Chromatography-atmospheric Pressure Photoionization-tandem Mass Research Articles

Determination of Polybrominated Diphenyl Ether Flame Retardants in Surface Water by Liquid Chromatography–Atmospheric Pressure Photoionization Tandem Mass Spectrometry

ABSTRACTThis study investigated the use of liquid chromatography–atmospheric pressure photoionization tandem mass spectrometry (LC-APPI-MS/MS) for the determination of six polybrominated diphenyl ethers (PBDEs) coded as brominated diphenyl ether (BDE) 28, 47, 99, 100, 153, and 154 that are used as flame retardants. It was shown that diphenyl ethers with four to six bromine atoms can be ionized in negative polarity with parent ions corresponding to [M-Br +O]−. On the contrary, the ionization of the diphenyl ether with three bromine atoms (BDE 28), required the use of positive polarity in order to generate precursor ions [M]+. PBDEs were separated by a C18 column (50 × 4.6 mm, 1.8 µm) with a mixture of methanol–water as the mobile phase following gradient elution. Instrumental limits of detection ranged from 41 to 119 pg on the column. The method was applied to surface water samples after liquid–liquid extraction with dichloromethane. Method limits of quantification ranged from 4.1 to 73 ng L−1 and recoveries ranged from 80.5 to 95%. The estimated analytical figures were appropriate for trace determination of PBDEs. PBDEs were found to be ionized with a similar mechanism as polychlorinated biphenyls and polychlorinated naphthalenes during LC-APPI-MS/MS analysis, indicating that this technique may be suitable for other polyhalogenated polyaromatic compounds present at trace levels in the environment.

A liquid chromatography-atmospheric pressure photoionization tandem mass spectrometric (LC-APPI-MS/MS) method for the determination of triterpenoids in medicinal plant extracts.

An analytical method using liquid chromatography-atmospheric pressure photoionization tandem mass spectrometry with toluene as a dopant was developed for the determination of triterpenes in medicinal plant extracts. The 12 compounds determined have been shown to exhibit biological activity, such as gastroprotective, hepatoprotective, anti-inflammatory, antiviral and anti-tumor effects. The parameters of the atmospheric pressure photoionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection and quantification ranged from 0.4 to 157.9 µg l-1 and 1.3 to 526.4 µg l-1 , respectively. The method was validated and applied to extracts of five medicinal plants species (Mansoa alliacea (Lam.) A.H.Gentry, Bauhinia variegata var variegata, Bauhinia variegata var alboflava, Cecropia obtuse Trécul and Cecropia palmate Willd) from the Amazonian region. The concentrations of the six triterpenes quantified in the samples ranged from 0.424 mg kg-1 for ursolic acid to 371.96 mg kg-1 for β-amyrin, which were quantified by using the standard addition method (n = 3). Copyright © 2016 John Wiley & Sons, Ltd.

One-step solvent extraction followed by liquid chromatography-atmospheric pressure photoionization tandem mass spectrometry for the determination of polycyclic aromatic hydrocarbons in edible oils.

A method for rapid analysis of 16 polycyclic aromatic hydrocarbons (PAHs) in edible oils has been developed on the basis of a simplified solvent extraction and liquid chromatography-atmospheric pressure photoionization tandem mass spectrometry performed in multiple reaction monitoring mode. The briefness of the experimental procedure, the use of milliliters of acetonitrile for extraction without any further cleanup process, the short analysis time, and the excellent sensitivity and selectivity demonstrated the advantages of this practical and environmentally friendly method. All the analytes exhibited satisfactory recoveries at three spiking levels (the recoveries ranged from 77.8 to 106.4%), and the relative standard deviations were lower than 10%. The limits of quantitation of this method for the 16 PAHs were in the range of 0.02-0.43 μg/kg. The validated method was successfully applied for the determination of PAHs in coconut oil reference material (BCR-458) and real edible oil samples. The results suggested that a large-scale investigation of the concentration of PAHs in vegetable oils in China is required.

A liquid chromatography–atmospheric pressure photoionization tandem mass spectrometric method for the determination of azaarenes in atmospheric particulate matter

The development, optimization and validation of a liquid chromatography–atmospheric pressure photoionization tandem mass spectrometric (LC–APPI/MS/MS) method for the determination of 15 azaarenes (4-azafluorene, benzo[h] and -[f]quinoline, phenanthridine, acridine, 1-azafluoranthene, 4-azapyrene, benz[a]- and -[c]acridine, -10-azabenzo[a]pyrene, 7,9- and 7,10-dimethylbenz[c]acridine, dibenz[a,j]-, -[c,h] and [a,i]acridine) in airborne particulate matter is described. Each compound was detected and quantified operating in multiple reaction monitoring mode. Extraction of azaarenes was achieved using accelerated solvent extraction (ASE) with dichlormethane/methanol (50/50, v/v). After extraction, no additional clean-up procedure like solid phase or liquid/liquid extraction was necessary. Limits of quantification (S/N × 10) ranged from 0.2 pg/μl to 1.4 pg/μl, matrix dependent recoveries were between 57% and 94%, with relative standard deviations from 8% to 17%. Applicability of the method was demonstrated analyzing 10 samples of particulate matter (PM 2.5) collected in winter 2008. In all samples dimethylbenz[c]acridines as well as dibenzacridines were below the limit of quantification, concentration of the remaining analytes were in the range from 0.002 ng/m 3 to 0.356 ng/m 3.

Liquid chromatography–atmospheric pressure photoionization tandem mass spectrometry for analysis of 36 halogenated flame retardants in fish

A comprehensive, sensitive and high-throughput liquid chromatography–atmospheric pressure photoionization tandem mass spectrometry (LC–APPI-MS/MS) method has been developed for analysis of 36 halogenated flame retardants (HFRs). Under the optimized LC conditions, all of the HFRs eluted from the LC column within 14 min, while maintaining good chromatographic separation for the isomers. Introduction of the pre-heated dopant to the APPI source decreased the background noise fivefold, which enhanced sensitivity. An empirical equation was proposed to describe the relation between the ion intensity and dopant flow. The excellent on-column instrument detection limits averaged 4.7 pg, which was similar to the sensitivity offered by gas chromatography–high-resolution mass spectrometry (GC–HRMS). This method was used to analyze a series of fish samples. Good agreement was found between the results for PBDEs from LC–APPI-MS/MS and GC–HRMS.