VALIDATION OF SAMPLE PREPARATION PROCEDURES FOR BOTANICAL ANALYSIS

A P-part method was developed to validate the extraction efficiency (a ccuracy) of specific marker compounds from crude herb samples. This me thod has several advantages over the standard addition method of valid ating efficiency. In part 1, recovery optimization, recovery of marker compound is optimized by determining the maximum weight of sample tha t may be extracted in a specific volume of solvent before affecting re covery. The choice of extraction solvent was based on physicochemical parameters of the specific marker compound, In part 2, extraction effi ciency testing and validation, the extraction solvent and optimal samp le weight are used to test and validate extraction efficiency by extra cting and then re-extracting 10 replicate samples of each botanical. T he average recoveries of marker compound from extraction and re-extrac tion are compared by analysis of variance at the 95% confidence level. Extraction is considered 100% efficient if there is no significant di fference between these averages. The solvent and/or conditions used fo r extraction are modified and the efficiency is retested if the averag e recoveries are significantly different. Extraction precision and rug gedness are evaluated from coefficients of variance and by testing the efficiency of several chemically different marker compounds. Levels o f marker compounds are determined by liquid chromatography and by comp arison with peak areas produced by reference standard solutions of kno wn concentration. The method is extremely precise and rugged, making i t a valuable tool for evaluating and validating the efficiency of extr acting marker compounds from crude herb samples.