A novel microextraction approach termed ionic liquid based ultrasound-assisted emulsification microextraction (IL-USAEME) combined with high-performance liquid chromatography-ultraviolet (HPLC-UV) was developed for the preconcentration and detection of organic ultraviolet (UV) filters in environmental water samples. An ionic liquid (IL) was used in place of an organic solvent as in conventional USAEME. In the study, orthogonal array designs (OAD) were employed for the optimization of the extraction parameters: type of IL, pH of the sample, extraction volume, ultrasonic time and salt concentration. In the first step, a mixed level OAD matrix, OA _(16) (4 ~1×2 ~(12)) was employed for the initial optimization. Based on the results of the first step, an ultra-hydrophobic IL, 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate was chosen as the IL extractant and sample pH was set at a value of 3. Ultrasonic time, extraction volume and salt concentration were further optimized in the second step by an OA _(16) (4 ~5) matrix. Under the latter optimized conditions, calibration curves with coefficients of estimation higher than 0.997 over the concentration range of 5 and 1000ng/ml, and the relative standard deviations for six replicates of the extraction from 2.6 to 6.6% were obtained. The limits of detection for four organic UV filters were between 0.5 and 1ng/ml. The validated technique was applied to the analysis of organic UV filters in environmental water samples.
For the first time, a simple solvent microextraction method termed vortex-assisted liquid-liquid microextraction (VADLLME) coupled with gas chromatography-mass spectrometry (GC-MS) has been developed and used for the analysis of six benzophenone ultraviolet (UV) filters (i.e. benzhydrol, 2,4-dihydroxybenzophenone, benzophenone, 2-hydroxy-4-methoxybenzophenone, ethylhexyl salicylate and homosalate) in water samples. The most favorable extraction variables in the VADLLME process were determined. In the extraction procedure, 40 μL of tetrachloroethene as extraction solvent were directly injected into a 15-mL centrifuge tube containing 10. mL of aqueous sample, adjusted to pH 4 for VADLLME. After VADLLME, the extract was evaporated under a gentle nitrogen gas stream and then reconstituted with N,. O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA), thus allowing the target analytes to be converted into their trimethylsilyl derivatives to optimize the GC-MS analysis. No centrifugation and disperser solvent were required in this microextraction procedure. Significantly, short extraction time and high extraction efficiency were achieved. This method opens up a potentially new horizon for on-site dispersive liquid-liquid microextraction. Under the optimum conditions, the proposed method provided good enrichment factors up to 310, with relative standard deviations ranging from 6.1 to 12.9%. The limits of quantification were in the range of 20-100. ng/L, depending on the analytes. The linearities were between 0.05 and 10 μg/L and 0.1 and 10 μg/L for different UV filters. Finally, the proposed method was successfully applied to the determination of UV filters from spiked genuine water samples and acceptable recoveries over the range of 71.0-120.0% were obtained.
A method for the determination of 11 UV-filter compounds in sludge has been developed and evaluated. The procedure includes the use of non-porous polymeric membranes in combination with pressurised liquid extraction (PLE). Firstly, the solid sample, wetted with the extraction solvent, was enclosed into tailor-made bags prepared with low density polyethylene. Secondly, these packages were submitted to a conventional PLE (70 degrees C, 4 cycles of 5 min static time). Finally, the analytes were determined by liquid chromatography-atmospheric pressure photoionisation-tandem mass spectrometry. The main advantage of this procedure is the reduction of time, solvent and labour effort ought to the combination of extraction and clean-up in a single step. Although the extraction is not quantitative (thus, standard addition is recommended for quantification) selectivity is clearly gained using the membrane as a consequence of the differences of permeation and transport through the membrane between the analytes and other sample matrix components. The optimised protocol provides limits of detection ranging from 0.3 ng g(-1) (ethylhexyl dimethyl p-aminobenzoate (OD-PABA)) to 25 ng g(-1) (ethylhexyl triazone (EHT)) with only 0.5 g of sludge sample. All the studied UV filters were found in the samples at concentration levels between 1.4 and 2479 ng g(-1), emphasising the high adsorption potential of this kind of environmental pollutants onto solid samples such as sludge. Also, this method has permitted the determination of seven of the studied UV filters in sludge samples for the first time.
A simple, inexpensive sample preparation procedure. based on the matrix solid-phase dispersion (MSPD) technique, for the determination of six UV filters: 2-ethylhexyl salicylate (EHS), 3,3,5-trimethylcyclohexyl salicylate (Homosalate, HMS), 3-(4-methylbenzylidene) camphor (4-MBC), isoamyl-p-methoxycinnamate (IAMC), 2-ethylhexyl-p-methoxycinnamate (EHMC) and octocrylene (OCR), in dust from indoor environments is presented and the influence of several operational parameters on the extraction performance discussed. Under the final working conditions, sieved samples (0.5 g) were mixed with the same amount of anhydrous sodium sulphate and dispersed with 2 g of octadecyl bonded silica (C18) in a mortar with a pestle. This blend was transferred to a polypropylene solid-phase extraction cartridge containing 2 g of activated silica, as the clean-up co-sorbent. The cartridge was first rinsed with 5 mL of n-hexane and the analytes were then recovered with 4 mL of acetonitrile. This extract was adjusted to I mL, filtered and the compounds were determined by gas chromatography combined with tandem mass spectrometry (GC-MS/MS). Recoveries for samples spiked at two different concentrations ranged between 77% and 99%, and the limits of quantification (LOQs) of the method between 10 and 40 ng g(-1). Analysis of settled dust from different indoor areas. including private flats, public buildings and vehicle cabins, showed that EHMC and OCR were ubiquitous in this matrix, with maximum concentrations of 15 and 41 mu g g(-1), respectively. Both UV filters were also quantified in dust reference material SRM 2585 for first time. EHS, 4-MBC and IAMC were detected in some of the analyzed samples, although at lower concentrations than EHMC and OCR.
A new analytical method for the determination of four hydroxylated benzophenone UV filters (i.e. 2-hydroxy-4-methoxybenzophenone (HMB), 2,4-dihydroxybenzophenone (DHB), 2,2'-dihydroxy-4-methoxybenzophenone (DHMB) and 2,3,4-trihydroxybenzophenone (THB)) in sea water samples is presented. The method is based on dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC-MS) determination. The variables involved in the DLLME process were studied. Under optimized conditions, 1000μL of acetone (disperser solvent) containing 60μL of chloroform (extraction solvent) were injected into 5mL of aqueous sample adjusted to pH 4 and containing 10% NaCl. Before injecting into the GC-MS system, the DLLME extracts were evaporated under an air stream and then reconstituted with N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA), thus allowing the target analytes to be converted into their trimethylsilyl derivatives. The best conditions for the derivatization reaction were 75°C and 30min. High enrichment factors for all the target analytes (ranging from 58 to 64) and good repeatability (RSD around 6%) were obtained. The limits of detection were in the range of 32-50ngL~(-1), depending on the analyte. The recoveries obtained by using the proposed DLLME-GC-MS method evidenced the presence of matrix effects for some of the target analytes, and thereby the standard addition calibration method was employed. Finally, the validated method was applied to the analysis of sea water samples.
This paper describes the development of a multi-residue method for the determination of 36 emerging organic pollutants (26 biocides, 5 UV-filters and 5 benzothiazoles) in raw and treated wastewater, activatedsludge and surface water using liquid chromatography–tandem mass spectrometry (LC–MS/MS). The target analytes were enriched from water samples adjusted topH6 by solid-phase extraction (SPE) on Oasis HLB 200mg cartridges and eluted with a mixture of methanol and acetone (60/40, v/v). Extraction of freeze-dried sludge samples was accomplished by pressurized liquid extraction (PLE) using a mixtureof methanol and water (50/50, v/v) as extraction solvent followed by SPE. LC–tandem MS detection was compared using electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) inpositive and negative ionization mode. ESI exhibited strong ion suppression for most target analytes, while APCI was generally less susceptible to ion suppression but partially leading to ion enhancement of up to a factor of 10. In general, matrix effects could be compensated using stable isotope-labeled surrogate standards, indicated by relative recoveries ranging from 70% to 130%. In wastewater, activated sludge and surface water up to 33 analytes were detected. Maximum concentrations up to 5.1 and 3.9gL~（-1） were found in raw wastewater for the water-soluble UV-filters benzophenone-4 (BZP-4) and phenylbenzimidazole sulfonic acid (PBSA), respectively. For the first time, the anti-dandruff climbazole was detected in raw wastewater and in activated sludge with concentrations as high as 1.4gL~（-1） and 1.2g g TSS~（-1）, respectively. Activated sludge is obviously a sink for four benzothiazoles and two isothiazolones, as concentrations were detected in activated sludge between 120 ng g TSS~（-1） (2-n-octyl-4-isothiazolin-3-one, OIT) to 330 ng g TSS~（-1） (benzothiazole-2-sulfonic acid, BTSA).
Personal care products (PCPs) are widely used emerging contaminants which can cause adverse environmental effects. This paper reports the development and validation of a method based on solid-phase extraction (SPE) and ultra-high-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry (UHPLC-(ESI)MS-MS) for simultaneously determining eleven PCPs: 4 preservatives (methylparaben; ethylparaben: benzylparaben; propylparaben); 2 antimicrobial agents (triclocarban and triclosan) and 5 UV filters (2,4-dihydroxybenzophenone; 2,2-dihydroxy-4-methoxybenzophenone; benzophenone-3; octocrylene and octyldimethyl-p-aminobenzoic acid) in environmental waters in only 9 run minutes of chromatographic separation. The SPE was carried out with two polymeric cartridges (Oasis HLB and Bond Elut Plexa). The recoveries obtained with Bond Elut Plexa were between 69% and 101% for 500 mL of river waters, with the exception of octyldimethyl-p-aminobenzoic acid (46%). Limits of detection for 500 mL of river water were in the range of 1-5 ng/L Oasis HLB was chosen for wastewater samples with recoveries between 38% and 92% (250 mL of effluents) and 36-89% (100 mL of influents). In both wastewater samples, octyldimethyl-p-aminobenzoic acid and methylparaben showed the lowest recoveries (20% and 27%). The method revealed benzophenone-3 as having the highest concentration levels (7 ng/L) in river waters. Most of PCPs determined were found in influent waters being methylparaben and propylparaben the ones found at highest concentration with values of 5613 and 1945 ng/L, respectively. In effluent waters, significant lower levels of some PCPs were found, being benzophenone-3 the one found at the highest concentration (100 ng/L).
A novel two-step extraction technique combining cloud point extraction (CPE) with dispersive micro-solid phase extraction (D-μ-SPE) is presented in this work for the first time. The method involves initial extraction of the target analytes by CPE in the micelles of a non-ionic surfactant medium; then highly hydrophobic polysiloxane-coated core-shell Fe _2O _3@C magnetic nanoparticles (MNPs) are used to retrieve the micellar phase. In that manner, the micellar phase containing the analytes is the target of the D-μ-SPE step rather than the analytes directly. MNPs are then collected by the application of an adscititious magnetic field overcoming the need for specific steps associated with CPE such as centrifugation to separate the surfactant-rich phase, refrigeration of the condensed micellar phase to reduce its viscosity or appropriate apparatus that enable direct sampling of the surfactant-rich phase. A noteworthy feature of the method is the introduction of highly oleophilic MNPs, which afford rapid and quantitative mass transfer of the surfactant phase, as opposed to other more conventional hydrophobic nanoparticles. In that manner, fast and reproducible extraction is accomplished, lending improved analytical features compared to conventional CPE, such as reduced analysis time and relative inertness to surfactant concentration and equilibration temperature. The analytes were recovered from the surface of MNPs by ultrasound-assisted back-extraction in a water-immiscible organic solvent where analytes are readily partitioned but the surfactant has limited solubility, thus minimizing its interference during chromatographic detection. As an analytical demonstration, different UV absorbing chemicals with various physico-chemical properties were used as model organic compounds for optimizing the parameters associated with this novel two-step extraction approach. The proposed method, combining two different and efficient techniques, offers satisfactory analytical features in terms of repeatability (4.5-7.5%), reproducibility (7.0-14.9%) and accuracy (88.5-97.2%). Most importantly it poses as an alternative and fast method for sample pretreatment opening new insights in surfactant-mediated extractions.
The determination of organic contaminants in soil is a real challenge due to the large number of these compounds with quite different physico-chemical properties. In the present work, an analytical method was developed for the simultaneous determination in soil of 40 organic contaminants belonging to different chemical classes: polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polybrominated diphenyl ethers, UV filters, parabens, bisphenols and triclosan. Soil was extracted by pressurized liquid extraction and the extracts, without the need of a clean-up step, were analyzed by gas chromatography-tandem mass spectrometry after in situ derivatization in the gas chromatographic system. In the pressurized liquid extraction step, two extraction cycles were performed with a mixture of ethyl acetate-methanol (90:10, v/v) at 80°C. Recovery of these contaminants from soil samples spiked at levels ranging from 30 to 120ngg ~(-1) was satisfactory for most of the compounds. The developed procedure provided detection method limits from 0.1 to 2.5ngg ~(-1). The analysis of soil samples collected in different agricultural fields confirmed the presence of some of the studied contaminants. Polycyclic aromatic hydrocarbons were the main contaminants detected, parabens and polychlorinated biphenyls were also found but at relatively low concentration levels, 2-ethylhexyl salicylate was the UV filter that appeared most frequently at levels ranging from 17.2 to 43.4ngg ~(-1) and triclosan was found in eight out of fourteen samples, at relatively low concentration levels (0.8-28.6ngg ~(-1)).