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Instrumentation   User Fees   ICP-MS Applications

Laboratory Technician Alexandra Franco in front of the Agilent 7900 Inductively Coupled Plasma Mass Spectrometer Dionex ICS-2500 Ion Chomatograph

For inquires regarding analytical capabilities, sample preparation, or scheduling and pricing, contact Ben Perkins: Telephone: (503) 725-3387 Fax: (503) 725-3025 email: rperkins@pdx.edu Mailing Address Portland State University  Department of Geology Cramer Hall 17 P.O. Box 751 Portland, OR 97207-0751   FedEx / UPS Street Address Portland State University  Department of Geology  Cramer Hall 17 1721 SW Broadway  Portland, OR 97201

The lab houses the following instrumentation:

• Agilent 7900 Inductively Coupled Plasma Mass Spectrometer (ICP-MS)

• Agilent 720 Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES)
  

• Dionex ICS-2500 Ion Chromatograph (IC)

• Beckman Coulter DU 730 Spectrometer

• Bruker Hand-held XRF
  

• Milestone Ethos series closed-vessel microwave digester

Laboratory Fee Schedule:

• ICP-MS: Academic Users, unassisted: $60 per plasma hour

• ICP-OES: Academic Users, unassisted: $43 per plasma hour
  

• ICP-MS: Outside Users - Contact Lab to discuss your needs

• IC: Academic Users, unassisted: $20 per pump hour

• Assistance (including sample preparation, training): $50 per hour

ICP-MS Applications:

ICP-MS can generate high-quality trace-level (sub-ppb) concentration data for elements with a wide range of atomic masses from ⁶Li to ²³⁸U. The best results are obtained for elements that have ionization potentials well below that of the carrier gas (Ar, 15.8 eV) and that are free of isobaric interferences. Our current setup precludes analyzing anything other than solutions. Analyses of soils, rocks, and other solids thus requires that samples be dissolved (e.g., via strong acid digestion). Solution samples submitted for analysis should be free of solids and elevated concentrations of organic compounds. Ideally, they should be in a matrix of 1-3% HNO3. Other matrices, including HCl, may be problematic in terms of signal response (e.g., viscosity differences affecting nebulization efficiencies, matrix components affecting plasma chemistry or inducing space charge effects) and interferences. For these reasons, accurate analyses of solutions that are not in a dilute HNO3 matrix require matrix matching with standards and or use of standard addition calibration. Reagents used for sample preparation should be doubly distilled or ultrapure where possible. Samples that have high concentrations (> ppm) of analytes should be diluted. A minimum of 10 ml should be submitted for analysis.

 Users need to provide:

Standards: Ideally these will be prepared from single- or multi-element commercial stock solutions. Typically, we utilize 3 to 6 external standards that bracket expected sample concentration range. In addition, we recommend that internal standards be utilized to account for variations in instrumental response as the analysis proceeds (drift). Internal standards (IS) are elements (e.g., Y, In, Bi) that would have negligible concentrations in sample and that do not cause isobaric interferences with analytes; they are added to all blanks, standards, and samples and the analyte:IS ratio is used to calibrate.

Blanks: Procedural blanks should be prepared by the same method used to prepare the unknowns. If the unknowns have not been processed by any digestion method, the blank would be diluted acid similar in concentration and character to that in the unknowns. Blanks will be run initially to check the cleanness of sample preparation procedures.

Quality Control Samples: These are samples of known concentrations, but prepared separately from (ideally with different stocks and by different people) calibration standards and are used to check the accuracy of the calibration and to track instrumental drift. Commercial QC samples are available.