تعیین thiophanate متیل با استفاده از طیف جذب UV بر اساس رگرسیون خطی چندگانه

As one worldwide used agent for fungi control in the fruit and vegetable field, thiophanate-methyl has been constituted a significant health risk. To determinate thiophanate-methyl, the method using UV absorption spectra based on multiple liner regression is used. Principal absorption wavelengths related closely with thiophanate-methyl ethanol solution are confirmed through analyzing the absorption spectra of thiophanate-methyl. Utilizing multiple linear regression, mathematical model between absorbance obtained from fourteen absorption wavelengths and thiophanate-methyl concentration is established. The result shows concentrations between the predicted values and measured values are well coincident and the related coefficient is 0.9853 over the concentration range 2–35 ppm.

Pesticides are used in farming on fruit and vegetable to increase yields and product quality. Benzimidazole fungicides as systemic pesticides are widely used in agriculture, floriculture, and fruit farming for the control of a wide range pathogens [1]. As one worldwide used agent for fungi control, thiophanate-methyl is one component of the benzimidazolic family. The use of thiophanate-methyl has constituted a significant health risk [2] and [3]. Therefore, the determination of thiophanate-methyl residue is of great importance. Thiophanate-methyl can be analyzed by different detection technologies, such as gas chromatography, gas chromatography tandem mass spectrometry, high performance liquid chromatography and so on [4], [5] and [6]. However, the apparatus used in these technologies are very expensive, and in addition, the apparatus operation and analysis process are complicated. So it is necessary to attempt to explore an inexpensive and simple determination method of the thiophanate-methyl. The component and quantity of matter can be determinated through the UV spectra caused by the absorption of molecular or ion of the matter. Multivariate statistical methods are frequently used in exploratory data analysis to obtain environmental knowledge. Spectroscopic method based on multivariate statistical methods is most widely used for matter determination due to the excellent limit of detection. Therefore, the technique combining spectroscopy and multiple liner regression was used widely by researchers in the latest years [7] and [8]. In the present work UV absorption spectra based on multiple liner regression for determination of thiophanate-methyl in ethanol solution is explored. Thiophanate-methyl is detected through analyzing UV absorption spectra.

In this study, UV absorption spectra of thiophanate-methyl ethanol solution have been investigated. The suitable wavelengths which thiophanate-methyl has the strongest absorption relative to other wavelengths is selected for determination of thiophanate-methyl concentration. In order to obtain the concentration from the absorbance data at selected wavelengths, mathematic model between the absorbance and concentration based on multiple linear regression is established. In the concentration range of 2–35 ppm the predicted values show good agreement with measured values and the correlation coefficient between them is 0.9853. Along with the rapid development of the LED and fiber technology, the cost and the character of UV LED and fiber is inexpensive and steady respectively. So the present method can be applied in the rapid determination system based on the narrow-band LED and fiber.