Optical matching of near infrared reflectance monochromator instruments for the analysis of ground and whole wheat

Eight near infrared (NIR) reflectance monochromator instruments in Australi a have been optically matched (standardised) in order that reflectance spec tra can be obtained when the same sample is measured on any of the instrume nts which are as similar as reflectance spectra obtained by re-packing the same sample on one instrument. This means that data from the different inst ruments can be merged to produce calibrations based on a larger number of m ore diverse samples than would be available to any one laboratory, without the need for the actual samples to be moved around the country. In turn, th e resulting spectral library and calibrations can be shared. Two methods of standardisation of this type of instrument have been previously reported f or ground samples. One method utilises 30 sealed powdered samples of divers e types in order to correct for both slope and bias while the other require s only a single sealed sample to correct for bias. The results of standardi sation, using the set of 30 samples and using a single ground wheat, confir ms that the single sample standardisation works as well as that performed u sing the 30 samples. In addition, an extension of the single sample method using whole grain samples is reported. The results confirm that the single sample method can be successfully used to optically match NIR reflectance m onochromator instruments of the same brand.