[Sources of Uncertainty and Influencing Factors in the Analysis of Volatile Components in Blood Using Headspace Gas...

To use uncertainty as an indicator to evaluate the main factors affecting data quality in the quantitative analysis of 12 volatile components in blood, including ethanol and toluene, and to assess the impact of different quality parameters, such as different hardware platforms on analytical results.

Two established headspace gas chromatography platforms were used following the method specified in Examination Methods for Ethanol, Methanol, n-Propanol, Acetone, Isopropanol and n-Butanol in Blood and Urine (GB/T 42430-2023) for analysis. According to the requirements of Guidance on Quantifying Uncertainty in Chemical Analysis (CNAS-GL006：2019) and Evaluation and Expression of Uncertainty in Measurement (JJF 1059.1-2012), the uncertainty of the whole process of 12 volatile components quantitative analysis such as ethanol and toluene in blood was calculated. The differences of individual uncertainty components and the same uncertainty components across different hardware platforms were compared sequentially, and the results were verified by quantitative analysis of actual samples.

There was no significant difference in the uncertainty components of quantitative analysis of 12 volatile components, whether it was a hardware platform composed of domestic or imported instruments. Among them, the relative standard uncertainty of type A introduced by repeatability tests and analysts ranged from 2.81×10^-3 to 9.28×10^-3; the type B relative combined standard uncertainties introduced by the standard solution and internal standard solution were 5.65×10^-3 to 1.15×10^-2, 4.85×10^-3, respectively, the type B relative standard uncertainties introduced by the calibration curve and equipment were 1.45×10^-2 to 2.47×10^-2 and 5.00×10^-3, respectively. The overall relative combined standard uncertainty of each component ranged from 1.74×10^-2 to 3.07×10^-2.

In the analysis of 12 volatile components in blood, including ethanol and toluene, calibration curve fitting is the dominant source of uncertainty. Reasonable parallel operation can effectively control the uncertainty. The selection of different hardware platforms and other quality parameters does not significantly affect the quantitative results of 12 volatile components in blood.