Preparation of a magnetic phosphazene-based hyper crosslinked polymer for the fast and efficient extraction of chlorophenols from water and peach juice.

Two magnetic phosphazene-based hyper crosslinked polymers (M-HCP-OP-TMC and M-HCP-OP-TCL) were newly synthesized by the reaction of Friedel-Crafts acylation, and the M-HCP-OP-TMC showed an excellent extraction capability and rapid adsorption kinetics for chlorophenols as an adsorbent. Then, an efficient analytical method was built for the preconcentration and quantification of chlorophenols from water and peach juice samples by combining M-HCP-OP-TMC based magnetic solid-phase extraction (MSPE) with HPLC-UV detection. The linear response range for the chlorophenols by the method was 0.21-100.0 ng mL-1 for water sample, and 0.36-100.0 ng mL-1 for peach juice sample. The detection limits (S/N = 3) of the proposed method for the analytes were 0.07- 0.25 ng mL-1 and 0.12-0.45 ng mL-1 for water and peach juice samples, respectively. The method recoveries for the spiked samples were in the range of 93.1%-117.1%, and the relative standard deviations were less than 10%. The adsorption of the chlorophenols with the M-HCP-OP-TMC was mainly contributed by π-π stacking and hydrophobic interactions. The results indicate that the method was sensitive and accurate enough for the determination of the chlorophenols from real samples.

Development of methods based on low-temperature partitioning (LTP) for monitoring cresols and chlorophenols in sewage sludge, soil, and water in column leaching.

Cresols and chlorophenols are chemical contaminants that are potentially toxic to humans and can be found in sewage sludge. These chemical contaminants can migrate into the sludge-soil-water system when sludge is used as a conditioner for agricultural soils. Thus, the objective of this study was to develop methodologies based on extraction with low-temperature partitioning (LTP) to determine cresols and chlorophenols in sewage sludge, soil, and water. The analysis was performed by gas chromatography coupled with mass spectrometry (GC-MS). The validated methods were applied to monitor cresols and chlorophenols in a column-leaching study of a sludge-soil-water system. Satisfactory results were achieved for selectivity, limit of quantification (LOQ), linearity, accuracy, and precision. In the column leaching study, only 2,4,6-trichlorophenol was quantified in sludge samples after 20 days of the experiment. None of the studied compounds were quantified in soil and leached water samples, due to the degradation promoted by the microorganisms present in the sewage sludge. Finally, validated methods were suitable for monitoring cresols and chlorophenols in the sludge-soil-water system.

The reaction pathway and mechanism of 2,4-dichlorophenol removal by modified fly ash-loaded nZVI/Ni particles.

Nanoscale zero-valent iron (nZVI) is more valuable in environmental restoration than other materials. Chemical treatment of fly ash (CFA) was employed as a support material to disperse iron nickel bimetal nanoparticles (CFA-nZVI/Ni) to remove 2,4-dichlorophenol (2,4-DCP). Batch experiments showed that 2,4-DCP was completely removed by CFA-nZVI/Ni, and an optimal loading ratio was 8:1. The degradation of 2,4-DCP by CFA-nZVI/Ni was a chemical control reaction with an activation energy of 95.6 kJ mol-1 and followed pseudo-first-order kinetics. The addition of Cl- increased the removal rate of 2,4-DCP by 4%, while the addition of CO32- and SO42- decreased the removal rate of 2,4-DCP by 32% and 72.3%, respectively. The removal process of 2,4-DCP by CFA-nZVI/Ni included adsorption and reduction. The 2-CP (7.1 mg/L) and 4-CP (11.6 mg/L) could be converted to phenol using the CFA-nZVI/Ni system. Cl on the para-position of 2,4-DCP was simpler to remove than on the ortho-position. The following steps were taken in the electrophilic substitution reaction between substituted phenols and hydrogen radicals: 2,4-DCP > 2-CP > 4-CP > phenol. This research provides a novel concept to effectively remove 2,4-DCP and mechanism analysis.

Keggin type phosphotungstic acid intercalated copper-chromium-layered double hydroxide reinforced porous hollow fiber as a sorbent for hollow fiber solid phase microextraction of selected chlorophenols besides their quantification via high performance liquid chromatography.

Herein, a copper-chromium-layered double hydroxide (Cu/Cr-LDH) was synthesized by the co-precipitation method. The Cu/Cr-LDH was intercalated to the Keggin-type polyoxometalate (H3PW12O40). The modified LDH accommodated in the pores of hollow fiber (HF), to prepare the extracting device for the HF-solid phase microextraction method (HF-SPME). The method was used for the extraction of 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6- trichlorophenol from tap water, river water, and tea sample. The extracted target analytes were quantified via high-performance liquid chromatography-UV detection. The figures of merit of the method such as, linear dynamic ranges (LDRs), limit of detections (LODs) and, limit of quantifications (LOQs), were determined based on the obtained optimum condition. Based on the results, the LDR was between 1 and 500 µg L - 1 and r2 higher than 0.9960. The LODs and LOQs were obtained in the ranges of 0.28-0.36 µg L - 1 and 0.92-1.1 µg L - 1, respectively. The relative standard deviations ((RSDs% for inter-and intra-day) of the method for the extraction of target analytes were calculated in two different concentrations of (2 and 10 µg L - 1) and (5 and 10 µg L - 1) between 3.70% - 5.30% and 3.50% - 5.70%-respectively. The enrichment factors were obtained between 57 and 61. In order to investigate the accuracy of the method, also the relative recovery was obtained, between 93 and 105%. Finally, the proposed method was used for the extraction of the selected analytes in different water and tea samples.

Porous agarose/chitosan/graphene oxide composite coupled with deep eutectic solvent for thin film microextraction of chlorophenols.

In this project, a three-dimensional graphene oxide coated agarose/chitosan (ACGO) porous film was synthesized and utilized as sorbent in thin film microextraction (TFME) technique to extract 4-chlorophenol, 2,4-dichlorophenol, 3,5-dichlorophenol and 2,4,6-trichlorophenol as the model analytes in various real samples such as agricultural waste water, honey and tea samples. In addition, deep eutectic solvent made of tetra ethyl ammonium chloride/chlorine chloride was used as a desorption solvent. The effect of various variables, such as: extraction time, stirring rate, solvent desorption volume, desorption time, ionic strength and solution pH on the extraction efficiency of the method was studied and optimized. Under the optimized condition, the linear range of the method was obtained in the range of 0.1-500µgL-1 for testing analytes (4-chloropheol=0.1-500µgL-1, 2,4-dichlorophenol=0.2-500µgL-1, 3,5-dichlorophenol=0.5-500µgL-1 and 2,4,6-trichlorophenol=0.2-500µgL-1). The obtained correlation coefficients (r2) were between 0.9984 and 0.9994. The limits of detection (LODs) were also calculated between 0.03 - 0.13µgL-1. The relative standard deviations (RSDs%) were obtained in the range of 2.8 to 5.9%. The enrichment factor (EFs) values for the studied analytes were also obtained in the range of 33.4-35.8. In addition, the obtained results indicated that the prepared film can potentially be used for more applications in the field of environment, food safety, and drug analysis.

Piperazine-linked metal covalent organic framework-coated fibers for efficient electro-enhanced solid-phase microextraction of chlorophenols.

Conductive covalent organic frameworks (COFs) have received considerable attention and are critical in various applications such as electro-enhanced solid-phase microextraction (EE-SPME). In this work, a novel piperazine-linked copper-doped phthalocyanine metal covalent organic framework (CuPc-MCOF) was synthesized with good stability and high electrical conductivity. The synthesized CuPc-MCOF was then used as an EE-SPME coating material for extraction of five trace chlorophenols (CPs), including 2,4-dichlorophenol (2,4-DCP), 2,6-dichlorophenol (2,6-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,4,5-trichlorophenol (2,4,5-TCP) and 2,4,5,6-tetrachlorophenol (2,4,5,6-TCP), exhibiting excellent extraction performance because of various synergistic forces between CuPc-MCOF fibers and CPs. By combining EE-SPME with gas chromatography-tandem mass spectrometry (GC-MS/MS), a sensitive method for CPs detection was established with a low limit of detection (0.8-5 ng L-1) and good reproducibility (RSD≤8.4%, n = 3). This method was then successfully applied to the analysis of trace CPs in real samples of seawater and seafood. Results showed that the developed CuPc-MCOF coating material possessed superior extraction performance and potential application in extraction of trace polar pollutants from complex samples.

Sustainable and green synthesis of porous organic polymer for solid-phase extraction of four chlorophenols in water and honey.

A novel hypercrosslinked polymer (API-HCP) was synthesized using as monomer for the first time. API-HCP exhibited high adsorption affinity toward chlorophenols due to the hydrogen bond, halogen bond and π-stacking interactions. With API-HCP as adsorbent, an efficient solid phase extraction method coupled with high performance liquid chromatography (SPE-HPLC) was established for the sensitive detection of chlorophenols in water and honey samples. Under the optimum conditions, the method provided a good linear response in the range of 0.07-100 ng mL-1 for water and 1.7-500 ng g-1 for honey sample. High sensitivity was achieved, with detection limits (S/N = 3) of 0.02-0.07 ng mL-1 for water and 0.5-1.5 ng g-1 for honey samples. The method recoveries for spiked sample were between 84.0 % and 116.0 %, with relative standard deviations ≤6.1 %. The API-HCP based SPE-HPLC method provided a robust platform for sensitive determination of chlorophenols in water and honey samples.

A carbazole-based spherical microporous polymer for the solid-phase extraction of chlorophenols from water and honey samples.

A new carbazole-based spherical microporous polymer (Car-BDA-POP) was fabricated by employing 4,4'-biphenyldicarboxaldehyde (BDA) and carbazole as monomers via a one-step and non-metal catalyst synthetic approach. It was then explored as an adsorbent for solid-phase extraction (SPE) of some chlorophenols (CPs). Under the optimized extraction conditions, the established Car-BDA-POP-based SPE coupled with high-performance liquid chromatography ultraviolet detection showed good linearity in the concentration range of 0.1-200 ng mL-1 for water samples and 5.0-800 ng g-1 for honey samples with the determination coefficients (r2) ≥ 0.9995 for the analytes. The limits of detection (S/N = 3) for the analytes were in the range of 0.03-0.06 ng mL-1 for water samples and 1.50-2.50 ng g-1 for honey samples. The method recoveries varied from 80.0 % to 116 % in spiked real samples, with the relative standard deviations less than 9.6 %. In addition, the possible adsorption mechanism, adsorption kinetics, and adsorption isotherms were also investigated.

Modified activated carbon derived from chestnut oak shells as a new sorbent for the needle-trap extraction.

In this study, an acid-treated-activated carbon was prepared from chestnut oak shell carbonization followed by modification with hydrochloric acid/nitric acid and then used as a new sorbent for headspace needle-trap extraction of chlorophenol compounds from aqueous solutions. Different techniques, including scanning electron microscopy, nitrogen adsorption-desorption analysis, and Fourier transform-infrared spectroscopy were used for the characterization of the sorbents. The effects of some experimental parameters, including the temperature, pH, sorbent amount, and time of extraction were optimized. The developed method is fast and sensitive, providing low and sub ng/L detection limits. The limits of detection and quantification were in the range of 0.75-5 and 5-15 ng/ml, respectively, and the equilibrium time was 20 min. Wide linearity in the range of 15-2000 ng/L with R2  > 0.9993 was obtained. Repeatability of the method was accessed at 50, 100, and 200 ng/L concentration levels and RSD% of 5%-12% was achieved. The introduced method was applied for analyzing real water samples containing spiked chlorophenols, and the relative recovery values were found to be in the range of 84%-99% at the concentration levels of 50, 100 and 200 ng/L.

Facile fabrication of hydroxyl-functionalized hypercrosslinked polymer for sensitive determination of chlorophenols.

Three hydroxyl-functionalized hypercrosslinked polymers (HCP-POL, HCP-HQ and HCP-PG) were synthesized by Friedel-Crafts reaction. The HCP-HQ displayed the largest surface area and highest adsorption capacity for chlorophenols (CPs). Thus, the HCP-HQ was further modified with magnetism to obtain M-HCP-HQ. An efficient magnetic solid-phase extraction method with M-HCP-HQ as adsorbent was developed for the first time to simultaneously extract four CPs from water and honey samples before analysis by high performance liquid chromatography-diode array detection. Under optimized conditions, the low detection limits (S/N = 3) were obtained to be 0.06-0.10 ng mL-1 for water and 0.80-1.75 ng g-1 for honey. The method recovery was 80.7%-119%, with relative standard deviations below 9.5%. The enrichment factors of the CPs were in the range of 57-220. The extraction mechanism could be attributed to the strong polar interaction, hydrogen bonding and π-π interactions between the M-HCP-HQ and CPs. The M-HCP-HQ based method can be served as a reliable and sensitive tool for detection CPs in water and honey samples.

Effective solid-phase extraction of chlorophenols with covalent organic framework material as adsorbent.

In this work, a porous extended network covalent organic framework designated as TP-NDA-COF was synthesized by the reaction of 2,4,6-trihydroxy-benzene-1,3,5-tricarbaldehyde (TP) and 1,5-naphthalenediamine (NDA). The structure and morphology of the TP-NDA-COF was characterized by means of Fourier transform infrared spectra (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The TP-NDA-COF was applied as a solid-phase extraction adsorbent for the extraction of some chlorophenols from water and lemon black tea beverage samples prior to high performance liquid chromatography-UV detection. The main experimental parameters that affect the extraction efficiency including the type and volume of eluent, sample solution volume, sample loading rate and sample solution pH were investigated. Under the optimal conditions, the calibration curves were linear in the range of 0.30-60.0 ng mL-1 with the determination coefficients (R2) of 0.9996-0.9998 for water samples and in the range of 0.60-60.0 ng mL-1 with the R2 values from 0.9990 to 0.9996 for beverage samples. At the signal to noise ratio of 3 (S/N = 3), the method LODs for the analytes were 0.10-0.15 ng mL-1 for water samples and 0.20-0.50 ng mL-1 for lemon black tea beverage, respectively. Good repeatability was achieved with the relative standard deviations of less than 7%. The results showed that the SPE-HPLC method can be used for the determination of chlorophenols in environmental water and foodstuffs samples.

[Determination of 19 chlorophenols in fish by QuEChERS-gas chromatography-mass spectrometry].

With the increasing use of chlorine-containing pesticides, hypochlorous acid disinfection water as well as aquatic product insecticides and fungicides are widely used in the cultivation of fish. This has led to the contamination of fish by chlorophenol compounds. However, currently, there is no standard method for the simultaneous determination of 19 chlorophenol compounds in fish. In this study, the optimum chromatography and mass spectrometry conditions were determined by investigating the instrument parameters. The 19 chlorophenol compounds were well separated using the DB-5MS capillary chromatographic column (30 m×0.25 mm×0.25 µm) with a carrier gas flow rate of 1 mL/min. Under this condition, the chromatographic peak was sharp and symmetric. An analytical method was developed for the simultaneous determination of the 19 chlorophenol compounds in fish using gas chromatography-mass spectrometry coupled with QuEChERS pretreatment. The improved QuEChERS method was used in sample preparation. The 19 chlorophenol compounds were extracted with organic solvents and purified with purifying agents. During the experiment, the effect of the kinds and volumes of the extraction solvent, as well as the types and dosages of the purifying agent, on the recoveries of the 19 chlorophenol compounds were investigated. Moreover, the temperature and time of derivatization, as well as the dosage of the derivatization agent, were optimized. All aforementioned analyses were conducted with the aim of determining the optimal pretreatment method. Finally, the optimized gas chromatography-mass spectrometry conditions were employed for the quantitative determination of 19 chlorophenol compounds in fish samples. Based on the experimental results, the best extraction method was determined to be the one where the extraction agent (10 mL ethyl acetate) was added to 3 g sodium chloride and 5 g anhydrous magnesium sulfate in the test tube, followed by ultrasonication for 15 min. The sample was centrifuged at 4500 r/min for 5 min, and 500 mg C18 was selected as the purifying agent to purify the supernatant. The purified supernatant was blown with nitrogen to less than 1 mL at 45 ℃, and then redissolved with ethyl acetate to 1 mL. Subsequently, the sample solution was passed through a 0.22 µm organic filter membrane, following which 50 µL bis(trimethylsilyl)trifluoroacetamide was added for derivatization at 45 ℃ for 30 min. Lastly, the 19 chlorophenol compounds were determined by gas chromatography-mass spectrometry with an electrospray ionization source and selecting ion monitoring mode. The 19 chlorophenol compounds were then quantitatively analyzed by the external standard method. The compounds showed good linearity in the concentration range of 0.4-10 µg/L, with correlation coefficients (R2) greater than 0.998. The limits of detection and limits of quantification were 0.01-0.05 µg/kg and 0.04-0.16 µg/kg, respectively. Moreover, the average recoveries of the 19 chlorophenol compounds were in the range of 70.6%-115.0% at three spiked levels, and the relative standard deviations were in the range of 2.6%-10.5%. The established method in this study was applied to detect and analyze chlorophenol compounds in actual samples. The experimental results showed that various levels of chlorophenol compounds could be detected in different fishes. Among them, the total amount of chlorophenol compounds detected in the Corvina was 8.74 µg/kg, followed by the Crucian carp at 7.59 µg/kg, and the minimum detected amount in rice fish (1.59 µg/kg). With its simple operation, high sensitivity, and good repeatability, the established method simplifies the pre-treatment of fish samples. It can also meet the requirements for the high-throughput detection of 19 chlorophenol compounds in fish, thereby significantly improving the detection efficiency of chlorophenols. Moreover, the method provides crucial technical support and a theoretical basis for the establishment of feasible detection standards for chlorophenols in China, as well as for the control of residue levels of chlorophenol compounds in fish. The findings have important practical significance to implement management measures during fish breeding and transportation.

Single bubble in-tube microextraction coupled with capillary electrophoresis.

Headspace (HS) extraction is a sample pretreatment technique for volatile and semivolatile organic compounds in a complex matrix. Recently, in-tube microextraction (ITME) coupled with CE using an acceptor plug placed in the capillary inlet was developed as a simple but powerful HS extraction method. Here, we present single bubble (SB) ITME using a bubble hanging to the capillary inlet immersed in a sample donor solution as a HS of submicroliter volume (∼200 nL). The analytes evaporated to the bubble were extracted into the acceptor phase through the capillary opening, then electrophoresis of the enriched extract was carried out. Since the bubble volume was much smaller than a conventional HS volume (∼1 mL), it was filled with the evaporated analytes rapidly and the analytes could be enriched much faster compared to conventional HS-ITME. Owing to the high surface-to-volume ratio of the SB, 5 min SB-ITME yielded the enrichment factor values similar to those of 10 min HS-ITME. When 5 min SB-ITME at room temperature was applied to a tap water sample, the enrichment factors of 2,4,6-trichlorophenol (TCP), 2,3,6-TCP, and 2,6-dichlorophenol were 53, 41, and 60, respectively, and the LOQs obtained by monitoring the absorbance at 214 nm were 5.6-8.3 ppb, much lower than 200 ppb, the World Health Organization guideline for the maximum permissible concentration of 2,4,6-TCP in drinking water.

Fabrication of carbonyl-functional hypercrosslinked polymers as solid-phase extraction sorbent for enrichment of chlorophenols from water, honey and beverage samples.

Three carbonyl-functional novel hypercrosslinked polymers (HCP-TPS, HCP-TPA, and HCP-TPP) were successfully fabricated through an one-step Friedel-Crafts acylation reaction by copolymerizing paraphthaloyl chloride with triphenylsilane, triphenylamine, and triphenylphosphine, respectively. The resultant HCPs contained plenty of carbonyl-functional groups. Among the series of such HCPs, HCP-TPS displayed the best adsorption capability to chlorophenols (CPs), and thus it was employed as solid-phase extraction (SPE) adsorbent for enrichment of chlorophenols from water, honey, and white peach beverage prior to determination by high-performance liquid chromatography. Under the optimal conditions, the detection limits of the method (S/N = 3) were 0.15-0.3 ng mL-1 for tap water and leak water, 2.5-6.0 ng g-1 for honey sample and 0.4-0.6 ng mL-1 for white peach beverage sample. The recoveries of CPs in the spiked water, honey samples, and white peach beverage were in the range of 89.0-108.4%, 81.4-118.2%, and 85.0-113.5%, respectively. This work provides a new strategy for constructing functionalized HCPs as efficient SPE adsorbents. In this work, three novel hypercrosslinked polymers (HCPs) were synthesized by the Friedel-Crafts alkylation reaction (paraphthaloyl chloride as the alkylating agent, triphenylsilane, triphenylamine, and triphenylphosphine as the aromatic units). Then, HCP-TPS was applied to soild-phase extraction sorbent for enrichment CPs from water, honey, and white peach beverage samples.

Plugged bifunctional periodic mesoporous organosilica as a high-performance solid phase microextraction coating for improving extraction efficiency of chlorophenols in different matrices.

In this study, a sensitive solid phase microextraction (SPME) coating was developed based on two kinds of plugged and non-plugged bifunctional periodic mesoporous organosilicas (BFPMO) with ionic liquid and ethyl units. The extraction efficiency of all plugged and unplugged sorbents was investigated for the extraction of chlorophenols (CPs) in water and honey samples by emphasizing the effect of different physicochemical properties. The separation and determination of the CPs was performed by gas chromatography-mass spectrometry (GC-MS). The extraction results showed that plugged BFPMO coating exhibited outstanding enrichment ability for the extraction of CPs as model analytes with different polarities. This can be attributed to a valuable hydrophobic-hydrophilic balance in the mesochanels of the plugged BFPMO, which is the result of the combination of plug technology and bridged organic groups. Low limits of detection in the range of 5-70 ng L-1, wide linearity, and good reproducibility (RSD = 8.1-10.1 % for n = 6) under the optimized extraction conditions were achieved. Finally, the BFPMOs coated fiber was successfully used for determination of CPs in real water samples. The relative recoveries for the five CPs were in the range of 92.3-104.0 %, which proved the applicability of the method.

Magnetic solid-phase extraction using polydopamine-coated magnetic multiwalled carbon nanotube composites coupled with high performance liquid chromatography for the determination of chlorophenols.

Polydopamine (PDA)-coated magnetic multiwalled carbon nanotube (M-MWCNT) composites were synthesized in two facile preparation steps, and were used as adsorbents for magnetic solid-phase extraction (MSPE) coupled with high-performance liquid chromatography (HPLC) for simultaneous extraction, enrichment and determination of five kinds of typical chlorophenols (CPs) in water samples. The as-prepared magnetic composites showed excellent magnetic properties and high thermal stability. Various main parameters influencing the extraction efficiency of MSPE were systematically investigated. Under the optimized MSPE-HPLC conditions, a high enrichment factor (EF) was obtained in the range of 85-112 for 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,6-dichlorophenol (2,6-DCP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP). Good linearity was obtained in the range of 2.0-200 µg L-1 for 2-CP and 4-CP and 1.0-200 µg L-1 for 2,6-DCP, 2,4-DCP and 2,4,6-TCP, with a correlation coefficient (R2) higher than 0.9964. The limits of detection (LODs) and the limits of quantification (LOQs) were in the range of 0.10-0.31 µg L-1 and 0.35-1.03 µg L-1, respectively. The intraday and interday precisions evaluated using relative standard deviation (RSD) values were in the range of 1.05-2.25% and 1.88-2.83%, respectively. The validated MSPE-HPLC method was also successfully applied to analyze five kinds of CPs in tap water, lake water, river water and seawater samples, and satisfactory recoveries were obtained in the range of 76.87-106.5% with RSDs of 1.64-6.78%.

Bikini textile contact dermatitis: A Sherlockian approach revealing 2,4-dichlorophenol as a potential textile contact allergen.

BACKGROUND: Different textile constituents may act as allergens and/or irritants and provoke textile contact dermatitis (TCD). OBJECTIVES: To report a case of TCD caused by ethylene glycol monododecyl ether and 2,4-dichlorophenol, present in a bikini. METHODS: A woman presented with an eczematous, pruritic rash in the area of the bikini straps and back. Patch testing was performed with the European baseline, textile, sunscreen, and photo-patch series, the bikini "as is", and ethanol and acetone extracts of the bikini. Thin-layer chromatography (TLC) of the extracts and gas chromatography-mass spectrometry (GC-MS) analysis were used to elucidate the culprit agents. RESULTS: Positive reactions were found to the bikini "as is" and to the ethanol and acetone extracts. Patch testing with TLC strips showed a strong reaction to spots-fractions 3 and 4. GC-MS was performed to identify substances in each fraction and those suspected to be skin sensitisers were patch tested. On day (D) 4 positive reactions to ethylene glycol monododecyl ether (irritant reaction) and 2,4-dichlorophenol (++) were observed. CONCLUSION: A myriad of chemical compounds can be found in clothing. Ethylene glycol monododecyl ether and 2,4-dichlorophenol were identified as the potential culprits of this bikini TCD.

Exposure to 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol and risk of thyroid cancer: a case-control study in China.

Thyroid cancer (TC) has inflicted huge threats to the health of mankind. Chlorophenols (CPs) were persistent organic pollutant and can lead to adverse effects in human health, especially in thyroid. However, epidemiological studies have revealed a rare and inconsistent relationship between internal exposure to CPs and TC risk. The purpose of this study was to investigate the correlation between urinary CPs and TC risk in Chinese population. From June 2017 to September 2019, a total of 297 histologically confirmed TC cases were recruited. Age- and gender-matched controls were enrolled at the same time. Gas chromatography-mass spectrometry (GC-MS) was used to determine the levels of three CPs in urine. Conditional logistic regression models were adopted to assess the potential association. Restricted cubic spline function was used to explore the non-liner association. After adjusting for confounding factors, multivariate analysis showed that, compared with the first quartile, the fourth quartile concentrations of 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) were associated with TC risk (odds ratio (OR)2,4-DCP =2.28, 95% confidence interval (CI): 1.24-4.18; OR2,4,6-TCP =3.09, 95% CI: 1.66-5.77; ORPCP =3.30, 95% CI: 1.71-6.36, respectively), when CPs were included in the multivariate model and restricted cubic spline function as continuous variables, presenting significant dose-response relationships. Meanwhile, whether in the TC group with tumor diameter > 1 cm or metastatic TC, the changes of 2,4,6 TCP and PCP concentrations were positively correlated with the risk of TC. Our study suggests that higher concentrations of urinary CPs are associated with increased TC risks. Moreover, 2,4,6-TCP and PCP have certain effects on the invasiveness of thyroid cancer. Targeted public health policies should be formulated to reduce the CP pollution. These findings need further in-depth studies to confirm and relevant mechanism also needed to be clarified.

Zeolitic imidazolate framework-8/ fluorinated graphene coated SiO2 composites for pipette tip solid-phase extraction of chlorophenols in environmental and food samples.

In this work, a novel composite adsorbent was successfully prepared by zeolite imidazolate framework-8/fluorinated graphene layer-by-layer covalently bonded on SiO2 microspheres, and followed to be packed into micro pipette tip for extraction of trace chlorophenols prior to their detection by high performance liquid chromatography (HPLC). The morphology and structure of adsorbent material was characterized by field emission scanning electron microscopy with energy dispersive spectrometer, X-ray diffraction, and N2 adsorption. The parameters including the amount of adsorbent, sampling volume, sampling rate, sample pH, and desorption solvent affected the extraction performance was systematically investigated by pipette tip solid-phase extraction (PT-SPE) coupled with HPLC analysis. Under the optimized condition, the linearity of this method ranged from 20 to 2000 ng mL-1 for chlorophenols (CPs) with determination coefficient higher than 0.99. The limit of detection (at a signal-to-noise ratio of 3) were in the range 2-20 ng mL-1 for tap water and black tea drinks, 0.2-2 µg g-1 for honey. The relative recoveries of the CPs from spiked samples ranged from 71.8% to 104.7%, with relative standard deviations less than 6.2%. The filled extraction tube exhibited good stability and reproducibility. The proposed method has been successfully used to detect CPs in water and drinks with satisfactory recoveries.

An eco-friendly low-temperature synthetic approach towards micro-pebble-structured GO@SrTiO3 nanocomposites for the detection of 2,4,6-trichlorophenol in environmental samples.

The low-temperature synthesis of the graphene oxide-wrapped perovskite-type strontium titanate nanocomposites (GO@SrTiO3-NC) is reported for the electrochemical sensing of organochlorine pesticide 2,4,6-trichlorophenol (TCP) detection. The as-prepared GO@SrTiO3 nanocomposites provide a large surface area, excellent conductivity, and active sites, which are more favorable to the catalysis of TCP. The synergistic effect between the GO and the perovskite SrTiO3 results in the extended working range of 0.01 to 1.47 and 1.47 to 434.4 µM with a very low detection limit of 3.21 nM towards TCP detection. Moreover, the prepared sensor possessed good selectivity and long-term stability. Finally, the practical applicability of the sensor was tested in environmental samples of river water and soil, exhibiting adequate recovery values.