Determination of sulfamethoxydiazine in pig feed based on transmittance near infrared spectra

A rapid method for the determination of sulfamethoxydiazine in pig feed was developed using transmittance near infrared spectroscopy in combination with partial least squares calibration. Sulfamethoxydiazine in pig feed was extracted with acetonitrile then the transmittance spectra were recorded directly on the extract. Various spectral pre-treatment methods, including derivative, orthogonal signal correction, multiplicative scatter correction and standard normal variate were compared. The forward interval partial least squares strategy was used to select the variables. Results showed that the suitable wavenumber ranges were 7289–6823 cm−1 combined with 5407–4940 cm−1 and the second derivative was the best pre-treatment method. The multivariable detection limit (MDL) and multivariable quantification limit (MQL) were analysed and utilised as indicators to select the proper calibration sample numbers and the concentration ranges. In accordance with these criteria, 24 samples were appropriate for the wide ra...