Troubleshooting

Overloaded Sample (> 8000 RFUs)

• Overloaded peaks can lead to poor data as the ABI software cannot accurately track and size the peaks. Also leads to spectral overlap.
• SOLUTION: Increase dilution factor for problematic dye. Ideal signal is between 300-3000 RFUs.

Spectral Overlap

• Here, the BLUE dye is overloaded (>8000 RFUs) to the point that it is "pulling up" signal in the GREEN (2000 RFUs) and YELLOW (1000 RFUs) ranges. You must be careful to recognize these other peaks as false artifacts of the high BLUE signal.
• SOLUTION: Increase dilution factor for the problematic dye. Ideal signal is between 300-3000 RFUs.

Capillary Failure

• Example: failing standard

• Example: clogged capillary

• SOLUTION: Have sample rerun on different capillary
  If reruns do not improve results, your samples may need cleaning prior to future runs.

 

Poor Capillary Performance

• SOLUTION: Have sample run on different capillary
• If problem is systemic, it indicates that the capillary array is getting old and needs to be changed.

No or Very Low Signal

• PCR failure (bad DNA or Taq)
• Too low a dilution
• SOLUTION: Decrease dilution factor. Try New PCR conditions.

Example of Good Run on ABI 3100