1 | Incorrect flow path configuration | Review the flow path configuration by right-clicking on the autosampler tile in the dashboard of the CDS and selecting Modify > Flow Path. Compare it to the hardware configuration. If needed, adjust the configuration accordingly. |
2 | Exceeding maximum volume by multiple DRAW commands | Review the total volume of the DRAW commands and ensure it does not exceed the maximum available volume defined by the analytical head and the loop capillary.
Example: An autosampler equipped with a 100 µL analytical head and loop capillary is run with the following injector program, which triggers “allowed volume exceeded” error: DRAW 50.00 µL from sample … DRAW 60.00 µL from location … INJECT The program triggers the error due to an incorrect total volume of 50.0 + 60.0 = 110.0 µL
Solution: Reduce the volume for one of the DRAW commands: DRAW 50.00 µL from sample … DRAW 50.00 µL from location … INJECT Changed program now leads to the allowed total volume of 50.0 + 50.0 = 100.0 µL |
3 | Exceeding maximum volume due to not considering volume loss via WASH commands | Check if any WASH commands are executed before the DRAW, EJECT, and MIX commands. If so, add an extra 0.7 µL for each WASH command when summing up the volume used by the injector program. WASH commands executed after the DRAW, EJECT, and MIX commands must be excluded from the calculation. If necessary, remove WASH commands or adjust the volumes of other volume-manipulating commands.
Example: The autosampler equipped with a 100 µL analytical head and loop capillary is run with the following injector program, which triggers “allowed volume exceeded” error: DRAW 50.00 µL from sample … WASH needle as specified in the method DRAW 50.00 µL from location … WASH needle as specified in the method INJECT The program triggers the error due to an incorrect total volume of 50.0 + 0.7 + 50.0 = 100.7 µL
Solution: Remove the first WASH command: DRAW 50.00 µL sample … DRAW 50.00 µL location … WASH needle as specified in the method INJECT Changed program now leads to the allowed total volume of 50.0 + 50.0 = 100.0 µL
Solution: Reduce the volume for one of the DRAW commands DRAW 50.00 µL from sample … WASH needle as specified in the method DRAW 49.30 µL from location … WASH needle as specified in the method INJECT Changed program now leads to the allowed total volume of 50.0 + 0.7 + 49.3 = 100.0 µL |
4 | Too large eject volume | Review each EJECT command in your injector program and ensure that the volume defined does not exceed the total volume of the DRAW commands before the EJECT command. Add an extra 0.7 µL for each WASH command listed before the EJECT command. If necessary, reduce the volume specified for the EJECT command.
Example: An autosampler equipped with a 100 µL analytical head and loop capillary is run with the following injector program, which triggers “allowed volume exceeded” error: DRAW 45.00 µL from sample … WASH needle as specified in the method DRAW 45.00 µL from location … WASH needle as specified in the method EJECT 100.00 µL to location … INJECT The program triggers the error due to an incorrect total volume of 45.0 + 0.7 + 45.0 + 0.7 - 100 = -8.6 µL
Solution: Reduce the volume for the EJECT command: DRAW 45.00 µL from sample … WASH needle as specified in the method DRAW 45.00 µL from location … WASH needle as specified in the method EJECT 91.4 µL to location … INJECT Changed program now leads to the allowed total volume of 45.0 + 0.7 + 45.0 + 0.7 – 91.4 = 0 µL |
5 | Insufficient mixing volume | Review each MIX command in your injector program and ensure that the sum of the specified mixing volume and the combined volume of all preceding volume-manipulating commands (DRAW, EJECT, WASH) does not exceed the maximum available volume defined by the analytical head and the loop capillary. If necessary, reduce the mixing volume.
Example: An autosampler equipped with a 100 µL analytical head and loop capillary is run with the following injector program, which triggers “allowed volume exceeded” error: DRAW 25.00 µL from sample … WASH needle as specified in the method DRAW 25.00 µL from location … WASH needle as specified in the method MIX 50.00 µL from seat … INJECT The program triggers the error due to an incorrect total volume of 25.0 + 0.7 + 25.0 + 0.7 + 50 = 101.4 µL
Solution: Reduce the volume for the MIX command: DRAW 25.00 µL from sample … WASH needle as specified in the method DRAW 25.00 µL from location … WASH needle as specified in the method MIX 48.6 µL from seat … INJECT Changed program now leads to the allowed total volume of 25.0 + 0.7 + 25.0 + 0.7 + 48.6 = 100 µL |
6 | High variation in the injection volume across multiple analyses and sequences using the same injector program | Review each DRAW, EJECT, and WASH command and ensure that if fixed (hard-coded) parameters are used, they work well with the entire range of the intended injection volume space. If necessary, adjust the specified volumes or switch to a dynamic option (Maximum or Default) if it better suits your application.
Example: The autosampler is equipped with a 100 µL analytical head and loop capillary. This injector program will normally complete for injection volumes 0 - 25.0 µL and trigger error code 34318 for injection volumes 25.1 - 100.0 µL: DRAW default volume from sample … WASH needle as specified in the method DRAW 25.00 µL from location … MIX 48.6 µL from seat ... INJECT For injection of 30.0 µL sample, the program triggers the error due to an incorrect total volume of 30.0 + 0.7 + 25.0 + 0.7 + 48.6 = 110 µL correctly would be the injection of 25.0 µL sample: 25.0 + 0.7 + 25.0 + 0.7 + 48.6 = 100 µL
Solution: Changing the mix volume to the maximum will increase the permitted maximum injection volume to 73.6 µL, although the mixing volume will depend on the actual injection volume: DRAW default volume from sample … WASH needle as specified in the method DRAW 25.00 µL from location … MIX maximum volume from seat ... INJECT Changed program now leads to the allowed total volume: with 30.0 µL sample: 30.0 + 0.7 + 25.0 + 0.7 + 38.6 = 100 µL with 73.6 µL sample: 73.6 + 0.7 + 25.0 + 0.7 + 0.0 = 100 µL
NOTE: The “maximum volume” parameter will allow the autosampler to use the maximum volume remaining in the analytical head. This means that the mixing volume will depend on the injection volume. When the maximum permitted injection volume is used, the mixing volume will decrease to zero µL (see the last example above). |