Derivatization‐free determination of short‐chain volatile amines in human plasma and urine by headspace gas chromatography‐mass spectrometry

Abstract

Background Short‐chain volatile amines (SCVA) are an interesting compound class playing crucial roles in physiological and toxicological human settings. Dimethylamine (DMA), trimethylamine (TMA), diethylamine (DEA), and triethylamine (TEA) were investigated in detail. Methods Headspace gas chromatography coupled to mass spectrometry (HS‐GC‐MS) was used for the simultaneous qualitative and quantitative determination of four SCVA in different human body fluids. Four hundred microliters of Li‐heparin plasma and urine were analyzed after liberation of volatile amines under heated conditions in an aqueous alkaline and saline environment. Target analytes were separated on a volatile amine column and detected on a Thermo DSQ II mass spectrometer scheduled in single ion monitoring mode. Results Chromatographic separation of selected SCVA was done within 7.5 minutes. The method was developed and validated with respect to accuracy, precision, recovery and stability. Accuracy and precision criteria were below 12% for all target analytes at low and high levels. The selected extraction procedure provided recoveries of more than 92% from both matrices for TMA, DEA and TEA. The recovery of DMA from Li‐heparin plasma was lower but still in the acceptable range (>75%). The newly validated method was successfully applied to plasma and urine samples from healthy volunteers. Detected concentrations of endogenous metabolites DMA and TMA are comparable to already known reference ranges. Conclusion Herein, we describe the successful development and validation of a reliable and broadly applicable HS‐GC‐MS procedure for the simultaneous and quantitative determination of SCVA in human plasma and urine without relying on derivatization chemistry.

Engineered Polymersomes for the Treatment of Fish Odor Syndrome: A First Randomized Double Blind Olfactory Study

“…The TMA content was determined as described previously with minor modifications. [ 46 ] In short, calibrator (50 µL) or TMA samples were mixed with internal standard (50 µL) and liberation solution (900 µL, 2 m NaOH/ 0.5 m KCl) in a 20 mL headspace vial and capped directly. Calibration was performed using single point calibration at 500 × 10 −6 m .…”

“…After 3 h of incubation in a 1 × 10 −3 m TMA‐containing buffer, the skin substrate was treated with the gel and incubated for 30 min at 37 °C. The herein used TMA concentrations exceeded those usually encountered in healthy humans (≈5 µ m in human plasma), [ 46 ] to ensure recognition of the distinctive TMA smell by the participants. Perceived odor intensity was rated on a ten‐point odor detection scale, ranging from 0, which equaled the negative control, up to 10, equaling the positive control (Figure 1b).…”

Volatile-Mediated Inhibitory Activity of Rhizobacteria as a Result of Multiple Factors Interaction: The Case of Lysobacter capsici AZ78

“…Additionally, in order to monitor any matrix effects on the detection of amines related to the NA medium, HS vials containing NA spiked with trimethylamine solutions were included in the analysis. Before measurements, both samples and trimethylamine reference standards were treated with 375 µL of 4 M NaOH/1 M KCl (pH 11) solution following the approach of Neyer et al [49].…”

“…Samples and reference standards were measured in parallel by a head space (HP7694, Agilent)-gas chromatograph-flame ionization detector (HP5890, Agilent) (GC-FID). The analytical method used was according to Neyer et al [49], with some modifications. Briefly, the following parameters were applied: HS oven at 70 • C, loop and transfer line at 80 • C, sample loop of 3 mL, injection at 220 • C at 100:1 split ratio; GC oven temperature starting at 40 • C (1 min) raised to 180 • C at 25 • C/min, chromatographic separation on a Rtx ® -Volatile Amine column (60 m × 0.32 mm × 5 µm) (Restek Corporation, Pennsylvania, PA, USA), carrier gas He at 2 mL/min; flame ionization with synthetic air (400 mL/min)/H 2 (43 mL/min) and N 2 (9 mL/min) as make up gas; signal peak width 0.053 min and data rate at 5.000 Hz.…”

Unveiling the Electronic Interaction in ZnO/PtO/Pt Nanoarrays for Catalytic Detection of Triethylamine with Ultrahigh Sensitivity

“…The American Conference of Governmental Industrial Hygienists (ACGIH) proposes a threshold limit of 1 ppm . Chromatography and colorimetric techniques , are the traditional methods applied to detect TEA, which have disadvantages such as time consumption, high cost, and complex operation. Hence, a rapid, accurate, high-sensitivity, and ppb-level limit of detection (LOD) technology is urgently needed.…”