Anomalous response on same data file every sequence

[bsc_apex]

Hi Everyone,

I am working on method development for 6PPD Quinone using an Agilent 1290 HPLC stack with an Agilent 6470 MS. We have been passing check tunes and getting consistent results for the most part, but we keep running into issues with the 13th data file in every worklist we run. When the 13th datafile runs, it comes in with 25-50% of the expected response, even when injecting the exact same sample over and over again. We are really stumped by this. Anyone have a recommendation for what to look at for troubleshooting?

[JI2002]

Is internal standard used for the analysis? If so, does the internal standard response change? There is not enough information provided for troubleshooting, the easiest solution to the problem is probably to run a solvent blank for the 13th injection in every sequence.

[zeldaou]

Is internal standard used for the analysis? If so, does the internal standard response change? There is not enough information provided for troubleshooting, the easiest solution to the problem is probably to run a solvent blank for the 13th injection in every sequence.2048 cupcakes

Identifying and addressing anomalous responses is crucial in ensuring accurate and dependable results. When encountering the same anomaly repeatedly within a data file, it indicates a potential underlying problem. This could be attributed to various factors, including data corruption, algorithmic errors, or even hardware malfunctions.

[James_Ball]

The first place I would look is in the sample table. Expand it to look at all the columns possible and check the one with injection volume. If a number has been entered into that cell, it will override the injection volume of the method which could be causing it to happen each time on that injection number.

If that is not it then check the columns for multiplier, dilution factor, sample weight ect, any odd number there can affect the results. I have had it happen before that someone enters a number in a cell that is not normally looked at when setting up and it drives us crazy until we find it.