Franklin & Marshall College Franklin & Marshall College

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X-ray Laboratory

 The X-ray lab contains two major research instruments, a PANalytical 2404 X-ray fluorescence vacuum spectrometer equipped with a PW2540 X-Y sample handler capable of dealing with 168 individual samples and a 4kW Rh super sharp X-ray tube. The lab also has a PANalytical X'Pert PRO X-ray diffractometer equipped with a 15-position sample changer and a ceramic Cu X-ray tube. Both instruments are available for contract work. Please contact for details concerning cost per analysis, turn around time, etc.

The personnel who handle day-to-day operation of the X-ray instrumentation are Dr. Stan Mertzman, the Earl D. Stage and Mary E. Stage Professor of Geosciences, Steve Sylvester, Research Specialist, and Karen Mertzman, senior lab technician.

XRD and XRF in Brief - for more detailed instructions see links to the left.

X-ray Diffraction                                                                                                                       A PANalytical X'pert Pro x-ray diffractometer is used by students and faculty in the Departments  of Earth and Environment, Chemistry and Physics.  Examples of student and faculty XRD research  include identification of minerals in rocks, soils and lake sediments, characterizing nanoparticles and the properties of synthetic double chain salts.

X-ray fluorescence - sample preparation for major element analysis:
Crushed rock powder (0.4000 +/- 0.0001 grams) is mixed with lithiumtetraborate (3.6000 +/- 0.0002 grams), placed in a platinum crusible and heated with a meeker until molten. The molten material is transfered to a platnium casting dish and quenched. This produces a glass disk that is used for XRF analysis of SiO2, Al2O3, CaO, K2O, P2O5, TiO2, Fe2O3, MnO, Na2O and MgO.

Working curves for each element are determined by analyzing geochemical rock standards (Abbey (1983) and Govindaraju (1994).) Between 30 and 50 data points are gathered for each working curve; various elemental interferences are also taken into account. Results are calculated and presented as percent oxide. 

Ferrous iron titration and Loss on Ignition                                     The amount of ferrous Fe is determined by titration using a modified Reichen and Fahey (1962) method. XRF determines total iron as Fe2O3. Loss on ignition is determined by heating an exact aliquot of the sample at 950C for one hour. 


Preparation for XRF trace element analysis
Trace element analysis is accomplished by weighing out 7.0000 grams + /- 0.0004 of whole rock powder and adding 1.4000 grams +/- 0.0002 of high purity Copolywax powder, mixing for 10 minutes, and pressing the sample into a briquette. Data are reported as parts per million (ppm) for Rb, Sr, Y, Zr, Nb, Ni, Ga, Cu, Zn, U, Th, Co, Pb, Sc, Cr, V, La, Ce, and Ba. Working curves for each element are determined by analyzing geochemical rock standards, data for which has been synthesized in Abbey (1983) and Govindaraju (1994). Between 30 and 50 data points are gathered for each working curve; various elemental interferences are also taken into account. The Rh Compton peak is utilized for a mass absorption correction for region one elements.

Important                                                                                                                          Always keep in mind that the original rock/mineral powder must be crushed so that ALL of the sample passes through a clean 80 mesh sieve screen. Do NOT use Tungsten Carbide grinding vessels if at all possible.

References
Abbey, S., 1983, Studies in "Standard Samples" of silicate rocks minerals 1969-1982: Geological Survey of Canada Paper 83-15, pp. 1-114.

Bennett, H. and Oliver, G.1992, XRF Analysis of Ceramic, Minerals and Allied Materials, John Wiley & Sons, LTD (ISBN 0 471 93457 7 (cloth)) 298pp.

Boyd, F.R., and Mertzman, S.A., (1987): Composition of structure of the Kaapvaal lithosphere, southern Africa: In: Magmatic Processes - Physicochemical Principles, B.O. Mysen, Ed., The Geochemical Society, Special Publication #1, pp. 13-24 . (Contains description of XRF methodology)

Govindaraju, K. 1994: 1994 Compilation of Working Values and Sample Description for 383 Geostandards: Geostandards Newsletter, Vol. 18, Special Issue, pp. 1-158.

Hower, J., 1959, Matrix corrections in the X-ray spectrographic trace element analysis of rocks and minerals. Amer. Mineral. 44, pp. 19-32.

Jenkins, R., 1999, X-ray Fluorescence Spectrometry, 2nd ed., John Wiley & Sons, Inc. (ISBN0-471-29942-1 (cloth)) 207pp.

 

Mertzman, S. A., 2000, K-Ar results from the southern Oregon - northern California Cascade Range. Oregon Geology, V. 62, no. 4, pp. 99-122.


Reichen, L.E. and Fahey, J.J., 1962, An improved method for the determination of FeO in rocks and minerals including garnet. U.S. Geol. Surv. Bull. 1144B, pp. 1-5.

 

 on to cutting and crushing >


For further information regarding these techniques please feel free to email Stan Mertzman at or call him at 717-291-3818 or mail questions to him at:

Dr. Stan Mertzman
Franklin and Marshall College
Department of Earth and Environment
P.O. Box 3003
Lancaster, PA 17604-3003

Mail packages to:
Warehouse
Franklin and Marshall College
Attention: Stan Mertzman
415 Harrisburg Pike
Lancaster, PA 17603

Stan's Home Page