University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Classification: Reference Material -> USGS -> SGR-1 -> Shale

Citations 1

"Determination Of Mercury In Geological Materials By Continuous-flow, Cold Vapor, Atomic Absorption Spectrophotometry"
Anal. Lett. 1987 Volume 20, Issue 6 Pages 899-908
Kennedy, K.R.;Crock, J.G.

Abstract: The sample (0.1 g) is heated at 110°C for 3 h with HNO3 - 25% Na2Cr2O7 and the cooled digest is passed to a continuous-flow manifold for mixing first with air and NaCl - hydroxylammonium chloride - H2SO4 (reducing and complexing agent) and then with 10% SnCl2 solution (to reduce Hg(II) to Hg0). Vapor was released in a phase separator and passed to a Model 457 atomic absorption spectrometer (Thermo Jarrell Ash) equipped with a 6-mA Hg hollow-cathode lamp and operated at 253.7 nm (0.7-nm slit) without background correction. The sample and reagent flow rates and reagent composition were adjusted to obtain max. absorbance for solution containing 10 µg L-1 of Hg. For 10 µg L-1 of Hg, the coefficient of variation was <1.2% (n = 16), and for analysis of SGR-1 standard shale, the mean value was 170 ppb with coefficient of variation of <6%. The detection limit was 20 ppb of Hg, which could be lowered by using a larger sample or smaller dilution volume The only significant interference is from Se.
Mercury Spectrophotometry Interferences Phase separator Reference material