Overcoming the schlieren effect in flow injection spectrophotometry by introduction of large sample volumes: determination of chloride in the electrolyte of lead-acid batteries
A flow injection spectrophotometric system is proposed for determining chloride in lead-acid battery electrolyte by using the displacement reaction between mercury(II) thiocyanate and chloride in a medium containing iron(III). The employment of a large sample volume was effective to avoid refractive index gradients in the central part of the sample zone. Sulfate interference was studied and the correlation between the chemical equilibria involved and the transient signals was used to develop a strategy for chloride quantification. Samples containing from 2.2 to 3.7 mol L-1 of sulfuric acid can be determined by using the same analytical curve, without matrix interference or any previous treatment. The detection limit and the relative standard deviation were estimated in 0.37 mg Cl- L-1 (99.7% confidence level) and 1.6% (n = 10), respectively. The sampling rate was 45 h-1. Recoveries between 95.9 and 108% were obtained for additions of chloride (2.00 to 8.00 mg L-1) in the samples.
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Format: | Digital revista |
Language: | English |
Published: |
Sociedade Brasileira de Química
1997
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Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50531997000600010 |
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