Environmental Measurements Facility

User Info

  1. The ICP-OESat EMF serves as a primary elemental analysis instrument for Stanford University community.  Anyone planning to run samples should sign up here on this web site first before bringing samples in for analysis.  First time users should contact lab personnel by email before signing up for analysis. 

  2. Operation: The ICP-OES is operated only by appointed personnel at EMF. No users are allowed to operate the instrument or computer without the approval from the operator.  Please direct any questions to us.

  3. Samples: All samples for analysis must be in aqueous form.  Unknown samples and standard solutions must be free of solid particulates.  Samples should be filtered with a 0.45mm or smaller membrane filters.  Solids in the samples can cause inaccurate readings and clog the line and nebulizer, resulting in longer running time, expensive repairs, replacements, and down time on ICP, which we would like to avoid. Please note that we do not digest samples for users but we may provide information on it and there is a CEM Microwave digester for users to prepare their solid samples for ICP analysis at EMF.

  4. Standard Solutions: The standard solutions should be prepared by the users in the same matrix as the unknown samples if possible to eliminate the potential matrix interferences.  Prepare your standards carefully because it will affect the accuracy of your results. Inaccurate standard solution and contaminated blank can result in inaccurate results for your unknown samples.  Click here for more information on making standard solutions.

  5. Cost: Because the ICP has a high maintenance expense we have to charge users for using it, however, since this is not a commercial lab instrument, the charge is minimal for our users.  Currently, users are billed per time used and the minimum charge is 0.5 hour.  After that the charge increment is 15 min.  Please check this link for current rate.  Users will be also billed for up to 30 min. warming up time plus the actual time used to run samples.  When you sign up for using ICP, a valid PTA number has to be provided online for running samples. 

The ICP operator must be provided with (What you need to prepare):

  • A Blank-this is your matrix solution. This is the solution you use to prepare other solutions. 

  • Standard Solutions—all elements that are going to be measured should be included in these solutions.  This solution should be made with the matrix you use for your unknown samples if possible.  You need to prepare at least 2 standard solutions.  It is preferred to have 3 or 4 concentrations from low to high.  Usually, make a high standard and then do a serial dilution of that solution.  Do 1x, 2x, 4x and/or 8x dilutions will be sufficient for the analysis.  

  • Unknown samples- All unknown samples must be contained in 13X100 mm test tubes or 15 ml Felcon (preferable) tubes, which will fit to the ICP-OES autosampler racks.  For ICP-MS samples, plastic tubes are recommended.  Glass tubes should be avoided.  The tube can be purchased from Fisher Scientific or your preferred vendors.  For your convenience, here are the cat # for buying from Fisher Scientific, 14-956-7A for plastic tubes. Eight(8) ml of samples should be enough.  Please contact us if you do not have enough solution.

All standards and unknown solutions should be arranged based on this template file.  It is best if you can email the file back with your sample information to me before bringing samples for analysis.  This will minimize the errors and also your sample information will be saved on our computer and server for a long time.

If you have any questions making standard solutions, please check with Guangchao Li at gcli@stanford.edu or call 724-3220.

Data: After analysis is completed, users need to come to collect all standard solutions and unknown samples left from the run immediately.  Then, the data will be posted on our website and you will be able to download. Your device needs to be on the Stanford campus network or the Stanford VPN.  Click on http://em1.stanford.edu. Your data file will be listed in your group folder, which is named after your PI's last name. The data filename is made up of your initials and the date your samples are analyzed, e.g. JH060606.xlsx.  After you save the file on your hard drive, the data file can be opened by spreadsheet programs such as Excel.  All data collected from the ICP will be saved for at least a year on our server and the instrument computer.

More information about ICP-AES analysis from EPA.

You can get more detailed information by checking out our FAQ.