A new facile, rapid, inexpensive, and sensitive method for the analysis of six trace trichlorophenols in seawater samples was developed by magnetic micro-solid-phase extraction coupled to liquid chromatography with tandem mass spectrometry. Core-shell covalently functionalized ferroferric oxide coated with aminated silicon dioxide and decorated with multiwalled carbon nanotubes was applied as an adsorbent to perform the extraction process. The effect of factors including solution pH, contact time, adsorbent amount, and ionic strength were investigated in detail. The obtained results revealed that the proposed adsorbent was a highly effective and low-cost magnetic micro-solid-phase extraction material for the enrichment of 2,3,4-trichlorophenol, 2,3,5-trichlorophenol, 2,3,6-trichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, and 3,4,5-trichlorophenol from seawater. Under the optimized conditions, the recoveries ranged from 88.0 to 99.5% at the three spiking levels, the limits of detection and the limits of quantification were 0.002 and 0.007 μg/L for the six trichlorophenols, respectively. The intra- and interday relative standard deviations were 2.0-6.7 and 4.5-8.9%, respectively. The calibration curves showed a good linearity in the range of 0.02-5.0 μg/L. The routine run analyses showed that the developed method was fast, simple, accurate, solvent-saving and high resolution, and it was suitable for the determination of trace trichlorophenols in seawater.
OBJECTIVE To establish a rapid and accurate method for the determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in the air by ultra-fast liquid chromatography-tandem mass spectrometry(UFLC-MS/MS). METHODS The air sample was concentrated and derivatived by 3-methyl-2(3 H)-benzothiazolonhydrazone(MBTH), and the effect of derivative conditions including the concentration of MBTH, the pH, the derivative time and temperature was investigated. The stability of derivatives, the cracking mechanism of mass spectrometry, the matrix effect of the method and air sampling efficiency were studied. The chromatographic separation was carried out on a Shim-pack XR-ODS II column(100 mm×2. 0 mm, 2. 2 μm) by using water/methanol solution as the mobile phase with the gradient elution. Detection was performed in positive multi-reaction monitoring(MRM) mode for quantification by using external standard method. RESULTS The four analytes showed good linear relationship within the range of 1. 00-100 μg/L(calculated by aldehyde) with a correlation coefficient r≥0. 9990. The limits of quantitation(LOQs) of the method(concentrated with 10 L air) were 0. 5 μg/m~3 in air, for acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde. The recoveries of the method were 90. 6%-97. 8% at the three spiked levels, and the relative standard deviations(RSDs) were between 1. 9%-6. 4%(n=6), the average sampling efficiency was between 91. 0%-97. 1%. CONCLUSION The developed method is simple, less interference and specificity, and is suitable for the simultaneous rapid determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in air of work place.
Correction for ‘In situ controllable synthesis of graphene oxide-based ternary magnetic molecularly imprinted polymer hybrid for efficient enrichment and detection of eight microcystins’ by Sheng-Dong Pan et al., J. Mater. Chem. A, 2015, 3, 23042–23052.
A sensitive method has been developed and validated for the simultaneous determination of triptolide, tripdiolide, and tripterine in human serum using hydrocortisone as an internal standard (IS). After triptolide, tripdiolide, and tripterine in human serum were extracted with ethyl acetate, the extracts were separated on an XDB C18 column (30 mm × 2.1-mm i.d., 3 µm) using a mobile phase of acetic acid/ammonium acetate (5 mmol/L, pH 4.5)/acetonitrile/methanol in gradient elution. Detection was performed by high-performance liquid chromatography coupled with atmospheric-pressure chemical ionization ion trap mass spectrometry in negative multiple reaction monitoring mode. The transition ions m/z 359 → 340, m/z 375 → 357, m/z 449 → 405, and m/z 419 → 329 were selected for the quantification of triptolide, tripdiolide, tripterine, and IS, respectively. The linear range was 1.0–100.0 ng/mL, the absolute recoveries were between 78.3 and 89.2%, the relative recoveries were between 88.1 and 94.6%, and the limits of quantification in human serum were 0.5–1.0 ng/mL for the three target compounds. The intra- and interday relative standard deviations were less than 11.9% and 13.0%, respectively. This method was found to effectively and simultaneously determine trace triptolide, tripdiolide, and tripterine in human serum and can be suitable for clinical and toxicological studies.
A reliable, accurate, and sensitive method based on a simple extraction with trichloroacetic acid at 5% and a clean-up step by means of a Strata-X SPE cartridge prior to the analysis of 14 biogenic amines and metabolites by UFLC-MS/MS was developed.
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