Infrared spectroscopy for the quality analysis of Tebuthiuron powder and Regain granules

Infrared spectroscopy is a rapid analytical technique that has been successfully applied for the quality assurance and process control in various industries. Consequently, it was thought that infrared spectroscopy may be suitable for the assessment of key quality attributes (moisture and tebuthiuron content) in Regain granules manufactured by Cirrus Ag. Three methods of infrared spectroscopy (two benchtop and one handheld) were trialled for the rapid, non-destructive prediction of moisture content and tebuthiuron content in the Regain samples. Additionally, spectra were collected from samples inside plastic Ziploc bags to determine whether this technique could be used for the in-bag analysis of these analytes. The most accurate results were found using the handheld MicroNIR instrument, with a root mean square error of 0.83% for moisture content and 7.5 mg/g for tebuthiuron content. The prediction results using the benchtop NIR instrument was slightly lower, while the accuracy of models using NIR spectra collected through the plastic sample bag was moderately lower. Additionally, the performance of the handheld MicroNIR instrument was tested on a set of independent samples, with the mean prediction error for tebuthiuron found to be <4 mg/g per sample. This suggests that handheld NIR instruments such as the MicroNIR may be suitable for the rapid, in-situ quality analysis of Regain samples – either during or after the manufacturing process.