ICP-OES is used to analyze liquid samples for elemental composition. Matrix-matched standards and a method blank are made and analyzed to produce a calibration curve. Samples are introduced into the system using an autosampler. It will take approximately a half hour to prepare the machine for analysis. Each sample and calibration standard will take approximately 1.5 minutes per element being analyzed, plus one minute for washing (all automatic). Preparing the instrument to shut down will take approximately twenty minutes. A minimum of 5 ml is needed for any analysis, and more is needed if many elements are being analyzed, up to a maximum of 14 ml in the sample tube.

Principle

ICP-OES is used to analyze liquid samples for elemental composition. Matrix-matched standards and a method blank are made and analyzed to produce a calibration curve. Samples are introduced into the system using an autosampler.

Equipment

  • PerkinElmer 2100 DV
  • Chiller
  • Argon tank
  • Nitrogen tank

Reagents

  • DI water
  • 10 ppm Mn solution
  • ICP standard solutions (prepared according to “Preparing ICP Standards SOP”)
  • 5% nitric acid

Procedure

  1. Turn on the chiller.
  2. Turn on the ICP-OES.
  3. Open the “gas” valve on the argon tank.
  4. Open the valve on the nitrogen tank.
  5. Stretch the red-red and black-black tubes over the peristaltic pump and close the clamps.
  6. Open the WinLab32 software on the computer and wait for green check marks to appear in the boxes.
  7. Empty and refill the wash beaker with DI water.
  8. Click the “plasma” button and toggle the “plasma” button to “on”
  9. Place the sampler needle into the 10 ppm Mn solution.
  10. Once the plasma has ignited, go to Tools – Spectrometer Control – Align view – OK
  11. If analyzing for elements at very low concentrations, choose the axial view; otherwise choose radial.
  12. Once the view alignment is complete, enter the highest value in the log book along with the method to be used and number of samples. If the number is below 1,000,000 for the radial view, something is wrong. Run 5% nitric acid through the machine for fifteen minutes, then try to align the view again.
  13. Place the sampler needle back in the autosampler holder.
  14. Open the method that you are going to use (file – open – method) or create a new method. Click on the “method editor” button to open the method window.
  15. Check that in the “calibration” tab, the concentrations of standards listed are what you plan on using. If not, change the method.
  16. Open the Sample Information File editor and save.
  17. Input the sample IDs and autosampler locations. Remember that the large spots are 1-8, and the blank and standards will be in at least 9-12.
  18. Include a check sample for every 12-20 unknowns.
  19. Click the “autosampler” button to bring up the analysis control window.
  20. In the data tab, “open” the save location and enter the name of your file.
  21. In the analysis tab, click “Calibrate” to run the blank and standards to create the calibration curve.
  22. If the calibration completes without problems, click “analyze samples”. If the calibration had problems, attempt to solve them and calibrate again. If you have performed this method before and it has not had problems in the past, you can click “analyze all” to move directly into the sample analysis after the calibration.
  23. Estimate how long it will take to complete your samples, and return at that time to begin shutdown procedures.
  24. When all samples have been analyzed:
  25. Place the sample needle in the bottle of 5% nitric acid and allow to flush for ten minutes.
  26. Place the sample needle in the needle holder so it is in the beaker of DI water (refilled if necessary) and allow to flush for ten minutes.
  27. Turn off the plasma by clicking the same toggle button that turned it on.
  28. Close the argon tank and the purge gas (nitrogen) tank.
  29. Turn off the ICP-OES and the chiller.
  30. Open the clamps on the peristaltic pump and take the tubing off so it doesn’t prematurely flatten.
  31. Close the WinLab32 software.
  32. If the samples do not contain hazardous material and have a neutral pH (6-8), empty the remaining sample down the drain. If the pH is not in that range or they contain hazardous material, empty them into the waste bucket so they can be neutralized later.