Stochastic Dynamic Electrospray Ionization Mass Spectrometric Quantitative Analysis of Metronidazole in Human Urine

Abstract

The study reports quantification of metronidazole (MTZ) in clinical human urine employing our innovative stochastic dynamic equation D”SD =2.6388.10-17.(<I2>–<I2>). There are direct analysis without presence of internal standard, using ultra-high accuracy nano-electrospray ionization (ESI) mass spectrometry (MS), quantum chemistry and chemometrics, respectively. The linear calibration D”SD =f(conc.) equations are obtained for concentration range 2.5 to 25000 ng.(mL)-1 of spiked urine samples, examining analyte MS ions at m/z 171.0998, 172.0718, 172.04081, 213.1463, 181.0722 and 151.1114, respectively. There is achieved exact coefficient of linear correlation (|r|=1) between theory and experiment of ion at m/z 172.04081. The major challenge to quantify MTZ in urine sample is that it stabilizes cations [M+H]+ of two tautomers, which equilibrium varies drastically within the standard linear calibration dynamic range. The fragmentation patterns depend on analyte tautomers and it unambiguous assignment in multicomponent samples with complex sample matrix effect (SME) is unable to be made without mediation to an independent physico-chemical law. To solve the problem, herein, is used, again, above equation, which is designed a bridge between quantitative and multidimensional structural analytical chemistry, when is used complementary with Arrhenius’s quantum chemical diffusion parameter (DQC.) There is achieved |r|=0.98 of D”SD=f(DQC’) examining tautomeric molecular and fragment ions of MTZ.