低浓度多元糖混合水溶液体系的近红外分析

利用近红外光谱分析了葡萄糖、果糖、单糖和蔗糖的二元以及三元混合溶液。水在近红外区域的吸收十分强烈,近红外光谱分析更多应用于干燥的或者低水分的样品,而不适用于新鲜的果蔬样品。文章试图将近红外用于水溶液体系的分析,在不回避水的强干扰因素的情况下,探讨如何改进分析手段,优化分析结果。实验中样品浓度分布在0·01~0·25mol·L-1的范围。对于物理化学性质都比较接近的低浓度单糖溶液,通过比较它们在不同组分中的近红外谱图,特别是C—H,O—H等基团的近红外吸收在不同条件下的变化,以及选择不同波数区间或者全谱建立分析模型对于分析结果的影响,优化波数区间的选择,结合化学计量学优化计算,以获得质量较高的校正模型,改善分析结果,克服水的影响。

Analysis of Multi-Component Sugar Aqueous Solution in Low-Concentration by Near-Infrared Spectrometry

Near infrared spectrophotometry was used to determine the concentrations of one, two and three-component sugar aqueous solutions. However, this method was always applied to dry or low moisture products and was not practicable for fresh fruits and vegetables because of the strong absorption of water in near infrared region. In this paper, the authors applied NIR method to aqueous solutions and discussed how to enhance the sensitivity. In aqueous solution systems, concentration of each individual sugar was in range of 0.01-0.25 mol x L(-1). Different calibrations and predicted results were gotten and compared to each other when full spectra or significant spectra regions were considered. By selecting relevant spectra regions due to important structural information to overcome the disturbance from absorption of water, calculations could be optimized and predicted results of concentrations were more accurate regarding the standard error of calibration (SEC) and standard error of prediction (SEP).