Mixedmicelle-mediated extraction for simultaneous trace determination of rhodamine B and rhodamine 6Gby spectrophotometry coupledwith the partial least squares regressionAuthor(s): Kaihui Huang, Jian Deng, Canhui Hu, Dan Chen, Ni Xiao, Saiqin Ju
In this work, a novel method has been developed to simultaneously determine trace amount of rhodamine B (RhB) and rhodamine 6G (Rh6G) by spectrophotometry coupled with partial least squares regression. A modified cloud point extraction (CPE) method, which utilized a combination of the nonionic surfactant, Triton X-114, and the anionic surfactant, sodium dodecyl benzene sulfonate (SDBS), as the extractant, was used to preconcentrate RhB and Rh6G from sample solutions. The extraction conditions, such as concentration of surfactants, electrolyte concentration, and pH on the CPE were investigated and optimized using a single-factor method followed by a L9 (34) orthogonal array design (OAD). The maximum absorption wavelengths for RhB and Rh6G are 558 and 533 nm, respectively; linearity is obeyed in the range of 3.4-550 and 4.0-500 ng mL-1 with detection limits of 1.2 and 1.8 ng mL-1, and the root mean square errors of prediction (RMSEP) are 9.166 and 11.699 ng mL-1, respectively. The proposed method has been applied successfully to simultaneously determine trace amount of RhB and Rh6G in paprika, hotpot ingredients, and river water samples with the recoveries of 86.8Â111.8%.