White J G
Upjohn Company, Kalamazoo, Michigan 49001.
Pharm Res. 1994 May;11(5):728-32. doi: 10.1023/a:1018936631642.
A method has been developed to determine the moisture end point in a microwave vacuum dryer using near-infrared spectroscopy (NIR). Dryer studies were conducted in two T.K. Fielder microwave dryers, a Spectrum 65 and a Spectrum 1200. On-line spectra were collected using a NIRSystems Model 5000 Analyzer with a fiber-optic probe. The calibration equation uses absorbances measured at 1410, 1930, and 1630 nm. Moisture values determined on-line with this equation correlate to within 1% of the Karl Fischer results for samples below 6% moisture. The absolute SEP is 0.6% and the average residual is -0.2%. At levels above 6% moisture, the NIR results do not correlate well with Karl Fischer but the moisture curve can be used to assess the homogeneity of the water in the granulation. The combination of qualitative and quantitative information makes it possible to monitor the drying process and to predict consistently the moisture end point in the microwave dryer.
已开发出一种使用近红外光谱（NIR）来测定微波真空干燥器中水分终点的方法。干燥器研究在两台T.K. Fielder微波干燥器（一台Spectrum 65和一台Spectrum 1200）中进行。使用配备光纤探头的NIRSystems 5000型分析仪收集在线光谱。校准方程使用在1410、1930和1630 nm处测得的吸光度。用该方程在线测定的水分值与卡尔费休法测定结果的相关性在水分含量低于6%的样品中在1%以内。绝对标准误差（SEP）为0.6%，平均残差为-0.2%。在水分含量高于6%时，近红外结果与卡尔费休法的相关性不佳，但水分曲线可用于评估制粒中水的均匀性。定性和定量信息的结合使得监测干燥过程并始终如一地预测微波干燥器中的水分终点成为可能。
