Grant G A, Frison S L, Yeung J, Vasanthan T, Sporns P
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5.
J Agric Food Chem. 2003 Oct 8;51(21):6137-44. doi: 10.1021/jf034118l.
Successful quantification of the glucose produced by enzyme hydrolysis of starch was achieved by a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) protocol, using sorbitol as an internal standard. The starch contents measured by MALDI-TOF MS of corn starch, fiber-enriched oat flour derivatives, oat and barley flours, and barley flour/corn starch composites were evaluated in comparison to a widely accepted and validated method of starch determination, which relies on enzyme colorimetry (EC). The average starch content measured in a series of corn starch samples of different masses was 93 and 101% for EC and MALDI-TOF MS, respectively, values that represent the estimated purity of the sample. There was an agreement of 99% between the starch contents determined by the two analytical methods for complex flour-derived samples. Starch values estimated by MALDI-TOF MS consistently showed a greater degree of variability than those determined by EC, but this limitation was readily compensated by rapid acquisition of multiple mass spectra. This study is the first to report the quantification of glucose by MALDI-TOF MS, and it offers new perspectives into the potential utility of MALDI-TOF MS as a definitive tool for monosaccharide analysis and rapid starch determination in complex samples.
采用基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）方法，以山梨醇作为内标，成功实现了对淀粉酶水解产生的葡萄糖的定量分析。通过MALDI-TOF MS对玉米淀粉、富含纤维的燕麦粉衍生物、燕麦粉和大麦粉以及大麦粉/玉米淀粉复合物中的淀粉含量进行了测定，并与一种广泛接受且经过验证的淀粉测定方法（酶比色法，EC）进行了比较。在一系列不同质量的玉米淀粉样品中，EC法和MALDI-TOF MS法测得的平均淀粉含量分别为93%和101%，这些数值代表了样品的估计纯度。对于复杂的面粉衍生样品，两种分析方法测定的淀粉含量之间的一致性为99%。MALDI-TOF MS估计的淀粉值始终显示出比EC法测定的值更大的变异性，但通过快速采集多个质谱图，这一局限性很容易得到弥补。本研究首次报道了用MALDI-TOF MS对葡萄糖进行定量分析，为MALDI-TOF MS作为复杂样品中单糖分析和快速淀粉测定的权威工具的潜在应用提供了新的视角。
