Absolute correction factor
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We prepared a standard sample by ourselves; there are 6 different substances in it, and we need to determine their correction factors. I have a question for the experts here: why are the correction factors different each time we analyze the same sample 5 times, with the same injection volume? How should we select the correction factor from these 5 sets of data? Thank you!
Remove outliers and take the average. The samples are not parallel; that’s how it’s done. It is likely a sampling issue that causes slight differences in the amount of sample introduced!
The injection technique should be considered first; after improvements, abnormal data should be identified and removed, and then the average value should be taken
If capillary split injection is used, it is necessary to determine the absolute correction factor for the sample components; poor stability is normal in such cases, and it results in much worse performance compared to full injection using a packed column； But after adjusting the shunt ratio, there will be an improvement; when the shunt ratio is set to 30:1, giving it a try might result in a much better outcome.
How to calculate the relative correction factor in gas chromatography
Method for calculating the relative correction factor: F = (AI * MS) / (AS * MI), where AI is the peak area of the internal standard, MS is the mass of the component being analyzed, AS is the peak area of the component being analyzed, and MI is the mass of the internal standard
Determining the absolute correction factor requires high standards regarding sampling techniques; when the amounts of sample injected are not consistent, the response values at the detector will certainly differ, and as a result, the measured absolute correction factors will also vary.
The determination of absolute correction factors is only useful when studying certain issues, but it has no significance in the actual measurement of samples. This is because the absolute correction factor determined today will have some error when used the next day. In quantitative analysis using the external standard method, a pair of standards is required for each sample analyzed. If several samples are analyzed back to back, those samples can share the same pair of standards, meaning the calibration is done as the analysis proceeds. Therefore, determining absolute correction factors holds no practical value.
How much is the difference in non-parallelism you’re talking about, and is it within the range allowed by the instrument? ? ? If the difference is acceptable, the average value will do. Personal opinion