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The gas chromatography/mass spectrometric assay method was developed for the determination of 13 non-steroidal anti-inflammatory drugs (NSAIDs) in river water. Extraction was achieved by a liquid-phase extraction procedure using methylene chloride. The extract was reacted for 30 min at 80°C based on the formation of methyl ester with 1.0 M HCl in methanol(More)
A simple high performance liquid chromatographic (HPLC) method and a highly sensitive gas chromatography mass spectrometric (GC-MS) method have been established for the determination of ortho-phthalaldehyde (OPA) in water. These methods are based on the derivatization of OPA with hydrazine in water. The following optimum reaction conditions were(More)
A gas chromatography-mass spectrometric (GC-MS) method has been established for the determination of hydrazine in drinking water and surface water. This method is based on the derivatization of hydrazine with ortho-phthalaldehyde (OPA) in water. The following optimum reaction conditions were established: reagent dosage, 40 mg mL(-1) of OPA; pH 2; reaction(More)
Electronic cigarettes (E-cigarettes) are devices that are refilled with replacement liquids, which normally contain propylene glycol, nicotine and the desired flavor blend. Many consumers suspect that hazardous substances are present in addition to nicotine content. In this study, eight contaminated compounds in 105 replacement liquids from 11 types of(More)
BACKGROUND Saliva samples are easily collectable and non-invasive, and the monitoring of natural steroidal hormones, such as estrone (E1), 17β-estradiol (E2), estriol (E3), progesterone (P), and testosterone (T), in saliva has attracted much attention due to its numerous potential clinical and health-related applications. Because E1, E2, E3, P and T are(More)
An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to determine the level of hydrazine in drinking water. The method is based on the derivatization of hydrazine with naphthalene-2,3-dicarboxaldehyde (NDA) in water. The optimum conditions for UPLC-MS/MS detection were determined as follows: derivatization(More)
A headspace solid-phase micro extraction (HS-SPME) and gas chromatography-tandem mass spectrometric (GC-MS/MS) method is described to detect hydrazine after derivatization with 1,1,1-trifluoro-2,4-pentanedione (1,1,1-TFPD) to 3-methyl-5-(trifluoromethyl) pyrazole in industrial waste water. The following optimal HS-SPME conditions were used: 85(More)
Direct injection and solid-phase extraction methods for the determination of diquat and paraquat in surface and drinking water were developed using liquid chromatography with tandem mass spectrometry. The signal intensities of analytes based on six ion-pairing reagents were compared with each other, and 12.5 mM nonafluoropentanoic acid was selected as the(More)
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