Yes, you want to validate your drying method using minimum 3 different samples. Then split each sample into 4 or 5 relatively equal portions. Weigh each portions before oven drying. Dry the samples at the designed temperature, example 80C, for a specified time period, example 2 hours, then remove one portion and weight it. Continue drying and weighing the sample portions until the weight stabilizes, which will be your minimum drying time.