On-line lab-in-syringe cloud point extraction for the spectrophotometric determination of antimony

• Published in: Talanta (Oxford) 2016-02, Vol.148, p.694-699
• Main Authors: Frizzarin, Rejane M., Portugal, Lindomar A., Estela, José M., Rocha, Fábio R.P., Cerdà, Victor
• Format: Article
• Language: English
• Subjects: Antileishmanial drugs; Antimony; Cloud point extraction; Lab-in-syringe; Waters
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2015.04.076

Most of the procedures for antimony determination require time-consuming sample preparation (e.g. liquid–liquid extraction with organic solvents), which are harmful to the environment. Because of the high antimony toxicity, a rapid, sensitive and greener procedure for its determination becomes necessary. The goal of this work was to develop an analytical procedure exploiting for the first time the cloud point extraction on a lab-in-syringe flow system aiming at the spectrophotometric determination of antimony. The procedure was based on formation of an ion-pair between the antimony–iodide complex and H+ followed by extraction with Triton X-114. The factorial design showed that the concentrations of ascorbic acid, H2SO4 and Triton X-114, as well as second and third order interactions were significant at the 95% confidence level. A Box–Behnken design was applied to obtain the response surfaces and to identify the critical values. System is robust at the 95% confidence level. A linear response was observed from 5 to 50µgL−1, described by the equation A=0.137+0.050CSb (r=0.998). The detection limit (99.7% confidence level), the coefficient of variation (n=5; 15µgL−1) and the sampling rate was estimated at 1.8µgL−1, 1.6% and 16h−1, respectively. The procedure allows quantification of antimony in the concentrations established by environmental legislation (6µgL−1) and it was successfully applied to the determination of antimony in freshwater samples and antileishmanial drugs, yielding results in agreement with those obtained by HGFAAS at the 95% confidence level. On-line lab-in-syringe cloud point extraction for the spectrophotometric determination of antimony. [Display omitted] •Automatic Lab-in-syringe cloud point extraction method for antimony determination.•Environmental friendly analytical procedure for determination of antimony.•Fast, precise and reliable procedure for antimony determination.•The method was successfully applied to freshwater samples and antileishmanial drugs.