Fundamental study on the performance of the modified Meixner test to detect the natural toxin α-amanitin

Abstract

α-Amanitin (AMA) is primarily a natural toxin component of poisonous mushrooms such as Amanita virosa (AV). In this study, we examined the performance of the Meixner test to detect AMA in various solvents. Although we referred to previous publications, there was a lack of information about the method of the Meixner test, such as the amount and concentration of each reagent. Therefore, in this study, we developed our own procedure named the modified Meixner test. Samples with AMA were prepared in distilled water (DW), urine, and serum. In addition, mushroom component extraction samples were also obtained. As a result of the modified Meixner test performed according to our procedure, a positive reaction was observed in samples with 200 μg/mL AMA in DW. On the other hand, the detection sensitivity decreased when the concentration of hydrochloric acid used in this study was lowered. Positive reactions were also obtained in samples with 200 μg/mL AMA in urine and serum, whereas AMA at concentrations of less than 100 μg/mL was negative in all solvents. Boiling (100°C, 30 min) of each sample did not affect the test results. The sensitivity was decreased in samples prepared in serum and urine to which hemoglobin was added, and AMA at concentrations of less than 200 μg/mL indicated a negative reaction. Three out of five samples with AMA extracted from AV showed a positive reaction with this test. The modified Meixner test showed an AMA detection sensitivity of ≥100 μg/mL, except for hemolytic and hematuria samples.