| Author | Message | ||
     Tony Davies (td) Moderator Username: td Post Number: 248 Registered: 1-2001 |
Hello Gretchen, Welcome to the group! You were correct to start a new thread; we wish everyone would. It can get quite confusing when peole are providing answers to two questions in the same thread! Karl Norris developed a method to measure small concentrations of talc. He had samples in vials which he shook before measuring them and repeated this 10 times (Karl please correct me if that's not correct) for each sample and averaged the results. Of course you have to do the same for the calibration and test samples. The improvement should approach /sqrt n. What is your requirement for the sep? I am a little worried about variations in the size distributions of your flow agent and the carrier. Small particles have a larger surface area to mass ratio so variation in the size distribution could lead to a larger error when you calculate your results on a weight basis. Best wishes, Tony | ||
| Gretchen Karcher (gkarcher) New member Username: gkarcher Post Number: 2 Registered: 2-2011 |
Hello, I figured I'd make a new thread since new posts don't seem to move a thread up and I don't want my question missed. I'm new to the boards, but I'm working on trying to figure out a way to check the blend uniformity of a fine powdered flow agent onto a granule. I've made calibration curves but I can only trust my results to 0.5% and I'm only blending 1-2% flow agent onto my granules, so that's quite an error. My calibration curves are based on samples in small glass jars on the integrating sphere after being blended for a certain amount of time. But I'm having trouble trusting that the fines are dispersed properly. I've thought of simply tapping all the fines to the bottom of the jar for measuring but I'm not sure how reliable that is. These samples can't be dissolved easily, so that's out of the question. Do any of you have any suggestions on how best to measure this more accurately? I've seen papers out there on uniformity but most of them have to do with testing after tableting and my final product is just the granule with the flow agent. Any help would be greatly appriciated. Thanks, Gretchen |