scholarly journals Impact of Photolysis and TiO2 on Pesticides Degradation in Wastewater

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 655
Author(s):  
Mohamed H. EL-Saeid ◽  
Modhi. O. Alotaibi ◽  
Mashael Alshabanat ◽  
Murefah Mana AL-Anazy ◽  
Khadijah R. Alharbi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Tandem Mass Spectrometry ◽  
Water Samples ◽  
Animal Health ◽  
Tandem Mass ◽  
Triple Quadrupole ◽  
Chromatography Tandem Mass Spectrometry ◽  
Low Levels

Pesticide residues are harmful to the environment and human and animal health even at low levels because of long-term bioaccumulation. In this study, photolysis was applied to treat three representative water samples: aqueous atrazine and dimethoate solutions as target pesticides, as well as wastewater and agriculture wastewater containing pesticide residue. It was performed using ultraviolet (UV) irradiation at two wavelengths (254 and 306 nm) with exposure times ranging from 2 to 12 h in the presence and absence of a photocatalyst to identify the optimal degradation conditions. Extraction and analyzation process were performed by the Quick Easy Cheap Effective Rugged Safe (QuEChERS) methods and gas chromatography–tandem mass spectrometry with triple quadrupole detector (GC–MSMS/TQD), respectively. Photodegradation increased with an increase in exposure time and the TiO2 catalyst was beneficial for degradation. Both selected irradiation wavelengths were effective, although the wavelength of λ = 306 nm was the most efficient.

scholarly journals Gas Chromatography-Tandem Mass Spectrometry Method for the Selective Detection of Glycols and Glycerol in the Liquids and Aerosols of E-Cigarette, or Vaping, Products

2021 ◽  
Vol 9 ◽  
Author(s):  
José J. Pérez ◽  
Clifford H. Watson ◽  
Benjamin C. Blount ◽  
Liza Valentín-Blasini
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Tandem Mass Spectrometry ◽  
Health Effects ◽  
Tandem Mass ◽  
Spectrometry Method ◽  
Mass Spectrometry Method ◽  
Chromatography Tandem Mass Spectrometry ◽  
Safety Limit

The long-term health effects of using e-cigarette, or vaping, products (EVPs; also known as e-cigarettes, electronic nicotine delivery systems, and vape pens) remain largely unknown. The inhalation of excipients, such as propylene glycol (PG) and glycerin (GLY), may have long-term health effects. In addition to the direct health effects of PG and GLY, glycerin-containing products can be contaminated with toxic ethylene glycol (EG) and diethylene glycol (DEG). To assess this issue, we developed a simple, versatile, high-throughput isotope dilution gas chromatography-tandem mass spectrometry method for quantifying these common excipients and contaminants. The method is applicable to both the liquid contents and machine-generated aerosols of EVPs. Our rigorous method validation demonstrates that the new method is specific, precise, accurate, and rugged/robust. The calibration range is linear from 0.1–7 mg for the excipients and 2.5–1,000 µg for the contaminants. These ranges encompass expected excipients levels in EVP e-liquids and their machine-generated aerosols and the relevant maximum residue safety limit of 1 mg/g, or 0.1% (w/w), for the contaminants. The calculated limits of detection for PG, GLY, EG, and DEG were determined as 0.0109 mg, 0.0132 mg, 0.250 µg, and 0.100 µg, respectively. The method was applied to the aerosol emissions analysis of 141 EVPs associated with the 2019 lung injury outbreak, and found typical levels of PG (120.28–689.35 mg/g of aerosol) and GLY (116.83–845.96 mg/g of aerosol) in all nicotine-containing products; PG (81.58–491.92 mg/g of aerosol) and GLY (303.86–823.47 mg/g of aerosol) in 13% of cannabidiol (CBD) products; PG (74.02–220.18 mg/g of aerosol) and GLY (596.43–859.81 mg/g of aerosol) in products with neither nicotine nor CBD; and none detected in tetrahydrocannabinol (THC) products. No products contained glycol contaminants above the recommended maximum residue safety limit.

scholarly journals Multiresidue Determination of Pesticides in Fruit and Vegetables by Gas Chromatography/Tandem Mass Spectrometry

2001 ◽  
Vol 84 (4) ◽  
pp. 1209-1216 ◽  
Author(s):  
Miguel Gamón ◽  
Concha Lleó ◽  
Amparo Ten ◽  
Francisco Mocholí
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Tandem Mass Spectrometry ◽  
Chemical Ionization ◽  
Fruit And Vegetables ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Low Levels ◽  
Multiresidue Determination

Abstract Pesticide residues in fruit and vegetables were determined by gas chromatography/tandem mass spectrometry (GC/MS/MS). Electron impact (EI)/MS/MS and chemical ionization (CI)/MS/MS were developed for 80 compounds, including organochlorine, organophosphorus, organonitrogen, and pyrethroids, providing unambiguous spectral confirmation for these complex matrixes. Residues were extracted from samples with acetone followed by a mixture of dichloromethane–petroleum ether. Two injections per sample were required for analysis of the entire pesticide list by EI/MS/MS and CI/MS/MS.Initial steps involving cleanup and concentration of extracts were eliminated. The excellent selectivity and good linearity allowed quantification and identification of low levels of pesticides in the most difficult matrixes. The method has been used for routine analysis of many vegetables.

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