My allelic ladder has my peaks coming up more than four bases apart to the point that my bins do not catch the peaks. The greatest distance I have had is seven units between the peaks. I have a default offset of 0.5 on both the left and right. This becomes a larger problem with the longer loci such as Penta D and Penta E, but can be a problem with even D7. I am using Promega PowerPlex 16HS on an ABI 310 PRISM Genetic Analyzer.
Dear Sir. Concerning your issue about the cause of peak drifting in capillary electrophoresis. The key to producing good separations is to understand the principles underlying the injection, separation and detection of each allele. Unable to generate a matrix due to faint or no peaks Poor capillary electrophoresis (CE) injection. Re-inject the sample. Check the syringe for leakage. Check the laser power. Poor-quality formamide was used. Use only fresh Hi-Di™ formamide. Samples were degraded due to improper storage. Store matrix standards at –30°C to –10°C, protected from light. Do not store in the freezer door or in a frost-free freezer. We recommend using these matrix standards once and then discarding them. Peak heights were too low. Peak heights should be 1,000–4,000RFU for the ABI PRISM® 310 Genetic Analyzer. To increase peak heights, increase injection time or loading volume. Samples were not denatured. Heat-denature samples, and immediately chill on crushed ice or in an ice-water bath before loading the capillary. Denature samples just prior to loading. For more information I think the following below attached files may help you in your analysis:
Thanks
That is unusual. It seems your system is becoming "sluggish".
Have you changed anything lately? Is the sepn. voltage identical?
I would change the buffer solution, the polymer, the formamide even the capillary. I think your capillary is fouled up. How many times/how long have you been using it?
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