ABSTRACT
The aim of this study was to optimize Fourier transform infrared (FTIR) spectroscopy and multivariate calibrationfor the quantitative analysis of Acid orange 7 (AO-7) and Sudan II (S-II) in blusher products. The calibration andvalidation samples were made by adding known concentrations of AO-7 and S-II in the placebo of blusher cosmeticsproducts. High-performance liquid chromatography equipped with photodiode array detector at 300–650 nm wasused to determine the actual values of AO-7 and S-II. The separation of AO-7 and S-II was performed using C18column at 40oC with mobile phase of acetonitrile-water in gradient elution program. FTIR spectra of evaluatedsamples were scanned using FTIR spectrophotometer equipped with attenuated total reflectance (ATR) samplingtechnique. The correlation between actual values of AO-7 and S-II as determined using high-performance liquidchromatography and FTIR predicted values was facilitated with multivariate calibrations. The selection of calibrationmodels relied on highest r2 and lowest levels of root mean square error of calibration, root mean square error ofprediction, and root mean square error of cross validation. The optimization results showed that FTIR spectra-partialleast square regression (PLSR) using wavenumbers of 3,450–2,400 cm−1 and six factors offered the highest r2 value(r2 > 0.98) and lowest errors. FTIR with ATR technique could be used to predict AO-7 and S-II in blusher product withthe main advantage of its simplicity, rapidity, and minimum sample preparation.
ABSTRACT
The objective of this study was to develop and to validate reversed-phase high-performance liquid chromatography(RP-HPLC) method for the determination of acid orange 7 (AO7) and Sudan II (SII) in blusher products. Separationof AO7 and SII was performed using C18 column (Thermo Synergy Gold 250 mm × 4.6 mm i.d., 5 µm) with mobilephase consisting of acetonitrile-water as a solvent (1:1 v/v) and delivered in gradient manner. The mobile phase wasdelivered at flow rate of 0.9 ml/minute, using column temperature of 40°C. RP-HPLC was validated by assessingseveral performance characteristics which included selectivity, linearity and range, sensitivity, precision, accuracy, androbustness. The developed RP-HPLC was selective for the separation of AO7 and SII. Over concentration of 10.326–41.304 µg/ml (AO7) and 9.967–39.869 (SII), the method was linear with coefficient of correlation (r) >0.999. Themethod was sensitive as indicated by low limit of detection and limit of quantification. The relative standard deviation(RSD) values during intra-assay and inter-assay were lower than those required by RSD Horwitz. The percentageof recovery was within acceptable ranges as required by Association of Official Analytical Chemists method. Thevalidated RP-HPLC method has been successfully applied for the analysis of AO7 and SII in commercial blusherproducts, and both AO7 and SII were not detected in the tested samples.