Ultrasound-assisted treatment of coconut water samples for potentiometric stripping determination of zinc

Journal of the Brazilian Chemical Society

Munoz, Rodrigo A. A.¹  Kolbe, Matias¹  Oliveira, Pedro V.¹  Siloto, Rita C.¹  Angnes, Lucio¹  Universidade de São Paulo, São Paulo, Brazil¹ 

关键词: potentiometric stripping analysis;    zinc;    copper;    coconut water;    ultrasound-assisted treatment;    ultrasonic bath;   

DOI  :  10.1590/S0103-50532007000200025

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

This work describes the application of potentiometric stripping analysis (PSA) at mercury film electrodes for zinc determination in coconut water. A sample ultrasound-assisted treatment was developed and optimised for the total zinc determination by PSA. One milliliter of sample was treated with 2 mL of 1:1 (v/v) concentrated HCl and H2O2 (30% m/v) mixture in closed (4 mL) vessels under sonication (in ultrasonic bath), followed by a thermal step (in a boiling bath, for 15 min). This methodology was optimised for total zinc determination and was validated by graphite furnace atomic absorption spectrometry (GFAAS) analysis utilizing the sample without any treatment. The limit of detection obtained by the proposed PSA method was 1.35 µg L-1 (applying 45 s of preconcentration). Attempts to evaluate the amount of copper in the same sample show that the content of this metal is lower than the detection limits of both techniques, GFAAS and PSA (0.030 µg L-1 after 600 s of preconcentration) at gold film electrodes.

【 授权许可】

Unknown