optimizationDuring method optimization the diversity and complexity ofdietary supplements and herbal remedies should be taken intoaccount. Furthermore, the different solubility of the analytesrequired the use of a universal solvent which allowed completeextraction of the compounds to be determined from the variousproducts. According to our experiments, most of the investigatedcompounds were soluble in methanol. TAD was the only exceptionwhich had a poor solubility in MeOH, but was freely soluble in ACN.As a compromise, a 1:1 (v/v) mixture of MeOH and ACN was foundto be an acceptable solvent mixture for all the studied compoundsand it was used for sample extraction.