We offer four packages of analytical procedures, each providing high-quality research-grade element concentration data for specific types of matrices: HF/HNO3 acid dissolution for basaltic rocks; sodium peroxide sinter for granitic rocks; high-pressure bomb dissolution for sediments and ores; and simple "dilute-and-shoot" analyses for natural waters. Previously-digested biological materials may be analyzed, using the waters procedure.
For quality control purposes we request that at least 10 grams of material are submitted for all rock analyses. All samples run using the acid dissolution or sinter digestion packages are also analyzed by the pressed powder XRF method as a quality control measure. We endeavor to ensure the results from ICP-MS and XRF are consistent with each other within our normal operating parameters, and deviant samples are re-analyzed without additional cost. Limits of detection are reported at the 3 sigma background level.
HF/HNO3 Acid Dissolution
This is the standard package for trace element analysis of rocks. Dissolution is carried out in an HF/HNO3 mixture in screwtop Savillex beakers on a hotplate. Calibration is by the method of standard addition, providing a rigorous correction for matrix effects. Elements determined are: all the REE, Hf, Nb, Zr, Ta, Rb, Sr, Ba, Cs, Th, U, and Pb.
The technique is described in Jenner, G.A., Longerich, H.P., Jackson , S.E. and Fryer, B.J., 1990. ICP-MS - A powerful new tool for high precision trace element analysis in Earth Sciences: Evidence from analysis of selected USGS standards. Chemical Geology 83: 133-148.
Sodium Peroxide Sinter Decomposition
For samples containing refractory minerals, such as zircon, which are difficult to dissolve completely in acid, we offer a Na2O2 sinter technique. It is most appropriate for rocks carrying a significant fraction of their trace elements in refractory minerals, such as granites. Internal standards are used to correct for matrix and drift effects. This technique produces data for the REE, Y, Th, Zr, Nb, Ba, Hf and Ta.
This method is described in Longerich, H.P., Jenner, G.A., Fryer, B.J. and Jackson , S.E., 1990. Inductively coupled plasma-mass spectrometric analysis of geological samples: An overview. Chemical Geology 83: 105-118.
High-Pressure Bomb Acid Dissolution
This is a high-pressure bomb acid dissolution technique, particularly suited for use in environmental and mineral exploration studies. Complete dissolution of sulphides and many refractory phases is attained. The technique produces quantitative data for Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Ag, Cd, Sn, Sb, La, Ce, Pr, Nd, Er, Tm, Lu, Pb, Bi, and Th. Environmental studies of toxic metals in sediments and soils, and exploration studies of chalcophile elements in ores are often carried out using this package.
The technique is described in Diegor, W., Longerich, H.P., Abrajano, T. and Horn, I. 2001. Applicability of a high pressure digestion technique to the analysis of sediment and soil samples by inductively coupled plasma-mass spectrometry. Analytica Chimica Acta 431: 195-207.
This package is simple analysis of waters without sample digestion. It is designed to acquire data for a large mass range of elements in natural, saline-poor waters. Detection limits vary from a few ppm to low ppt levels depending on the element. Quantitative data are acquired for 35 elements - Li, Be, B, Mg, Al, Si, P, S, Cl, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, La, Ce, Tl, Pb, Bi, and U. Semi quantitative data are produced for Ti, Br, I and Hg.
We urge clients planning to submit fresh waters to filter (0.45 micron) and acidify samples as soon as they are collected. Acidification ensures that metals are retained in solution. Sample bottles should be cleaned beforehand by soaking in 2 N HNO3 overnight, then rinsed with pure water and air dried in a clean air fume hood. For proper acidification, a one liter water sample should contain 25 ml 8 N HNO3 acid. Clients are strongly encouraged to submit reagent blanks that will enable them to monitor contamination during the sample collection and preparation procedure.
Digested biological samples, i.e. blood, urine, fish, lichen, wines etc. may also be analyzed using this method. Contact us for details.
Present protocol is an updated version of the procedure described in Friel, J.K., Skinner, C.S., Jackson , S.E. and Longerich, H.P., 1990. Analysis of biological reference materials, prepared by microwave dissolution, using inductively coupled plasma mass spectrometry. Analyst, 115: 269-273.
In special circumstances, depending on technician and instrument availability, we undertake special procedures to meet individual client needs. Please contact us to discuss special requests.