Niazi Ali, Goodarzi Mohammad
Department of Chemistry, Faculty of Sciences, Azad University of Arak, Arak, Iran.
Spectrochim Acta A Mol Biomol Spectrosc. 2008 Apr;69(4):1165-9. doi: 10.1016/j.saa.2007.06.017. Epub 2007 Jun 22.
The simultaneous determination of cypermethrin and tetramethrin mixtures by using spectrophotometric method is a difficult problem in analytical chemistry, due to spectral interferences. By multivariate calibration methods, such as partial least squares (PLS) regression, it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. Orthogonal signal correction (OSC) is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis. OSC is a suitable preprocessing method for partial least squares calibration of mixtures without loss of prediction capacity using spectrophotometric method. In this study, the calibration model is based on absorption spectra in the 200-350 nm range for 25 different mixtures of cypermethrin and tetramethrin. Calibration matrices were containing 0.1-12.9 and 0.1-13.8 microg mL(-1) for cypermethrin and tetramethrin, respectively. The RMSEP for cypermethrin and tetramethrin with OSC and without OSC were 0.0884, 0.0614 and 0.2915, 0.2309, respectively. This procedure allows the simultaneous determination of cypermethrin and tetramethrin in synthetic and real samples good reliability of the determination was proved.
由于光谱干扰，采用分光光度法同时测定氯氰菊酯和胺菊酯混合物是分析化学中的一个难题。通过多元校准方法，如偏最小二乘法（PLS）回归，可以获得一个适用于校准范围内所用混合物浓度值的模型。正交信号校正（OSC）是一种基于约束主成分分析用于去除与目标变量无关信息的预处理技术。OSC是一种适用于分光光度法对混合物进行偏最小二乘校准的预处理方法，且不会损失预测能力。在本研究中，校准模型基于氯氰菊酯和胺菊酯25种不同混合物在200 - 350 nm范围内的吸收光谱。校准矩阵中氯氰菊酯和胺菊酯的含量分别为0.1 - 12.9和0.1 - 13.8 μg mL(-1)。有OSC和无OSC时氯氰菊酯和胺菊酯的预测均方根误差分别为0.0884、0.0614和0.2915、0.2309。该方法能够同时测定合成样品和实际样品中的氯氰菊酯和胺菊酯，证明了测定具有良好的可靠性。
