Tin - Agilent Technologies VGA 77 User Manual

Analytical Notes

Tin

The best results for tin will generally be obtained from solutions
prepared in 1% w/v tartaric acid. Also, a study
addition of L-cysteine greatly improves tin determination by hydride
generation. The L-cysteine reduces metal interferences and improves
precision and sensitivity. Some improvement in calibration linearity
has also been noted.
The concentration of acid pumped into the VGA 77 is also critical in
tin determinations, and the analytical signal will be severely
depressed at concentrations higher than 0.5 M. (See Page 57 'Acid
Concentration'.)
When determining tin using the AA technique, it is essential to
determine tin at the 286.3 nm wavelength and 0.2 nm slit since this
will provide the best combination of analytical sensitivity and
dynamic range. The 235.5 nm line commonly used for flame and
furnace AA gives very poor sensitivity and the 224.6 nm line shows
very little increase in analytical response above approximately
0.3 absorbance.
Reductant container:
Acid container:
Sample
Alternative method
Reductant container:
Acid container:
Sample
68
NaBH
NaOH 0.5% w/v
0.5 M HCl
1% Tartaric acid
controlled pH (2.0 to 3.0)
2
NaBH
NaOH 0.1% w/v
D.I. H
1% w/v Tartaric acid
1% w/v L-cysteine
Agilent Vapor Generation Accessory VGA 77 and VGA 77P User's Guide
(2)
has shown that the
0.6% w/v
4
0.5% w/v
4
O
2