Alliance 2695 shows poor reproducibility on small-volume injections with 250-µL syringe and 200-µL sample loop - WKB2701

SYMPTOMS

• High %RSD failure while making 5-µL injections on an Alliance 2695 with standard 250-µL syringe and 200-µL sample loop
• One of the area counts in a series of six 5-µL injections is much lower
• System precision passes when making injections at 50 µL, 100 µL, and 200 µL
• Seal pack geometry calibration is successful
• Purge and compression test passes

ENVIRONMENT

• Alliance 2695

CAUSE

• Bad sample loop installed at PM. Suspect poorly connected fittings or a sample loop volume that is much larger than 200 µL.
• Sample loop not configured properly

FIX or WORKAROUND

• Replace the 200-µL sample loop (430001630; TUBE ASSY, SAMPLE LOOP, 200 µL, 2695 [for use with phase II injector assembly])
• Verify the sample loop is configured to the correct volume

ADDITIONAL INFORMATION

The Alliance 2695 had a "Phase II Injector". The cut-over to the phase II injector design began in October 2005, beginning with the following serial numbers:

• Part Number / Serial Number / Type
  • WAT270008 / J05SM4035M / 2695 w/ sample htr/clr
  • WAT270886 / J05SM7373M / 2695 w/o sample htr/clr
• Alternative part number WAT045584 for the "717 SAMPLE LOOP", which is the 200-µL sample loop used on the Alliance 2695 with the original injector assembly