Determination Of Styrene Research Articles

Determination of styrene monomer migrating in foodstuffs from polystyrene food contact articles using HS-SPME-GC-MS/MS: Results from the Greek market

ABSTRACT In this study, a sensitive, accurate and fast headspace – solid phase microextraction – gas chromatography – tandem mass spectrometry method (HS-SPME-GC-MS/MS) was developed and validated for the determination of styrene in various food matrices (mean recovery ranged from 90 to 116% with a relative standard deviation of ≤11%). The method was used for the determination of the concentration of styrene in 23 foodstuffs packed in polystyrene (PS) containers, as well as the levels of styrene migrating into various foods (water, milk, cheese or cream) from 14 tableware or kitchenware articles made of styrene plastics. All samples were collected from the Greek market in 2020. Styrene concentrations in the packaged foods ranged from 0.4 to 160 ng g−1 with the highest concentration found in a meat product packed in a foamed PS tray. It is worth noting that 56% of PS packaged dairy products and desserts had a styrene concentration higher than 10 ng g−1. Particularly high levels of styrene that have not previously been reported, up to 46 ng g−1, were found in dairy products for children. The highest level of styrene migration from tableware or kitchenware articles, 89 ng g−1, was observed when disposable cups from foamed PS were filled with milk at 70℃ for 2 hours. The implications of these findings for the assessment of the potential exposure of the Greek consumers to styrene migrating from PS food contact materials are discussed.

A rapid extraction of toxic styrene from water and wastewater samples based on hydroxyethyl methylimidazolium tetrafluoroborate immobilized on MWCNTs by ultra-assisted dispersive cyclic conjugation-micro-solid phase extraction

The styrene affected on human health and caused cancer and dysfunction in the central nervous system (CNS) and liver. So, sensitive techniques for the separation and determination of styrene in water and wastewater samples are necessary. In this study, a novel task-specific ionic liquid (TSIL) immobilized on multi-walled carbon nanotubes (MWCNTs@[Hemim][BF4]) was synthesized with a new approach for extraction of styrene from water samples by ultra-assisted dispersive cyclic conjugation-micro-solid phase extraction procedure (USA-DCC-µ-SPE). Due to procedure, 30 mg of MWCNTs@[Hemim][BF4] was mixed with 20 mL of water or standard styrene solution (0.001–6.5 mg L−1) in the centrifuge Pyrex tube (CPT, 20 mL) by stirring for 12 min (25 °C). After extraction of styrene based on the cation/anion π–π interactions and imidazolium ring of TSIL with π system/vinyl group of styrene, the MWCNTs@[Hemim][BF4] adsorbents were collected at the bottom of the conical tube. The upper liquid phase set aside by the auto-sampler and 0.2 mL of ethyl benzene added to the remained solid phase at 70 °C. After back extraction of styrene in ethyl benzene, the styrene values were measured with a gas chromatography-flame ionization detector (GC-FID). All effective parameters such as the sample volume, the amount of sorbent, temperature, and the sonification time were studied. The linear range (LR), the detection limit (LOD) and re-usage of adsorbent were obtained 0.001–6.5 mg L−1, 0.26 μg L−1 and 18 times, respectively (r = 0.9997, RSD%=1.45). Due to TGA curve, the weight loss (7 wt%) for MWCNTs@[Hemim][BF4] was occurred at more than 350 °C. The absorption capacities of MWCNTs@[Hemim][BF4] and MWCNTs for 100–200 mg L−1 of standard styrene solution were obtained 183.2 mg g−1 and 24.8 mg g−1, respectively. The procedure was validated by GC–MS and spiking samples.

Improved determination of styrene with a titanium (IV) oxide film optical waveguide doped with zinc ferrite

Herein, a surface-sensitive sensor was reported as an optical waveguide (OWG) gas sensor. The sensor exhibited some advantages, including simple preparation and high sensitivity. Further, it could be operated at room temperature. TiO2 and ZnFe2O4 were employed as sensitive materials to prepare a sensor with a high response to styrene gas. The TiO2–ZnFe2O4 sol was prepared by doping ZnFe2O4 via the preparation of a TiO2 thin film, and the TiO2–ZnFe2O4 sol was fixed at the surface of the tin-doped glass waveguide by the dip-pulling method. Furthermore, the optimum conditions of the sensor were studied, and the sensors that were prepared under optimum conditions were employed to detect different concentrations of styrene gases. The results demonstrated that the sensor exhibited a high response to the determination of styrene and was reusable. Moreover, it could detect styrene across the concentration range from 1,000 ppm to 100 ppb at ambient temperature.

Rapid Analysis of Styrene in Drinking Water and Tea Samples Using Dispersive Liquid-Liquid Microextraction Combined with Liquid Chromatography-Ultraviolet Detection

In this project, a simple, low-cost and rapid procedure based on dispersive liquid–liquid microextraction (DLLME) technique coupled with high performance liquid chromatography-ultraviolet detector (HPLC-UV) has been used for the extraction and determination of styrene in aqueous solutions. Several factors, such as type of extraction and dispersive solvents and their volumes, salt addition, and pH were optimized. Under optimal conditions, the recoveries of styrene for tea and water samples spiked with 10 and 15 ng mL−1 were in the range of 91.4–97.8 %, whereas the temperature was set at 0, 4, 20, 70 and 91 °C for 15, 30, 60, 1440, and 14,400 min. The linear range was obtained in the interval of 1.86–50 ng mL−1. The limits of detection (S/N = 3) and quantitation (S/N = 10) were 0.6 and 1.86 ng mL−1, respectively. The relative standard deviations (RSDs) for three replicated analysis of styrene in aqueous samples ranged from 0.01 to 0.3 %.

Reactivity ratio determination of styrene and 2-ethylhexyl acrylate by least squares methods

The reactivity ratios of styrene (STY) and 2-ethylhexyl acrylate (EHA) synthesized by bulk copolymerization method, were determined by ordinary least square (OLS) and generalized least square (GLS) approaches according to Inverted Finemann - Ross (IFR), Yezrielev - Brokhina - Roskin (YBR), Kelen - Tudős (KT) methods. Composition results were summarized and the 95 % individual confidence limits were determined and compared with each other and Error - in - Variables - Model (EVM) approach. Based on the copolymer compositions, the calculated reactivity ratios of STY and EHA through the GLS approach show acceptable percentage deviation with the well-known EVM method, which proves GLS approach, is the best linear estimator program for determining the monomer reactivity ratios. The reactivity ratios of EHA and STY are equal to 0.292 and 0.980 in IFR technique through the generalized least squares (GLS) approach which is closer to the point estimated from Error-in-variables model (EVM) and also r EHA and r STY are equal to 0.292 and 0.979 in EVM method, respectively. The present paper shows an estimation integral method for investigating the reactivity ratios of styrene and 2-ethylhexyl acrylate in Eviews software and the estimated values are discussed in terms of two regression approaches and compared with EVM method.

Development of a miniaturized diffusive sampler for true breathing-zone sampling and thermal desorption gas chromatographic analysis

Exposure measurements should be performed as close as possible to the nose and mouth for a more correct assessment of exposure. User-friendly sampling equipment, with a minimum of handling before, during and after measurement, should not affect ordinary work. In diffusive (passive) sampling, no extra equipment as sampling pumps is needed, making the measurements more acceptable to the user. The diffusive samplers are normally attached on a shoulder, on a breast-pocket or on the lapel. There are, however, difficulties if true breathing-zone sampling is to be performed, since available diffusive samplers normally cannot be arranged close to the nose/mouth. The purpose of this work was to study the performance of a miniaturized tube type diffusive sampler attached to a headset for true breathing-zone sampling. The basis for this miniaturization was the Perkin Elmer ATD tube. Both the size of the tube and the amount of adsorbent was decreased for the miniaturized sampler. A special tube holder to be used with a headset was designed for the mini tube. The mini tube is thermally desorbed inside a standard PE tube. The new sampler was evaluated for the determination of styrene, both in laboratory experiments and in field measurements. As reference method, diffusive sampling with standard Perkin Elmer tubes, thermal desorption and gas chromatographic (GC) analysis was used. The sampling rate was determined to 0.356 mL min(-1) (CV 9.6%) and was not significantly affected by concentration, sampling time or relative humidity.

SPE–GC–MS for the sampling and determination of unmetabolized styrene in urine☆

The urinary excretion of unmetabolized styrene can be a very good indicator for biomonitoring styrene in occupationally exposed people. The use of a new urine sampling system, involving a solid-phase extraction cartridge, offers several advantages for determining styrene. The advantages are especially related to the pre-analytical phase of styrene determination, which may be influenced by many variables. The effect on styrene recovery of sorbent type, eluting solvent, elution volume, elution flow-rate, and the addition of methanol to the washing solvent, was evaluated by experimental design methodology. As a result, Oasis HLB cartridges were selected for urine sampling, as well as 1.5 mL of ethyl acetate at 0.5 mL/min for eluting the retained styrene. These conditions were then applied to the validation of the solid-phase extraction combined with GC-MS method for the sampling and analysis of unmetabolized styrene in urine. The overall uncertainty was in the 12-22% range and the limit of detection was 2.2 microg/L for a 4 mL urine sample. The stability of styrene has been studied both in cartridges and in vials under different storage periods. After 1 month period the styrene stored on cartridges at room temperature remained stable, whereas this is not the case for styrene recovery from vials. The results obtained indicate that on-site solid-phase extraction of urine can provide a simple, accurate and reproducible sampling and analytical method for the biomonitoring of styrene in urine.

Sensitive determination of styrene and related compounds in human body fluids by headspace capillary gas chromatography with cryogenic oven trapping

A simple and sensitive method is presented for determination of styrene, toluene, ethylbenzene, isopropylbenzene andn-propylbenzene in human body fluids by capillary gas chromatography (GC) with cryogenic oven trapping. After heating a blood or urine sample containing each compound andp-diethylbenzene (internal standard, IS) in a 7.0-mL vial at 60°C for 20 min, 5 mL of headspace vapor was drawn into a glass syringe and injected into a GC. All vapor was introduced into an Rtx-Volatile middle bore capillary column in splitless mode at oven temperature of 20°C to trap entire analytes, and the oven temperature then programmed to 280°C for GC measurements by flame ionization detection. The present conditions gave sharp peaks of each compound and IS, and low background noises for whole blood or urine samples.

Determination of styrene and styrene additives using cylindrical microelectrodes in acetone

Cylindrical carbon fibre microelectrodes (CFMEs) (8 mm in diameter, 8 mm in length) were used to develop voltammetric methods for the determination of the antioxidant 4-tert-butylcatechol (TBC) in styrene, and of styrene in polystyrene samples. Acetone, containing 0.01 mol l−1 sodium perchlorate as supporting electrolyte, was selected as a suitable working medium. A good adjustment of the voltammetric responses to that predicted by the theory was found. Reproducible electroanalytical responses were obtained with no need of applying cleaning treatments to the CFME. Using square-wave voltammetry (SWV), linear calibration graphs were obtained for TBC and styrene in the 1.0 × 10−6–1.0 × 10−4 mol l−1 range, with detection limits of 4.3 × 10−7 mol l−1 and 4.0 × 10−7 mol l−1, respectively. The sensitivity of the method for styrene was around four orders of magnitude better than that reported for another microelectrode-based electroanalytical method. Voltammograms from mixtures of TBC and styrene showed two well-defined oxidation peaks with a difference between the peak potentials of 600 mV. Commercial styrene samples containing 0.005% of TBC were analyzed with good results. In addition, the method was applied to the determination of styrene in spiked polystyrene yoghurt packagings.

Parts‐per‐trillion determination of styrene in yoghurt by purge‐and‐trap gas chromatography with mass spectrometry detection*

Headspace sampling methods prior to capillary gas chromatography have been widely used for the determination of volatile compounds present in very different kinds of samples. This paper describes an automated and rapid system to determine volatiles from yoghurt. Thirty‐five volatile organic compounds (VOCs) were identified in polystyrene cups used for yoghurt packaging and 42 VOCs from yoghurt samples. Quantitation of styrene in several samples from the Spanish retail market was carried out.

Single-Measurement Excitation/Emission Matrix Spectrofluorometer for Determination of Hydrocarbons in Ocean Water. 2. Calibration and Quantitation of Naphthalene and Styrene

An excitation/emission matrix imaging spectrofluorometer was employed for quantitation of two fluorescent compounds, naphthalene and styrene, contained in ocean water exposed to gasoline. Multidimensional parallel factor (PARAFAC) analysis models were used to resolve the naphthalene and styrene fluorescence spectra from a complex background signal and overlapping spectral interferents not included in the calibration set. Linearity was demonstrated over 2 orders of magnitude for determination of naphthalene with a detection limit of 8 parts per billion. Similarly, nearly 2 orders of magnitude of linearity was demonstrated in the determination of styrene with an 11 ppb limit of detection. Furthermore, the synthesis of the EEM spectrofluorometer and the PARAFAC analysis for unbiased prediction of naphthalene and styrene concentration in mixture samples containing uncalibrated spectral interferents was demonstrated.

Determination of styrene in olive oil by an automatic purge-and-trap system coupled to gas chromatography-mass spectrometry

A new gas chromatographic method using an automatic purge-and-trap system coupled to a GC with mass selective detection to analyze styrene at the parts-per-trillions (ng kg−1) level is described. The method shows a good sensitivity and the detection limit is 10 ng kg−1 with a relative standard deviation (RSD) of 4.7% for 164 ng kg−1 styrene in olive oil. This analytical method has been successfully applied to the analysis of styrene in extra-virgin olive oil from the European market.

Determination of styrene in olive oil by an automatic purge-and-trap system coupled to gas chromatography-mass spectrometry

Determination of styrene in olive oil by an automatic purge-and-trap system coupled to gas chromatography-mass spectrometry

Determination of styrene in selected foods

Styrene levels in 12 commodities were determined. The foods tested were wheat, oats, peanuts, pecans, coffee beans, tomatoes, peaches, strawberries, cinnamon, beef, chicken, and milk. The samples were collected in a manner that avoided contact with styrene or any type of plastic. Analytical measurements were performed using a dynamic heated headspace purge-and-trap extraction technique followed by quantification by selected ion monitoring capillary gas chromatography/mass spectrometry. Method blanks, duplicate samples, and samples fortified with benzene and styrene were used to assess method performance. The limit of detection of the method varied between food types but was generally less than 2 ng/g for styrene. The highest measured concentrations of styrene were found in cinnamon (169-39200 ng/g). Styrene concentrations in beef samples ranged from 5.25 to 7.85 ng/g and in coffee beans from 1.57 to 7.85 ng/g. Wheat, pecans, oats, strawberries, and peaches showed no styrene concentrations greater than 3 ng/g. No detectable styrene was found in tomatoes, milk, or chicken

Determination of styrene in olive oil by coevaporation, cold trap, and GC/MS/SIM

A new procedure to determine styrene in olive oil, a simulant of fatty food, is presented. The method is bred on the coevaporation of styrene with a solvent of low boiling point at 90 o C. The vapors obtained are condensed in a frozen syringe, and this liquid is injected in GC/MS/SIM mode. The method hr been validated using deuterated styrene (d s ) and α-methylstyrene as internal standards. The detection limit is 10 μg/kg with a relative standard deviation (RSD) of 5% for 50 μg/kg styrene in olive oil

Determination of styrene and 2-vinylpyridine monomers in poly(2-vinylpyridine—styrene)

Residual monomers such as styrene can be determined in polymers at microgram per kilogram concentrations by headspace techniques. However, such techniques often do not have adequate sensitivity for the determination of monomers less volatile than styrene. A method is described for the determination of trace concentrations of monomers that are less volatile than styrene and also monomers that are traditionally determined in polymers by headspace techniques. The method involves dissolution of the polymer, removal of the polymer by molecular ultrafiltration and determination of the monomer in teh filtrate by gas chromatography—mass spectrometry. Concentrations of styrene and 2-vinlpyridine of less than 200 μg/kg were successfully determined in a copolymer used for the post-ruminal delivery of nutritional supplements and drugs.

Human Granulocyte LTB4 Production and Respiratory Burst Impaired by Styrene

Human granulocytes (PMN) incubated in vitro with styrene at a concentration of 3.3 x 10-4 M have shown an impairment of leucotriene B4 (LTB4) production and of respiratory burst after stimulation with N-formyl-methyonil-leucyl-phenylalanine peptide (nFMLP), which has a specific membrane receptor. The level of impairment in LTB4 production was lower in cells pretreated for 15 minutes with styrene than in cells treated with styrene and nFMLP simultaneously. Styrene did not cause irreversible damage, because 15 minutes after styrene treatment PMN partially recovered their function. The determination of styrene and styrene oxide, the presumed active metabolite, in the supernatant of cell culture, showed that styrene rapidly enters the cell and only 15 minutes or more after styrene addition was styrene oxide found. On this basis, the action of styrene does not seem to be mediated by metabolites.

Determination of styrene in biological samples by reversed-phase liquid chromatography

Determination of styrene in biological samples by reversed-phase liquid chromatography

Determination of styrene in the urine of workers manufacturing polystyrene plastics.

Styrene exposure was monitored in humans by following the urinary excretion of unmodified styrene. With values of styrene in the work environment ranging from 16 to 61 mg m −3 , urinary concentrations of styrene (with two exceptions that were negative) ranged from 0.7 to 4.1 μg l −1 . No styrene was found in control urine. Urinary mutagenic activity of the same samples was measured using Salmonella typhimurium strains TA 1538 and TA 100, with and without metabolic activation. No increase of mutagenic activity was observed over controls. Styrene level in the urine, and not urinary mutagenic activity, is an index of exposure to styrene in the workplace.

Determination of styrene in foods by reversed-phase high-performance liquid chromatography

Determination of styrene in foods by reversed-phase high-performance liquid chromatography