近红外光谱定量分析毒死蜱乳油中有效成分的光程选择

近红外光谱分析中光程长度的选择对农药乳油中有效成分的定量分析影响很大。以透射方式采集毒死蜱乳油样本的近红外光谱,透射附件为不同光程(1、2、4和10 mm)的石英比色皿,讨论了光程长度对模型性能的影响。在毒死蜱乳油中加入二甲苯,配制不同梯度浓度样本,采用偏最小二乘法(PLS)建立了毒死蜱的近红外光谱预测模型。结果表明,当采用4 mm光程的比色皿采集光谱时,所建模型最优,模型对预测集样本的相关系数为0.983,预测均方根误差为0.383。通过独立样本检测模型性能,模型的预测值与实测值间无显著差异,表明采用4 mm光程透射附件采集光谱时所建立的模型是准确可靠的。

Nearinfrared spectroscopy quantitative analysis the selection of optical path length for chlorpyrifos emulsifiable concentrate

Selection of path length has a great impact on near infrared spectroscopy(NIR) spectroscopy analysis. A series of experiments to determine the optimum path length for chlorpyrifos in pesticide EC determination was presented using a near infrared instrument with transmission measurement. The samples with different contents of chlorpyrifos were made by adding some dimethylbenzene solvent. NIR transmission spectrum of chlorpyrifos samples were collected with different optical path lengths (1, 2, 4 and 10 mm). Calibration models were established using partial least square (PLS) regression. The results showed that when using 4 mm path length cuvette spectral acquisition,the performance of the model with r= 0.983 and RMSEP=0.383 is optimal. Prediction set samples were used for t-test and the result indicated that there was no significant difference between the actual values and prediction values of the model, which indicate that the model developed using 4 mm path length for collecting spectra was accurate and reliable.