|
||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||
ICP-MS LaboratoryContact: David Szymanski Applications The Department of Geological Sciences operates a Micromass (now part of Thermo Fisher Scientific, Inc.) Platform Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The Platform has a hexapole collision cell, which minimizes interferences caused by argon molecules (e.g. 40Ar 35Cl+ on 75As+). The Platform ICP-MS is capable of analyzing 74 elements, either as single elements or in multi-element analysis, with high precision and sensitivity. The analyses can be qualitative or quantitative. The Platform ICP-MS is located in the Food Safety and Toxicology building on the MSU campus in a clean laboratory. The clean environment of the room complements the high sensitivity of the instrument in being able to analyze low level concentrations (ppt). Applications of ICP-MSICP-MS instruments are becoming common in analytical laboratories because of their versatility. In a few minutes, the ICP-MS can produce high quality data for elements with wide range of atomic masses, from 6Li to 238U. The best results are obtained for elements that have ionization potentials lower than those of the carrying gas (Ar, 15.8 eV) and that are free of isobaric interferences. The most common applications for ICP-MS are in biological, environmental, geological, and industrial fields. The following is a modest list of materials that have been analyzed by ICP-MS. Archeological Applications: artifacts (e.g. ancient ceramics, bronze mirrors) and raw materials Biological Applications: Animals: blood, bones, feathers, feces, hair, human breath, milk, red cells, serum, shells, stomach contents, teeth, tissues, urine, zooplankton. Plants: barks, broccoli, fertilizers, fruits, garlic, grass, leaves, mushrooms, roots, tobacco, tea, tree rings, wood. Foods: beverages, food packaging, juices, milk, metabolites, rice flour, sea food, wine. Earth Science Applications: fossils, minerals, meteorites, rocks, soil, waters. Environmental Applications: atmospheric deposits (wet, dry), brines, car exhaust particles, coal fly ash, dust, gases from landfills, incinerator wastes, organic waste, oil pollution, paint, snow, sludge, washing powders. Forensic Science: glass, illicit drugs and plants, soils, paint, metals. Industrial Applications: alloys, automobile catalytic converters, ceramics, dyes, glass, lab gloves, nuclear industry products, paint, paper, petroleum based products, plastic, rare earth element compounds, steel, silica, superconductors, sulfides. Analytical FeesThe joint X-ray Fluorescence and ICP-MS Laboratories at MSU offer a variety of analytical services, including elemental packages for rock and soil samples (Option 1 below). The following schedule shows estimated fees. Additional discounts may be given for large numbers of samples or in-house sample preparation. Fees are subject to change at any time. Prices reflect a normal turn-around time of about one (1) month. Rush orders may require additional charges. Please consult lab manager(s) before officially quoting any prices: Tom Vogel (vogel@msu.edu) and Dave Szymanski (szyman16@msu.edu). 1. Geological (rock and soil) Samples Sample Preparation: All samples are analyzed as glass disks, prepared by fusion of finely-ground rock powders with lithium tetraborate. Samples may be submitted as powders or in bulk. Submit a minimum of 8 grams powder or 30 grams whole rock. Sample preparation fees for any type of elemental analysis are as follows:
*Submitted sample powders should be fine enough so they are not “gritty” when rubbed between sheets of paper. Re-powdering of gritty samples will require an additional charge. Users may also request to prepare their own samples at MSU, subject to a $2.00/sample materials charge. Major and Trace Element Packages (per sample):
*A minimum charge of $250 (academic) and $500 (commercial) will apply for all geological analyses involving LA-ICP-MS. This cost reflects the minimum time to tune the instrument, run standards, and data processing.
2. ICP-MS (solution) Samples Samples must be free of solids and organic compounds, and in a matrix of 1-2% HNO3. A minimum of 10 mL should be submitted for each sample. Standard solutions spanning the range of concentrations of elements of interest must be provided. If standards are not provided and/or concentrations are known, additional sample preparation charges will apply (see below):
NOTE: All self-operator rates apply to users that prepare samples and standards at MSU and have sufficient training to set-up/run samples using the auto-sampler, manual sample introduction or laser ablation equipment. Training is provided for users that will use the instruments regularly over a longer period of time (typically 6-12 months or longer). 3. LA-ICP-MS Samples Based on the relative complexity of analyses (number of ablations, standardization, data processing, etc.) rates will vary for solid sample introduction. The following rates are estimates only. Please contact the lab manager for further pricing. The minimum fee reflects protocol development and data processing.
Sample Preparation and StandardsThe Platform ICP-MS is equipped with a variety of sample introduction systems that allow the analyses of solid, aqueous and gas samples. The most common means of sample introduction are pneumatic nebulization of aqueous liquids via a concentric nebulizer and laser ablation of solid samples. Reagents used for the sample preparation should be double distilled or ultra pure. The high purity acids reduce contamination and background levels in the instrument. Total dissolved solids of solutions should be less than 0.1% (the total dissolved solids is the ratio of the sample weight to the solution volume). The solutions to be run in the ICP-MS should be 1% - 2% HNO3. Sample preparation is responsibility of the user. Always discuss the sample preparation procedure with the lab manager to make sure that the procedure is compatible with the ICP-MS. SOLUTION SAMPLE PREPARATION 1. Standards There are two types of standards that are used in solution ICP-MS. One set of standards includes those solutions prepared from single or multi-element standards that are commercially produced. The second set of standards is known as SRM (standard reference material). SRMs are samples with well-defined compositions (working values) from analyses by many different laboratories. The user should provide a set of at least 4 standards for each run that have concentration range similar to that expected from the unknowns. These standards will be used to generate the calibration curves from which the composition of the unknown samples will be inferred. The user should discuss the number and type of standards most appropriate for the analysis with the Lab Manager. For best results, the standards should have a similar matrix to the unknowns and prepared by the same method. If samples and standards are not matrix-matched, the accuracy of results may be compromised. If the composition of the sample is completely unknown, a qualitative scan must be run prior to the preparation of the standards. 2. Blank solution The user should provide a procedural blank. This blank 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 of similar characteristics to those of the unknowns. The procedure blank will be the first solution to be run to check the cleanness of the sample preparation procedure. If the blank produces unacceptably high counts, the analyses will not proceed. To avoid wasting samples, use only high purity reagents in all the stages of sample preparation. We need to keep the Platform ICP-MS as clean as possible to be able to reach low levels of detection (ppt-ppq). 3. Calibration Common calibration strategies for ICP-MS analyses are internal standards, external standard calibration, standard additions, or isotope dilution. 3.1. Internal standards 3.3. Standard Addition 3.4. Isotope dilution LASER ABLATION SAMPLE PREPARATION In general, one of the largest benefits of laser ablation (LA) ICP-MS is that sample preparation is usually minimal, as long as the sample is relatively homogenous or the region of interest can be identified in the sample (e.g. minerals in thin section). Consult with lab manager for any special sample preparation required for specific types of samples. Sample Introduction Systems1. Autosampler 2. Concentric nebulizer 3. Laser Ablation 4. Direct Injection Nebulizer 5. Ultrasonic Nebulizer and membrane desolvator 6. Micro-Concentric Nebulizer 7. V-Groove Nebulizer 8. Inert Sample Introduction System 9. Hydride Generator Top
|
||||||||||||||||||||||||||||||||||||||||||||