Ion pair–dispersive liquid–liquid microextraction prior to UV-Vis spectrophotometry for determination of trace amounts of total antimony

Environmental context This study provides a simple and sensitive method for measuring trace amounts of antimony. This measurement is needed as antimony is known as a toxic element in environmental samples. Antimony is widely distributed in the environment and can come into contact with humans. Here the ultraviolet–visible spectrophotometry is combined with dispersive liquid–liquid microextraction. The approach can help monitor antimony pollution and protect environmental and human health. Rationale Trace antimony (Sb) has environmental and health risks, so sensitive and selective analytical methods for its determination in diverse samples is a necessity. Existing techniques often require complex procedures or expensive instrumentation, highlighting the need for a simple, efficient and cost-effective method. Methodology A novel ion pair–dispersive liquid–liquid microextraction (IP-DLLME) procedure was developed. SbIII was oxidised to SbV in hydrochloric acid (HCl) using potassium permanganate (KMnO4) to form the extractable hexachloroantimonate ion (SbCl6−). The ion-pair with methyl violet was subsequently extracted into chlorobenzene. Key parameters, including solvent type and volume, methyl violet concentration, acid concentration, extraction time and ionic strength, were systematically optimised. Results Under optimised conditions, the method exhibited a linear calibration range of 5–300 ng mL−1, with a limit of detection of 4.1 ng mL−1, a limit of quantification of 12.3 ng mL−1 and an enrichment factor of 270. Recovery studies demonstrated good tolerance toward common coexisting ions. The method was successfully applied to natural water, bottled orange juice, kohl and safety match samples. Discussion The proposed IP-DLLME method provides a practical, selective and sensitive approach for routine determination of trace Sb in environmental and consumer products. Its simplicity, high enrichment factor and minimal reagent consumption make it suitable for widespread application. Future studies may focus on extending this approach to detect other toxic metal ions and coupling with alternative detection techniques such as ion pair chromatography and ion selective electrodes.