scholarly journals Determination of N-Nitrosamines by Gas Chromatography Coupled to Quadrupole–Time-of-Flight Mass Spectrometry in Water Samples

Separations ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 3 ◽  
Author(s):  
Benigno José Sieira ◽  
Inmaculada Carpinteiro ◽  
Rosario Rodil ◽  
José Benito Quintana ◽  
Rafael Cela
Keyword(s):  
Mass Spectrometry ◽  
Environmental Protection Agency ◽  
Ion Trap ◽  
Solid Phase ◽  
Classical Method ◽  
Tap Water ◽  
Time Of Flight ◽  
The United States ◽  
Mass Analyzer

An analytical method based on high-resolution quadrupole–time-of-flight (QToF) mass spectrometry has been developed as an alternative to the classical method, using a low-resolution ion trap (IT) analyzer to reduce interferences in N-nitrosamines determination. Extraction of the targeted compounds was performed by solid-phase extraction (SPE) following the United States Environmental Protection Agency (USEPA) -521 method. First, both electron impact (EI) and positive chemical ionization (PCI) using methane as ionization gas were compared, along with IT and QToF detection. Then, parameters such as limits of detection (LOD) and quantification (LOQ), linearity, and repeatability were assessed. The results showed that the QToF mass analyzer combined with PCI was the best system for the determination of the N-nitrosamines, with instrumental LOD and LOQ in the ranges of 0.2–4 and 0.6–11 ng mL−1, respectively, which translated into method LOD and LOQ in the ranges of 0.2–1.3 and 0.6–3.9 ng L−1, respectively. The analysis of real samples showed the presence of 6 of the N-nitrosamines in influent, effluent, and tap water. N-nitrosodimethylamine (NDMA) was quantified in all the analyzed samples at concentrations between 1 and 27 ng L−1. Moreover, four additional nitrosamines were found in tap and wastewater samples.

scholarly journals Determination of Chlormequat in Fruit Samples by Liquid Chromatography-Electrospray-Mass Spectrometry/Mass Spectrometry

2001 ◽  
Vol 84 (6) ◽  
pp. 1903-1908 ◽  
Author(s):  
Rocio Castro ◽  
Encarnación Moyano ◽  
Maria Teresa Galceran
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Ion Trap ◽  
Solid Phase ◽  
Ion Pair ◽  
Mass Analyzer ◽  
The European Union ◽  
Fruit Samples ◽  
Mass Spectrometry Mass Spectrometry

Abstract An ion-pair liquid chromatography-mass spectrometry/mass spectrometry method was developed for the determination of chlormequat in fruit samples. A solid-phase extraction cleanup procedure with C18 cartridges was used. Sample preparation was simple and the achieved detection limit (0.03 mg/kg) and quantitation limit (0.08 mg/kg) were below the maximum residue levels legislated by the European Union. The chromatographic separation was performed by using a C8 column and heptafluorobutyric acid as ion pair reagent. The detection was conducted with an electrospray source and an ion trap as a mass analyzer. The reproducibility of the method gave good run-to-run (8–9%) and day-to-day (9–13%) precision values, and its applicability to the determination of chlormequat in pears and grapes, purées, and pear, apple, and grape juices was demonstrated.

scholarly journals Determination of Se4+ in Drinkable Water by Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry

2000 ◽  
Vol 83 (5) ◽  
pp. 1082-1086 ◽  
Author(s):  
Maurizio Guidotti
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Tap Water ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Relative Standard ◽  
Drinkable Water

Abstract A method was developed for the selective determination of Se4+ in drinkable water by solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS). Se4+ was selectively derivatized to ethane, 1,1′-selenobis by reaction with sodium tetraethylborate, extracted by the SPME fiber, and determined by GC/MS. Both headspace (HS)–SPME and direct SPME were studied. The method requires only a few milliliters of sample and 20 min for completion. At 2.0 μg/L concentration, the relative standard deviation was 10.1% for HS–SPME and 9.1% for direct SPME. For HS–SPME, the theoretical detection limit was 81 ng/L and 166 ng/L for direct SPME. The recovery rate was 95%. The method was used to determine Se4+ in 10 tap water samples.

scholarly journals Determination of 2-Propenal Using Headspace Solid-Phase Microextraction Coupled to Gas Chromatography–Time-of-Flight Mass Spectrometry as a Marker for Authentication of Unrefined Sesame Oil

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Ahmad Rois Mansur ◽  
Tae Gyu Nam ◽  
Hae Won Jang ◽  
Yong-Sun Cho ◽  
Miyoung Yoo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Soybean Oil ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Time Of Flight ◽  
Sesame Oil ◽  
Headspace Solid Phase Microextraction ◽  
Flight Mass Spectrometry

Ascertaining the authenticity of the unrefined sesame oil presents an ongoing challenge. Here, the determination of 2-propenal was performed by headspace solid-phase microextraction (HS-SPME) under mild temperature coupled to gas chromatography with time-of-flight mass spectrometry, enabling the detection of adulteration of unrefined sesame oil with refined corn or soybean oil. Employing this coupled technique, 2-propenal was detected in all tested refined corn and soybean oils but not in any of the tested unrefined sesame oil samples. Using response surface methodology, the optimum extraction temperature, equilibrium time, and extraction time for the HS-SPME analysis of 2-propenal using carboxen/polydimethylsiloxane fiber were determined to be 55°C, 15 min, and 15 min, respectively, for refined corn oil and 55°C, 25 min, and 15 min, respectively, for refined soybean oil. Under these optimized conditions, the adulteration of unrefined sesame oil with refined corn or soybean oils (1–5%) was successfully detected. The detection and quantification limits of 2-propenal were found to be in the range of 0.008–0.010 and 0.023–0.031 µg mL−1, respectively. The overall results demonstrate the potential of this novel method for the authentication of unrefined sesame oil.

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