Long-wave Near Infrared Research Articles

Determination of amino acid nitrogen in tuber mustard using near-infrared spectroscopy with waveband selection stability

Near-infrared (NIR) spectroscopy was successfully applied to the rapid chemical-free determination of amino acid nitrogen (AAN) in tuber mustard. Moving window partial least squares, combined with Savitzky–Golay smoothing, was used for the waveband selection. Based on the various divisions in the calibration and prediction sets, an effective modeling approach with good stability was proposed. The results confirmed that the long-wave NIR region contains sufficient information for the quantification of AAN in tuber mustard. An appropriate waveband (5874–4258cm−1) located in the combination region of NIR was selected. The validation root mean square error of prediction and the validation correlation coefficients of prediction were 0.380mg/g and 0.962, respectively, both indicating good validation effect and stability. The results provided a reliable NIR model and can serve as valuable references for designing spectroscopic instruments for quality evaluation of tuber mustard.

Short-Wave Near-Infrared Spectroscopy for Rapid Quantification of Acidity of Aviation Kerosene

The application of short-wave near-infrared spectroscopy (SW-NIRS) in acidity of aviation kerosene was de- scribed on the term of chemometrics. This spectral region is interesting because this type of spectrometer reduces costs in comparison with traditional long-wave near-infrared (LW-NIR) instrument. The SW-NIR calibration models of aviation kerosene were established by partial least square regression (PLS). Satisfactory calibration statistics were obtained with a standard error of calibration (SEC) of 0.028 mgKOH/100mL and a standard error of prediction (SEP) of 0.036 mgKOH/100mL. A t-test showed that the NIRS model had an accuracy equivalent to that of GB/T 264-91, which was equal to ASTM D 847, in the analysis of acidity of aviation kerosene. The NIRS method had the advantages of rapid analysis, better repeatability, little simple, and online analysis, etc.