title: Cloud point extraction and diffuse reflectance-Fourier transform infrared spectroscopic determination of chromium(VI): A probe to adulteration in food stuffs.
abstract: 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 λmaxat 540nm. 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 4.02μgmL-1, respectively. Excellent linearity with correlation coefficient value of 0.94 was found for the concentration range of 1-100μgmL-1. At 10μgmL-1the standard deviation for 7 replicate measurements was found to be 0.11μgmL-1. The method was successfully applied to commercially marketed food stuffs, and good recoveries (81-112%) were obtained by spiking the real samples.
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, Chhattisgarh 492010, India.
authors.forename: Swapnil
authors.initials: S
authors.lastname: Tiwari
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, Chhattisgarh 492010, India. Electronic address: debmanas@yahoo.com.
authors.forename: Manas Kanti
authors.initials: MK
authors.lastname: Deb
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur, Chhattisgarh 492010, India.
authors.forename: Bhupendra K
authors.initials: BK
authors.lastname: Sen
mesh_terms: D002857:Chromium / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D004160:Diphenylcarbazide / Q000737:chemistry; D005504:Food Analysis; D057230:Limit of Detection; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D002857:Chromium; C074702:chromium hexavalent ion; D004160:Diphenylcarbazide
keywords: Adulteration; Chromium(VI); Cloud point extraction; DRS-FTIR technique; Turmeric