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Table 1 Summary of method validation data

From: Targeted CYP2E1 quantification and its correlation to currently acceptable clinical biochemical indices

Parameters YPEIEEK (P1) GTVVVPTLDSVLYDNQEFPDPEK (P2) IS-P1 IS-P2
Linear range 5–100,000 fg/µl 100–12,500 fg/µl NA NA
Linearity r2 = 0.991 ± 0.007 r2 = 0.998 ± 0.001 NA NA
LLOQ 5 fg/µl 100 fg/µl NA NA
Specificity CV = 4.0 ± 0.04 % CV = 15.9 ± 0.42 % CV = 2.42 ± 0.05 % CV = 14.2 ± 0.57 %
Quality control: L M H L M H NA NA
Intra-day
 Accuracy, % 99.2 99.8 98.2 41.0 69.2 70.6 NA NA
 Precision, CV% 3.64 4.79 10.93 55.14 5.32 17.13 NA NA
Inter-day
 Accuracy, % 91.75 105.08 90.09 70.8 82.6 84.14 NA NA
 Precision, CV% 9.76 4.56 0.77 42.54 12.62 20.13 NA NA
  1. The optimized analytical method for CYP2E1 quantification was validated by assessing the linear range, linearity, LLOQ, specificity, intra and inter-group accuracy and precision. IS-P1 internal standard for P1; IS-P2 internal standard for P2; NA not applicable. Coefficient of variation (CV, %) is presented as mean ± standard deviation. Coefficient of variation, means and standard deviations were calculated using the Sigma plot 11.2 software. Overall, the analytical method showed higher sensitivity and specificity for P1 (LLOQ = 5 fg µL−1; CV% = 4.0 ± 0.004) in comparison to P2 (LLOQ = 100 fg µL−1; CV% = 15.9 ± 0.42). Higher intra-day accuracy (L = 99.2 %; M = 99.8 %; H = 98.2 %) and precision (L: CV% = 3.64; M: CV% = 4.79; H: CV% = 10.93) were observed for quantification of P1 in comparison to P2 [(Accuracy) L = 41.0 %; M = 69.2 %; H = 70.6 % / (precision) L: CV% = 55.14; M: CV% = 5.32; H: CV% = 17.13]. Similarly, Inter-day accuracy for P1 (L = 91.75 %; M = 105.08%; H = 90.09 %) showed higher than 90 % accuracy for all levels of QC quantitated while P2 quantification showed slightly lower accuracy (L = 70.8 %; M = 82.6 %; H = 84.14 %) for all levels of QC in comparison to P1. Inter-day precision for quantification of P1 at all 3 QC levels showed CV% < 10 showing that the quantification method was highly precise for P1. P2 showed poor precision (L: CV% = 42.54 %; M: CV% = 12.62 and H: CV% = 20.13 %) for L and H QC levels. Overall, P1 showed higher reproducibility and reliability as representative peptide for CYP2E1 in the optimized targeted proteomic approach