I would like to perform a validation on total raloxifene, by using hydrolysis of glucuronides with b glucuronidase. I did the hydrolisis of glucuronides by icubating the samples in a waterbath for 8h but I had a recovery at about 40% in both high and low concentrations. The same result was achieved with 18h of incubation. I have also increased the consentration of the enzyme but the same. What did I do wrong?