Turbidimetric determination of sulfate in rainwater employing a LED based photometer and multicommuted flow analysis system with in-line preconcentration

Journal of the Brazilian Chemical Society

Zárate, Néstor¹  Pérez-Olmos, Ricardo¹  Universidad del País Vasco, Bilbao, Spain¹  Universidade de São Paulo, Piracicaba, Brazil¹  Reis, Boaventura Freire dos¹ 

关键词: sulfate;    turbidimetry;    multicommuted flow analysis;    LED-based photometer;    ion exchange resin;    rainwater;   

DOI  :  10.1590/S0103-50532011000600002

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

In the present work, an automatic procedure for turbidimetric determination of sulfate in rainwater, based on the multicommuted flow analysis approach, is proposed. The photometer set-up was developed at the laboratory, and includes: a LED (λ = 420 nm), a long pathlength flow cell (100 mm), and a photodiode. A preconcentration step is included in order to improve sensitivity. After establishing the adequate operational conditions, the proposed procedure presented the following useful features: a linear response ranging from 0.1 mg L-1 up to 2.0 mg L-1 sulfate, a detection limit (3σ criterion) of 0.04 mg L-1 sulfate, a relative standard deviation of 1.5% for 0.5 mg L-1 sulfate solution (n = 7), barium chloride consumptions of 17.0 mg per determination, and waste generation of 7.3 mL per determination. Accuracy assessment was achieved by applying the paired t-test between results obtained using the proposed procedure and ICP-OES and showed that there is no significant difference at 95% confidence level.

【 授权许可】

Unknown