Simultaneous Spectrophotometric Quantification of 2-Nitrophenol and 4-Nitrophenol in Binay Mixtures Based on Partial Least Squares Method: Comparison Analysis of Five Types of Data Sets

In this study, simultaneous quantification of 2-nitrophenol and 4- nitrophenol in their binary mixtures was investigated spectrophotometrically. Since the signals of analytes were highly overlapped, multivariate partial least squares (PLS) technique was proposed to analyze the data. PLS method makes the analysis possible without the need for separation of analytes by tedious separation procedure or using expensive instrumentation techniques such as chromatographic methods. Both 2-nitrophenol and 4- nitrophenol possess acid-base property and it was required to investigate the effect of pH on the FOM of the calibration. Therefore, at three pH conditions, the calibration processes were evaluated and the results showed the best FOM and the least root mean squares error of prediction (RMSEP) for both analytes were achieved for the augmented data at 3.45 and 8.95 of pHs where only neutral or anionic forms of analytes were present in the solution. The analytical sensitivity, limit of detection, R2 and RMSEP were 108.3 ppm-1, 0.08ppm, 1.00, 0.04 ppm and; 163.2 ppm-1, 0.06 ppm, 0.9999, 0.04 ppm for 2-nitrophenol and 4-nitrophenol, respectively.