Analytical Notes
Agilent Vapor Generation Accessory VGA 77 and VGA 77P User’s Guide 69
Additional Notes
If arsenic and selenium are both to be determined from the same
sample, determine selenium first and avoid KI in samples or
standards. You can then determine arsenic after the KI reduction
step and any other appropriate treatment (such as the addition
of urea if excess nitric acid is present).
For the determination of arsenic and selenium in many practical
samples containing high concentrations of metals such as copper,
iron or nickel, fewer interferences have been observed using
0.3% w/v NaBH
4
solution concentration (rather than 0.6% w/v).
Use of the lower reductant concentration may be less sensitive.
You can minimize interferences of transition metals such as
cobalt, copper, iron, and nickel on arsenic and selenium by
preparing samples in 6-7 M HCl. With lower acid concentrations,
greater inter-element interferences are present.
Co-precipitation methods using lanthanum compounds have also
been found to be useful.
References
1 Smith, A.E., ‘Interferences in the determination of elements that
form volatile hydrides with NaBH
4
using AAS and Ar/H
2
flame.’,
Analyst, May, 1975, 100, 300-306
2 Determination of tin by hydride generation AA, 1992, October,
No. 107
Additional References
The following references are recommended:
Spectroscopy, 1985, Vol 1 (0), 60
Appl. Spectrosc., 1985, Vol 39 (1), 48
Jiri Dedina and Dimiter L. Tsalev, Hydride Generation Atomic
Absorption Spectrometry. Published by John Wiley and Sons,
Edited by J.D. Winefordner. ISDN 0 471 953644
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