Use of Near-Infrared Reflectance Spectroscopy to Analyze Vitamin Content

Near-infrared reflectance spectroscopy (NIRS) has been used to determine the composition of many products used in animal nutrition. This study sought to determine how best to apply NIRS to analyze the concentration of 11 vitamins in a standard premix. Two methods of regression, stepwise and modified partial least-squares, were used to analyze the results. Stepwise regression showed a confounding effect among various wavelengths and was problematic for use at extreme wavelengths. Modified partial least-squares regression gave more accurate results, as indicated by values of the coefficient of determination in calibration (1.0 for all vitamins) and the coefficient of determination in validation (0.96 to 1.0). Application of NIRS in conjunction with modified partial least-squares regression shows promise as a quick and inexpensive procedure for analysis of vitamin content.