Fast determination of phenols in contaminated soils

A poly(o-phenylenediamine) coated aluminum garter spring micro-solid phase extractor for pyrethroids in chili

An aluminum garter spring coated with poly(o-phenylenediamine) (PoPD) was developed as a sorbent for the micro-solid phase extraction of seven pyrethroids, bifenthrin, fenpropathrin, lambda-cyhalothrin, cyfluthrin, permethrin, cypermethrin and deltamethrin from fresh chili, chili flakes, and curry pastes. The extraction was qualified and quantified by a gas chromatograph coupled with an electron capture detector. Under optimum conditions, the linearity was at a concentration range of 10-3000 µg kg-1. The limits of detection and limits of quantitation of 9.3 to 34.2 μg kg-1, and 11.8 to 48.6 μg kg-1, respectively, were obtained with good sorbent-to-sorbent reproducibility, and outstanding reusability. When applied to determine the seven pyrethroids in chili samples, some pyrethroids were detected up to 30.3 ± 1.2 μg kg-1. This proposed method is simple, with potential applications in the trace analysis of other compounds.

Optimization of headspace solid-phase microextraction of volatile organic compounds from dry soil samples by porous coatings using COMSOL Multiphysics

Headspace solid-phase microextraction (HSSPME) is one of the simplest and cost-efficient sample preparation approaches for determination of volatile organic compounds (VOCs) in soil. This study was aimed at the development of the model for numerical optimization of HSSPME of volatile organic compounds from dry soil samples by porous coatings using COMSOL Multiphysics (CMP). ‘Transport of Diluted Species in Porous Medium’ physics was used for modeling. Effect of sample mass, pressure, fiber-headspace and soil-headspace distribution constants on extraction profiles and time of 95% equilibrium has been studied using the developed model. Equilibrium extraction under atmospheric pressure (1 atm) can take up to 97 min, while under vacuum (0.0313 atm) – 2.3 min. Equilibration time under vacuum was 42-43 times lower than under 1 atm at all studied distribution constants and sample masses. The developed model was modified for optimization of pre-incubation time using ‘Transport of Diluted Species’ physics. According to the obtained plots, 95% equilibration time can reach 13.3 min and depends on both sample mass and soil-headspace distribution constant of the analyte. The developed model can be recommended for optimization of pressure, preincubation and extraction time when fiber-headspace and soil-headspace distribution constants, soil porosity and density are known.

Simultaneous detection of eight phenols in food contact materials after electrochemical assistance solid-phase microextraction based on amino functionalized carbon nanotube/polypyrrole composite

An electrochemical assistance solid-phase microextraction (EA-SPME) was developed based on amino functionalized multi-walled carbon nanotube/polypyrrole (MWCNTs-NH₂/PPy) composite coating. It was applied for the extraction of eight phenols in food contact material, including 2-chlorophenol, o-cresol, m-cresol, 2,4-dichlorophenol, 4-tert-butylphenol, 4-chlorophenol, 4-tertoctylphenol and alpha-naphthol. MWCNTs-NH₂/PPy coating was characterized by scanning electron microscopy, transmission electron microscope, X-ray energy spectrometer, X-ray diffraction, Fourier transform infrared and thermogravimetric analysis. The adsorption mechanism of phenols on the composite coatings was investigated. The coating modified steel-wire as an extraction fiber has good electroconductibility, reproducibility and long service life. A determination method for the eight phenols was established by EA-SPME coupled with gas chromatography-flame ionization detection. Under the optimal experimental conditions (extraction temperature: 40 °C; extraction time: 30 min; stirring rate: 600 rpm; NaCl concentration: 0.15 g mL^-1; desorption temperature: 250 °C and desorption time: 4 min), the detection linear range was 0.005-50 μg L^-1 (R²>0.99), and the detection limit was 0.001-0.1 μg L^-1 (S/N = 3). For the quintuple analysis of 50 μg L^-1 phenols, the single fiber RSDs were 2.2-12.4%, and the fiber-to-fiber RSDs were 1.9-10.5%. The method was used to detect the migration quantity of the eight phenols from five canned packaging materials, which showed satisfactory recovery 87.3-118.9%.

Quantitative detection of phenol in wastewater using square wave voltammetry with pre-concentration

Phenol is a common pollutant found in wastewater, and its allowable discharge limit is 0.5 parts-per-million (ppm). Therefore, it is critical to monitor phenol in the sub-ppm range with high sensitivity and a low limit of detection. Herein, we report a quantitative method for detecting phenol in industrial wastewater through square wave voltammetry (SWV), in which phenol is oxidized to phenoxyl radicals and then became catechol and hydroquinone for detection. By using this method, phenol in the sub-ppm range can be detected reliably over a wide pH range. The sensitivity can be further improved by using a pre-concentration step for phenol before scanning. The method has a limit of detection of 0.1 ppb for phenol. Finally, three graphite electrodes were applied as working, counter and reference electrodes, respectively, in a millifluidic device for continuous detection of phenol in industrial wastewater flowing at 300 μL/min. Because of its simplicity, the sensor can be mass-produced and deployed on a large scale to monitor phenol in industrial wastewater.

Differentiation of isomeric cresols by silylation in combination with gas chromatography/mass spectrometry analysis

RATIONALE

m-Cresol is listed as a priority controlled contaminant in many countries, but it is very difficult to accurately determine isomeric cresols due to their incomplete chromatographic separation on commercially available chromatographic columns and their nearly identical mass spectra.

METHODS

Silylation of isomeric cresols was carried out by treatment with N-methyl-N-(trimethylsilyl)trifluoroacetamide. The formed trimethyl(tolyloxy)silanes were analyzed by gas chromatography/mass spectrometry (GC/MS). Theoretical calculations were carried out with the Gaussian 03 program using the density functional theory (DFT) method at the B3LYP/6-311 + G(2d,p) level.

RESULTS

The derivatives of three isomeric cresols and six isomeric xylenols have been completely separated on an HP-5MS capillary column within a GC run of only 10 minutes. In addition, the derivative o-cresol can be very easily differentiated from its isomers due to its characteristic base peak ion at m/z 91 in electron ionization (EI)-MS. DFT calculation results indicated that the formation of the abundant fragment ion at m/z 91 is attributed to a facile dissociation pathway involving the shift of a neighboring phenylmethyl hydrogen atom in EI-MS of trimethyl(o-tolyloxy)silane.

CONCLUSIONS

Silylation provides a promising solution for simultaneous determination of isomeric cresols and isomeric xylenols.

A nanosized magnetic metal-organic framework of type MIL-53(Fe) as an efficient sorbent for coextraction of phenols and anilines prior to their quantitation by HPLC

The authors describe the synthesis of a magnetic metal-organic framework (MOF) of type MIL-53(Fe) for coextraction of phenols and anilines from various environmental samples. A quick method for dispersive micro-solid phase extraction (D-μ-SPE) was developed for coextraction of the analytes 4-nitrophenol (4-NP), 4-chlorophenol (4-CP), 4-chloroaniline (4-CA), 1-amino-2-naphtol (1-A2N) and 2, 4-dichloroaniline (2, 4-DCA). The MOF was characterized by SEM, TEM, FT-IR, EDS, thermogravimetry, VSM and XRD. The method was optimized by response surface methodology combined with desirability function approach, specifically with respect to pH value of the sample, amount of sorbent, sorption time, salt concentration, sample volume, type and volume of the eluent, and elution time. Following elution with acetonitrile, the analytes were quantified by HPLC with photodiode array detection. Responses are linear in 0.1-2000 μg·L^-1 concentration ranges. The limits of detection and relative standard deviations (for n = 5) are in the range of 0.03-0.2 μg·L^-1 and 3.5-12.6%, respectively. Enrichment factors are 113, 61, 87, 144 and 114 for 4-NP, 4-CP, 4-CA, 1-A2N and 2,4-DCA, respectively. Recoveries from spiked samples ranged from 39.5 to 93.3%. The magnetic sorbent was successfully applied to the coextraction and determination of the analytes in river, rain and hookah water samples. Graphical abstract Schematic presentation for the synthesis of (a) Fe₃O₄ nanoparticles (NPs) and (b) Fe₃O₄@MIL-53(Fe). Fe₃O₄@MIL-53(Fe) was employed as a new nanosorbent in dispersive micro-solid phase extraction of phenols and anilines. The limits of detection are in the range of 0.03-0.2 μg·L^-1.

Extraction of phenolic compounds from water samples by dispersive micro-solid-phase extraction

In this article, the use of magnetically separable sorbent polyaniline/silica-coated nickel nanoparticles is evaluated under a dispersive micro-solid-phase extraction approach for the extraction of phenolic compounds from water samples. The sorbent was prepared by in situ chemical polymerization of aniline on the surface of silica-modified nickel nanoparticles and was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectrometry, and vibrating sample magnetometry. Effective variables such as amount of sorbent (milligrams), pH and ionic strength of sample solution, volume of eluent solvent (microliters), vortex, and ultrasonic times (minutes) were investigated by fractional factorial design. The significant variables optimized by a Box-Behnken design were combined by a desirability function. Under the optimized conditions, the calibration graphs of analytes were linear in a concentration range of 0.02-100 μg/mL, and with correlation coefficients more than 0.999. The limits of detection and quantification were in the ranges of 10-23 and 33-77 μg/L, respectively. This procedure was successfully employed in the determination of target analytes in spiked water samples; the relative mean recoveries ranged from 96 to 105%.

Oxidized multiwalled carbon nanotubes as a novel solid-phase microextraction fiber for determination of phenols in aqueous samples

A simple and environmentally friendly method for determination of seven phenols using solid-phase microextraction (SPME) coupled to high-performance liquid chromatography (HPLC) has been developed. Several materials were used as stationary phase of SPME fibers and an oxidized multiwalled carbon nanotubes material was found to be effective in carrying out simultaneous extraction of phenols in aqueous samples. Compared with the widely used commercially available SPME fibers, this proposed fiber had much lower cost, longer lifetime (over 150 times), shorter analysis time (30 min of extraction and 3 min of desorption time) and comparable or superior extraction efficiency for the investigated analytes. The extraction and desorption conditions were evaluated and the calibration curves of seven phenols were linear (R(2)> or =0.9908) in the range from 10.2 to 1585 ng mL(-1). The limits of detection at a signal-to-noise (S/N) ratio of 3 were 0.25-3.67 ng mL(-1), and the limits of quantification calculated at S/N=10 were 0.83-12.25 ng mL(-1) for these compounds. The possibility of applying the proposed method to environmental water samples analysis was validated.

Determination of valproic acid in human serum and pharmaceutical preparations by headspace liquid-phase microextraction gas chromatography-flame ionization detection without prior derivatization

An efficient and fast extraction technique for the enrichment of valproic acid from human blood serum samples using the headspace liquid phase microextraction (HS-LPME) combined with gas chromatography (GC) analysis has been developed. The extraction was conducted by suspending a 2 microL drop of organic solvent in a 1 mL serum sample; following 20 min of extraction, withdrawing organic solvent into a syringe and injection into a GC with a flame ionization detector (FID), without any further pre-treatment. Four organic solvents, 1-decanole, benzyl alcohol, 1-octanol and n-dodecane, were studied as extractants, and n-dodecane was found to be the most sensitive solvent for valproic acid. The results revealed that HS-LPME is suitable for the successful extraction of valproic acid from human blood serum samples. Parameters like extraction time, ionic strength, pH, organic solvent volume, and temperature of the sample were studied and optimized to obtain the best extraction results. An enrichment factor of 27-fold was achieved in 20 min. The procedure resulted in a relative standard deviation of <13.2% (n=7) and a linear calibration range from 2 to 20 microg mL(-1) (r>0.98), and the limit of detection was 0.8 microg mL(-1) in serum blank samples. Overall, LPME proved to be a fast, sensitive and simple tool for the preconcentration of valproic acid from real samples. The proposed method was also applied to the analysis of valproate in pharmaceutical preparations.

Characterization of an urban landfill soil by using physicochemical analysis and solid phase microextraction (SPME)-GC/MS

We have aimed at characterizing top soil samples taken in-situ from five different locations of the unregulated dumping site in Eskişehir/Turkey for a period of six months. The study is the first attempt in the city and in Turkey, regarding particularly the SPME (Solid Phase Microextraction Technique) analysis method utilized. A comprehensive research has been conducted to produce critical soil data to be used for indicating current risks as well as the urgency of rehabilitating the site and establishing a sanitary landfill in the site. Conventional physicochemical analytical methods and SPME technique were used to analyze the samples. Physicochemical analyses were performed for determining the pH, total dried matter, volatile matter, total nitrogen, phosphorus, macro elements and heavy metals. Meteorological data were also recorded for the same period. SPSS.10.0 statistical program was used to determine the correlation between meteorological data and physicochemical analysis results. Mean values were used in the correlation analyses. These data indicated that the air temperature and precipitation have significant effects on soil characteristics. SPME, coupled with GC/MS, was used to identify eighty six volatile and semi-volatile organic compounds contained in soil samples. The samples were extracted by headspace SPME with heating (DeltaHS-SPME). SPME analyses were conducted using a commercially available polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber having a film thickness of 65 microm (Supelco) as a capture medium. The experimentally optimized headspace sampling conditions were arranged (15 min. at 50 degrees C) before a 30 min. sampling period.

Optimization of an analytical methodology for the determination of alkyl- and methoxy-phenolic compounds by HS-SPME in biomass smoke

A sampling and analysis method for the determination of 21 phenolic compounds in smoke samples from biomass combustion has been developed. The smoke is used to make smoked foods, following an artisanal procedure used in some parts of the Canary Islands. The sampling system consists of a Bravo H air sampler, two impingers, each one containing an aqueous solution of sodium hydroxide 0.1 mol L(-1), followed by a silica gel trap. The variables optimized to reach the best sampling conditions were volume of absorbent solution and sampling flow. Under the optimum conditions, 100 mL of absorbent solution of NaOH 0.10 mol L(-1) and 2 L min(-1) for the sampling flow, sampling efficiencies are higher than 80%. Analysis of phenolic compounds was carried out by headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). Five different fiber coatings were employed in this study. By means of a central composite design, extraction time, salt concentration, and pH of the solution were optimized: 65-microm carbowax-divinylbenzene, extraction time 90 min, concentration in NaCl of 35% (m/v), and pH 2 yielded the highest response. Detection limits of phenol and their alkyl derivatives, guaiacol and eugenol, are between 1.13 and 4.60 ng mL(-1). 3-Methoxyphenol, 2,6-dimethoxyphenol, and vanillin have detection limits considerably higher. Good linearity (R2 > or = 0.98) was observed for all calibration curves in the established ranges. The reproducibility of the method (RSD, relative standard deviation) was found to oscillate between 7 and 18% (generally close or lower than 10%).

Automated dynamic headspace organic solvent film microextraction for benzene, toluene, ethylbenzene and xylene

A simple, fast and efficient dynamic headspace-organic solvent film microextraction (DHS-OSFME) method using a new automatic device was developed. The renewable organic films were formed inside a microsyringe barrel using the uniform and repeated movement of the syringe plunger enabled by programmable stirring motor. The plunger speed, number of extraction cycles, and dwell time (stop time after each half round) were controlled by a computer software, which was written by C++ Builder. A theoretical treatment of the DHS-OSFME based on the consecutive first-order process is proposed in this report. A mathematical solution for the dynamic process of the mass transfer was obtained by correlating the variation of analyte concentration in the syringe volume with the plunger speed and the amount of analyte extracted to the OSF. Benzene, toluene, ethylbenzene, and o-xylene (BTEX) were employed as model compounds to assess the extraction procedure and were determined by gas chromatography-flame ionization detection. Of the three organic solvents (1-octanol, benzyl alcohol and n-dodecane) studied as extractants, n-dodecane proved to be the most sensitive solvent for the extraction of these analytes. Several parameters, including the syringe withdrawal rate, dwelling time, number of extraction cycles, sampling volume, sample temperature, and ionic strength of the solution, were investigated for their effects on the extraction performance. The calibration graphs were linear in the range of 0.5-200 ng ml(-1), with the detection limits between 0.18 and 0.35 ng ml(-1). Wastewater samples were extracted by the optimized method, and determined using the standard addition method.

Solid-phase microextraction for qualitative and quantitative determination of migrated degradation products of antioxidants in an organic aqueous solution

Low molecular weight aromatic substances may migrate out from plastic packaging to their contents, especially if they consist of organic aqueous solutions or oils. It is, therefore, extremely important to be able to identify and quantify any migrated substances in such solutions, even at very low concentrations. We have in this work investigated and evaluated the use of solid-phase microextraction for the specific task of extraction from an organic aqueous solution such as a simulated pharmaceutical solution consisting of 10 vol.% ethanol in water. The goal was furthermore to investigate the possibility of simultaneously identifying and quantifying the substances in spite of differences in their chemical structures. Methods were developed and evaluated for extraction both with direct sampling and with headspace sampling. Difficulties appeared due to the ethanol in the solution and the minute amounts of substances present. We have shown that a simultaneous quantification of migrated low molecular weight degradation products of antioxidants using only one fibre is possible if the extraction method and temperature are adjusted in relation to the concentration levels of the analytes. Comparions were made with solid-phase extraction.

Determination of phenols in lake and ground water samples by stir bar sorptive extraction–thermal desorption–gas chromatography–mass spectrometry

A simple and inexpensive method for sorptive extraction of phenols from water samples is presented. A polydimethyl siloxane (PDMS) stir bar (Twister) is used as an extraction medium for derivatized phenols, which is thermally desorbed and analyzed by gas chromatography-mass spectrometry (GC-MS). Its performance was illustrated and evaluated for the enrichment of microg l(-1) to ng l(-1) of phenol and selected chlorophenols in water samples. The method showed good linearity, recoveries and blank levels, as well as advantages such as sensitivity, simplicity, low cost and high feasibility, being successfully applied for the analysis of phenolic compounds in natural water samples.

Modeling of chlorophenols competitive adsorption on soils by means of the ideal adsorbed solution theory

The adsorption of 3-chlorophenol (3-CP) and 3,5-dichlorophenol (3,5-CP) on two Italian soils was studied at 20 degrees C. Experiments on the pure components showed that 3,5-CP was more strongly adsorbed than 3-CP, and that the adsorption capacity could be related to the organic carbon fraction of the soil. Competitive adsorption data were described by the fully predictive ideal adsorbed solution (IAS) theory. To this end, the Langmuir parameters determined from pure component adsorption data were used. Results showed that at low 3,5-CP concentration (up to 5-10 mM) the model describes satisfactorily the binary system behavior, whereas at higher concentrations predictions fail, suggesting that non ideality effects in the adsorbed phase should be accounted for.

Dodecylsulfate-doped polypyrrole film prepared by electrochemical fiber coating technique for headspace solid-phase microextraction of polycyclic aromatic hydrocarbons

The electrochemical fiber coating (EFC) technique was used for the preparation of dodecylsulfate-doped polypyrrole (PPy-DS), and applied as a new fiber for solid-phase microextraction (SPME) procedures. PPy-DS film was directly electrodeposited on the surface of a platinum wire from an aqueous solution containing pyrrole and sodium dodecylsulfate, using cyclic voltammetry (CV). The effect of polymerization conditions and type of dopants on the thermal stability, adhesion and extraction characteristics of the fiber were investigated. The electron microscopy imaging of PPy-DS film suggested that the surface fiber coating was well-distributed with a porous structure. The fiber coating can be prepared easily in a reproducible manner, and it is inexpensive and has a stable performance at high temperatures (up to the 300 degrees C). The extraction properties of the fiber to eight polycyclic aromatic hydrocarbons (PAHs) were examined, using a headspace-SPME (HS-SPME) device coupled with gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The results revealed study shows that PPy-DS as a SPME fiber coating is suitable for the successful extraction of PAHs. The effects of the extraction parameters including exposure time, sampling temperature, salt concentration, and stirring rate on the extraction efficiency have been studied. A satisfactory reproducibility for extractions from spiked water samples at PPb-level with R.S.D. < 7.6% (n = 7) was obtained. The calibration graphs were linear in the range of 0.5-100ng ml(-1) and detection limits for the selected PAHs were between 0.05-0.16 ng ml(-1). Comparing the HS-SPME results for extraction and determination of PAHs using PPy-DS fiber with the corresponding literature data using PDMS fiber shows that the proposed fiber has a better detection limit for low molecular weight PAHs. The life span and stability of PPy-DS fiber is good and it can be used more than 50 times at 250 degrees C without any significant change in sorption properties.

Determination of pesticides in soil by liquid-phase microextraction and gas chromatography–mass spectrometry

Trace amounts of pesticides in soil were determined by liquid-phase microextraction (LPME) coupled to gas chromatography-mass spectrometry (GC-MS). The technique involved the use of a small amount (3 microl) of organic solvent impregnated in a hollow fiber membrane, which was attached to the needle of a conventional GC syringe. The organic solvent was repeatedly discharged into and withdrawn from the porous polypropylene hollow fiber by a syringe pump, with the pesticides being extracted from a 4 ml aqueous soil sample into the organic solvent within the hollow fiber. Aspects of the developed procedure such as organic solvent selection, extraction time, movement pattern of plunger, concentrations of humic acid and salt, and the proportion of organic solvent in the soil sample, were optimized. Limits of detection (LOD) were between 0.05 and 0.1 microg/g with GC-MS analysis under selected-ion monitoring (SIM). Also, this method provided good precision ranging from 6 to 13%; the relative standard deviations were lower than 10% for most target pesticides (at spiked levels of 0.5 microg/g in aqueous soil sample). Finally, the results were compared to those achieved using solid-phase microextraction (SPME). The results demonstrated that LPME was a fast (within 4 min) and accurate method to determine trace amounts of pesticides in soil.

Novel benzo-15-crown-5 sol-gel coating for solid-phase microextraction

A novel dihydroxy-terminated benzo-15-crown-5 was synthesized and applied to prepare a solid-phase microextraction (SPME) fiber coating with sol-gel technology. The optimization of the sol-gel process was studied. The coating method with sol-gel was improved and completed in one run, which economized materials and allowed easier control of the fiber thickness. The repeatability of coating fiber to fiber was better than 4.94% (RSD). The surface of the fiber coating was well-distributed and an electron microscopy experiment suggested a porous structure for crown ether coating, providing high surface areas and allowing for high extraction efficiency. The coating has a high thermal stability (350 degrees C), long lifetime and can stand solvent (organic and inorganic) rinsing due to the chemical binding between the coating and the fiber surface. Non-polar benzene, toluene, ethylbenzene, xylenes, chlorobenzenes, polar phenolic compounds and arylamines were used to evaluate the character of the fiber coating by headspace SPME-gas chromatography technology. For phenols, the linear concentrations ranged from 5 to 1000 microg/l, the detection limits were between 0.05 and 1 microg/l, and the RSD was less than 5%. The addition of benzo-crown ether not only increases the thermal stability of the fiber coating, but also enhances the selectivity of the fiber coating. Compared with commercially available SPME fibers poly(dimethylsiloxane) and polyacrylate, the few phases showed better selectivity and sensitivity towards non-polar and polar aromatic compounds.

Hydrogen peroxide lifetime as an indicator of the efficiency of 3-chlorophenol Fenton's and Fenton-like oxidation in soils

In this work the possibility of using the hydrogen peroxide lifetime as indicator of the oxidation efficiency of Fenton's and Fenton-like processes for soil treatment was explored. A reactivity scale, in terms of the oxidizing power in the different tested operating conditions (pH, iron sulfate concentration and stabilizer concentration) was built for each soil as a function of the hydrogen peroxide lifetime. Its validity was then confirmed through 3-chlorophenol Fenton's and Fenton-like slurry-phase oxidation experiments. The proposed reactivity scale proved to be effective for comparing the different operating conditions for the same soil, but failed when used to compare the oxidation performances for different soils, since the different adsorptive behavior of the tested soils may have influenced the contaminant removal rate.

Solid-phase microextraction liquid chromatography/tandem mass spectrometry for the analysis of chlorophenols in environmental samples

Liquid chromatography with atmospheric pressure chemical ionisation mass spectrometry (LC/APCI-MS), using negative ion detection in a triple quadrupole instrument, was used for the determination of chlorophenols (CPs) in environmental samples. In-source collision-induced dissociation (CID) was compared with MS/MS fragmentation. In general, less fragmentation was observed in MS/MS as compared with in-source CID, with the latter providing more intense fragment ions due to chemical ionisation. Under MS/MS conditions [M - H - HCl](-) was the main fragment ion observed for all compounds except for pentachlorophenol, which showed no fragmentation. For multiple reaction monitoring (MRM) acquisition mode, the transition from [M - H](-) to [M - H - HCl](-) was selected, leading to detection limits down to 0.3 ng injected. Direct and headspace-solid-phase microextraction (HS-SPME) were used as preconcentration procedures for the analysis of CPs in wood and in industrially contaminated soils. CPs were quantified by standard addition, which led to good reproducibility (RSD between 4 and 11%) in both SIM and MRM modes, and detection limits down to ng/g. The combination of MS/MS and in-source CID allowed confirmation of the presence of CPs in environmental samples.

Separation and identification of aromatic acids in soil and the Everglades sediment samples using solid-phase microextraction followed by capillary zone electrophoresis

The separation and identification of aromatic acids in soil and the Everglades sediment samples was carried out using solid-phase microextraction (SPME) followed by capillary zone electrophoresis (CZE). The soil and sediment samples were subject to a series of sample treatments including oxidative hydrolysis with molecular oxygen in a sodium hydroxide solution, acidification and filtration. The aromatic acids in the sample filtrate were extracted using SPME with a polyacrylate-coated fiber. The acids adsorbed on the fiber were subsequently desorbed in methanol. The desorbed acids were then separated by CZE. Several aromatic acids (e.g.. salicylic acid, p-coumaric acid, ferulic acid and vanillic acid) in both soil and sediment samples were separated, identified and quantified. The results of this study show that the combination of SPME with CZE is promising for environmental analysis.