Analytical Variables Affecting Analysis of F₂-Isoprostanes and F₄-Neuroprostanes in Human Cerebrospinal Fluid by Gas Chromatography/Mass Spectrometry

Table 1

Results of quantification of F₂-IsoPs and F₄-NPs in three test CSF samples that have been processed for F₂-IsoPs (IsoP method) or F₄-NPs (NP method) analysis.

	NP method		IsoP method	% of difference for F2-IsoPs^c
	F4-NPs (pg/mL)	F2-IsoPs (pg/mL)	F2-IsoPs (pg/mL)
L-CSF	57.7±5.1 (8.8%)	19.5±0.1 (0.5%)	20.6±0.4 (1.7%)^a	5.2%
M-CSF	109.0±9.9 (9.1%)	56.9±1.7 (3.0%)	55.9±0.9 (1.7%)	1.7%
H-CSF	1023.4±116.7 (11.4%)	141.0±4.0 (2.8%)	85.0±0.8 (0.9%)^b	66.0%

There were three replicates for each CSF sample. Nine CSF samples were processed and analyzed together. Data were presented as mean ± standard deviation (coefficient of variation). Coefficient of variation was the ratio of standard deviation to mean presented as percentage and was used to represent within-run imprecision. ^a𝑝<0.05 (𝑝=0.007 under assumption of equal variance versus values of F₂-IsoPs for L-CSF processed by the NP method). ^b𝑝<0.05 (𝑝=0.001 under assumption of unequal variance versus values of F₂-IsoPs for H-CSF processed by the NP method). ^cThe difference between the mean values of two methods divided by the mean values from IsoP method is calculated and represented as % of difference.