so nothing is interrupted.

Each new run should have new K-Factor averages within the limit.

Start key; link to larger image

Press Parameters key; link to larger image

Although the auto sampler has only 60 spaces for samples, the machine can hold information for 120 samples.

As a sample is analyzed and the space in the autosampler is made available, you may add your next sample and continue the run - Run 61 in the machine is back to space 1 in the autosampler, Run 62 is space 2, etc.

Drop hole; link to larger image
Constantly check the printout to watch the values after the standards are analyzed to ensure that the machine is functioning properly.
* see Troubleshooting

When the Auto Run is finished, the machine will go into STANDBY and you may proceed with the Shut Down.

If you plan to use the machine the following day or in the near future, you do not need to do the complete shut down process. From STANDBY, press PURGE GAS to purge both the Helium and Oxygen tanks. After the purge is complete, you may leave the machine in STANDBY mode with the furnace on. When you are ready to use the machine again, follow the Warm Start procedure.

 

Check print out; link to larger image


Press Purge Gas key; link to larger image

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