Selective enrichment and determination of polychlorinated biphenyls in milk by solid-phase microextraction using molecularly imprinted phenolic resin fiber coating

Defective porous urchin-like ZnO/NiO microspheres-coated solid-phase microextraction fiber for analysis of trace polychlorinated biphenyls in milk

A novel fluorinated polyaniline-based solid-phase microextraction coupled with gas chromatography for quantitative determination of polychlorinated biphenyls in water samples

A method to measure dissolved polychlorinated biphenyls (PCBs) in natural waters on 30 min time frames using negligible depletion non-equilibrium solid-phase microextraction (SPME) was developed with detection limits ranging from 0.6 to 5.2 ng L−1. SPME fibres made from optical cable were inserted into a glass tube and attached to the shaft of a motor that revolved at 130 rpm to move the SPME fibres through the sampled water at a constant rate. To test for matrix interferences, measurements were made in three solutions with the same known dissolved PCB concentration but different matrices. Dissolved PCB measurements made in the presence of 8 mg L−1 of DOC and 200 mg L−1 of suspended solids were not significantly different from measurements made in deionized water, demonstrating that neither matrix interfered with SPME measurements of dissolved PCBs. PCB concentrations measured by XAD-2 resin extraction were greater than SPME measurements, suggesting that XAD measurements included DOC-associated PCBs.

Ant nest-like hierarchical porous imprinted resin-dispersive solid-phase extraction for selective extraction and determination of polychlorinated biphenyls in milk

A sample pre‐concentration device, based on solid phase microextraction (SPME) fiber and temperature programmed desorption (TPD), was developed and tested in the analysis of volatile organic compounds. The pre‐concentrator device consists of a low dead volume quartz tube that houses the SPME fiber during the extraction/ desorption steps, a Ni:Cr heating element, and a programmable power supply. Compounds are extracted from air into the SPME fiber according to their affinity and solubility to the fiber material. Following this extraction step, samples are desorbed by a pre‐programmed temperature ramp for their subsequent detection. The SPME fiber was exposed and sample extracted for a pre‐determined amount of time (1 min, in this work). Because of the limited specificity of the stationary phase in SPME fibers towards the analyte, background interfering compounds are unavoidably co‐extracted during this process. A TPD step was then applied to sequentially desorb and detect analytes and interferences. The temperature ramp was designed so as to maximize temporal resolution between target analytes and background chemical interferences. The SPME/TPD pre‐concentrator was tested with a binary chemical system consisting of dimethyl‐methylphosphate (DMMP, a chemical warfare simulant) and toluene (a common commercial solvent). Analyte desorption was monitored on‐line with a quadrupole ion trap mass spectrometer. Five SPME fibers with different stationary phases were tested: polyacrylate (PA), polydimethylsiloxane (PDMS), carboxen–polydimethylsiloxane (CAR/PDMS), polydimethylsiloxane–divinylbenzene (PDMS/DVB), and carbowax/divinylbenzene (CW/DVB). Best results were obtained with the PDMS (100 µm) fiber. Two other SPME fibers, CW/DVB and CAR/PDMS, along with the TPD step, were also successful in the temporal resolution the of DMMP and toluene. The approach is rapid in that the extraction and desorption steps take less than 3 min. Implications and applications of the SPME/TPD system as a sample pre‐concentration step in handheld devices are discussed. The simplicity of the device makes it amenable to miniaturization by available microfabrication techniques.

A method for determining polychlorinated biphenyls (PCBs) in fish roe by gas chromatography (GC) has been developed. The suitability (validation) of the process for the determination of 14 PCBs (PCB 18, PCB 31, PCB 28, PCB 52, PCB 44, PCB 101, PCB 149, PCB 118, PCB 153, PCB 138, PCB 180, PCB 170, PCB 194, PCB 209) in fish roe by GC using an electron capture detector (ECD) was evaluated according to the following criteria: selectivity, linearity, limits of detection (LOD), limits of quantification (LOQ), accuracy and precision. Automated Soxhlet extraction and sample clean-up by solid phase extraction (SPE) were proposed for extracting PCBs from fish roe. The results of the method selectivity study showed that the determination of PCBs in fish roe is not affected by other components in the sample. The correlation coefficients for fourteen PCBs ranged from 0.9962 to 0.9999 (R2 ≥0.995). The limits of detection (LOD) and limits of quantification (LOQ) of PCBs are below the maximum permissible levels set by the European Union (EU). The recovery percentage ranged from 81.5% to 107%, indicating the PCB extraction procedure's acceptability (R, 80 – 120%). The relative standard deviation (RSD, %) of the measurement results under convergence conditions ranged from 1.02% to 9.43% (RSD ≥15%). The obtained method suitability (validation) data meets the Commission Regulation (EU) No 589/2014 criteria.

Solid-phase microextraction of polychlorinated biphenyls

Carbon fiber ionization mass spectrometry coupled with solid phase microextraction for analysis of Benzo[a]pyrene

Accelerated equilibrium sampling of hydrophobic organic chemicals in solid matrices: A proof of concept on how to reach equilibrium for PCBs within 1 day

Levels and trends of PCDD/Fs and PCBs in camel milk (Camelus bactrianus and Camelus dromedarius) from Kazakhstan

Trace element determination and speciation at the part-per-trillion level (ng L−1) are challenging for most elemental detectors and become harder when complex samples are analyzed. Solid phase microextraction (SPME) can provide matrix separation along with analyte preconcentration which are essential steps to obtain interference free and measurable signals for quantitation of inorganics at these low levels. Fiber SPME was introduced first and it is still an indispensable tool for Hg and Sn speciation, and for the analysis of volatile organometallic metabolites. In recent years, several other SPME approaches have been employed for inorganic analysis, including in-tube SPME, capillary microextraction, hollow fiber SPME, micropipette tip SPME, SPME on a stir bar, SPME on a microfluidic device and dispersive SPME. A significant advancement in coatings has closely followed the developments of novel SPME formats: at this time a number of nanocomposites and polymers were available enabling the microextraction of most transition metal ions, directly in solution, without the need for derivatization.

Rapid screening of polychlorinated biphenyls in sediments using non-equilibrium solid-phase microextraction and fast gas chromatography with electron-capture detection

The subject of this study is polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) – super ecotoxicants and widely distributed organic pollutants in natural waters. Their danger lies in acute toxicity, cumulative action, and long-term effects on living organisms. The degree of water ecosystem pollution is assessed based on the levels of indicator compounds, with 16 PAHs and 7 PCBs. Assessing the levels of these super ecotoxicants when they are simultaneously present in natural waters is an urgent task of ecological monitoring in order to obtain reliable information about the pollution level of the water body. The aim of this study is to evaluate the possibility of dispersive liquid-liquid microextraction (DLLME) of PCBs and PAHs and GC-MS determination in natural waters in their simultaneous presence. To achieve the set goal, the peculiarities of simultaneous extraction and determination of PAHs and PCBs from natural waters were studied. The selected range of analyte concentrations was determined based on literature data on environmental monitoring and the maximum allowable concentrations (MAC) of the investigated components in natural waters. The similarity of the applied methods for extraction and detection of PAHs and PCBs allowed for the justification of the approach to selecting a universal sample preparation scheme for simultaneous extraction and GC-MS determination of both classes of analytes. The possibilities of modifications of DLLME extraction of PAHs and PCBs, differing in dispersion method and nature of the extractor, were studied in combination with chromatographic-mass spectrometric determination of the analytes. Simultaneous extraction of super-toxicants was achieved by applying DLLME with a binary dispersant – 500 μl acetone + 500 μl acetonitrile and 150 μl chloroform as the extractor. The chloroform extract after DLLME extraction of the analytes without re-dissolution was used for GC-MS determination of 16 PAHs and 7 PCBs on a specific 60 m long capillary column with a 5% polyarylene + 95% dimethylpolysiloxane stationary phase with gradual heating of the thermostat from 60 to 290°C. Using the selected ion monitoring (SIM) mode increased the reliability of component identification in matrices of natural waters. The possibility of mutual influence of ecotoxicants on their extraction in the presence of each other was studied. Dispersive liquid-liquid microextraction with a binary dispersant provided simultaneous extraction of analytes at a level of 80-97%. The proposed analysis scheme allowed for GC-MS determination of 16 PAHs and 7 PCBs in the presence of each other in natural waters over a wide range of concentrations (0.02-40 μg/L) with an accuracy of 7-18% (PAHs) and 11-18% (PCBs). The relative standard deviations of repeatability and reproducibility for PAHs were in the ranges of 3.1-6.5% and 4.3-7.7%, respectively, and for PCBs 2.8-5.3% and 3.4-6.0%.

Since 1980, 2145 samples of raw milk from producers in the district of Freiburg have been analysed for polychlorinated biphenyls (PCB) during a monitoring programme. In 1983, we started to search for the source of PCB, whenever milk was contaminated above the average value (above 0.2 mg/kg fat, calculated as Clophen A60). In 7 cases, previous coats of paint in the silos proved to be the cause of the PCB contamination. Five samples of milk and 4 corresponding silages as well as 1 sample of wood (from a cowshed) were investigated for all of the individual PCB components included in the technical mixtures of Clophen A30 and A60. Two samples of silages contained both low and high chlorinated biphenyls, whereas low chlorinated biphenyls (di-, tri-, and tetrachlorinated biphenyls) were not detected in the corresponding milk samples. Pentachlorinated biphenyls were only detected in the range of 1%-2%. In the samples of wood and corresponding milk, a different PCB pattern appeared. There were remarkably high percentages of hepta- and octachlorinated biphenyls as well as a lower percentage of hexachlorinated biphenyls. The exact PCB content of the milk, determined by the addition of all single components, proved to be approximately half the value obtained by the usual calculation based on the evaluation of the three main peaks of the technical PCB mixture (Clophen A60). During 1984-1987, 607 samples of raw milk were analysed for six single PCB components, for which legal tolerance levels became valid in 1988.(ABSTRACT TRUNCATED AT 250 WORDS)

A passive sampler based on solid phase microextraction (SPME) for sediment-associated organic pollutants: Comparing freely-dissolved concentration with bioaccumulation