Calibration transfer between PDA-based NIR spectrometers in the NIR assessment of melon soluble solids content

in near-infrared (NIR) spectroscopy, the transfer of predictive models betw een Fourier transform near-infrared (FT-NIR) and scanning-grating-based ins truments has been accomplished on relatively dry samples (< 10% water) usin g various chemometric techniques-for example, slope and bias correction (SB C), direct standardization (DS), piecewise direct standardization (PDS), or thogonal signal correction (OSC), finite impulse transform (FIR) and wavele t transform (WT), and application of neural networks. In this study, seven well-known techniques [SBC, DS, PDS, double-window PDS (DWPDS), OSC, FIR, a nd WT], a photometric response correction and wavelength interpolative meth od, and a model updating method were assessed in terms of root mean square error of prediction (RMSEP) (using Fearn's significance testing) for calibr ation transfer (standardization) between pairs of spectrometers from a grou p of four spectrometers for noninvasive prediction of soluble solid content (SSC) of melon fruit. The spectrometers were diffraction grating-based ins truments incorporating photodiode array photodetectors (MMS1, Carl Zeiss, J ena, Germany), used with a standard optical geometry of sample, light sourc e, and spectrometer, A modified WT method performed significantly better th an all other standardization methods and on a par with model updating.