Cloud point extraction and diffuse reflectance-Fourier transform infrared spectroscopic determination of chromium(VI): A probe to adulteration in food stuffs

•Environmentally benign probe for determination of Cr(VI) in food samples.•Simple method with good results in terms of excellent linearity and recovery range.•Low limit of detection and quantification with high-sample throughput, is obtained.•The method developed is cost effective and rapid.•Meets the present day challenge of green chemistry need.

A new cloud point extraction (CPE) method for the determination of hexavalent chromium i.e. Cr(VI) in food samples is established with subsequent diffuse reflectance-Fourier transform infrared (DRS-FTIR) analysis. The method demonstrates enrichment of Cr(VI) after its complexation with 1,5-diphenylcarbazide. The reddish-violet complex formed showed λmax at 540 nm. Micellar phase separation at cloud point temperature of non-ionic surfactant, Triton X-100 occurred and complex was entrapped in surfactant and analyzed using DRS-FTIR. Under optimized conditions, the limit of detection (LOD) and quantification (LOQ) were 1.22 and 4.02 μg mL−1, respectively. Excellent linearity with correlation coefficient value of 0.94 was found for the concentration range of 1-100 μg mL−1. At 10 μg mL−1 the standard deviation for 7 replicate measurements was found to be 0.11 μg mL−1. The method was successfully applied to commercially marketed food stuffs, and good recoveries (81-112%) were obtained by spiking the real samples.