For the flavanoid analytic AV-51-0010, it is crucial that hexamethylenetetramine (FLUKA 52709) is 'fresh' (not too old). Then it is crucial that at the beginning the dissolving of the extract in the hexahethylenetetramine is done very very thoroughly (we are using an ultrasonic bath for this purpose), until absolutely no dry extract is left and visible (otherwise, it will decrease the content with this photometrical method).

Огромное спасибо.