Fletouris D J, Botsoglou N A, Mantis A J
Aristotle University, School of Veterinary Medicine, Laboratory of Milk Hygiene and Technology, Thessaloniki, Greece.
J AOAC Int. 1995 Jul-Aug;78(4):1024-9.
A rapid spectrophotometric method for determining natamycin in cheese and cheese rind has been developed. Samples are homogenized with acidified aqueous acetonitrile and homogenates are filtered. Natamycin is directly quantitated in filtered extracts on the basis of the characteristic third-derivative trough at 322.6 nm. Additional cleanup of extracts is not required because derivative transformation of the conventional analytical band at around 319 nm eliminates spectral interferences from other compounds. The analysis is simple and can be completed in 6 min. The equipment is easily accessible because most modern spectrophotometers allow instant generation of derivative spectra. The method needs small amounts of solvents and has good analytical characteristics. Overall recovery was 98.4 +/- 0.7%, and linearity was excellent (r = 0.9998) in the range examined (0.5-20 mg/kg). Quantitation and detection-limits were estimated at 0.5 and 0.25 mg/kg, respectively. Precision statistics based on within-day and between-days variations suggest an overall relative standard deviation of 1.4%.
已开发出一种用于测定奶酪及奶酪外皮中纳他霉素的快速分光光度法。样品用酸化乙腈水溶液匀浆，匀浆液过滤。基于322.6 nm处的特征三阶导数谷，直接对过滤后的提取物中的纳他霉素进行定量。由于在约319 nm处常规分析谱带的导数变换消除了其他化合物的光谱干扰，因此无需对提取物进行额外净化。该分析方法简单，可在6分钟内完成。由于大多数现代分光光度计可即时生成导数光谱，设备易于获取。该方法所需溶剂量少，具有良好的分析特性。在所考察的范围内（0.5 - 20 mg/kg），总回收率为98.4 +/- 0.7%，线性良好（r = 0.9998）。定量限和检测限分别估计为0.5和0.25 mg/kg。基于日内和日间变化的精密度统计表明总体相对标准偏差为1.4%。
