A polypyrrole-cotton pad sorbent as micro-solid phase extractor enclosed in tea bag envelope for determination of synthetic antioxidants in non-alcoholic beverage products.

A polypyrrole (PPy)-cotton pad sorbent enclosed in tea bag envelope was developed and used in micro-solid phase extraction (µ-SPE) for the determination of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). After extraction, the extract was qualified and quantified by a gas chromatograph equipped with a flame ionization detector (GC-FID). Parameters influencing this developed method and the efficiency of µ-SPE were studied and optimized. Under the optimal conditions, the developed method provided good linearity in a concentration range of 0.100-100 µg L-1 for BHA and 0.050-50 µg L-1 for BHT, respectively. The limits of detection were 39.27 ± 0.52 ng L-1 for BHA and 16.96 ± 0.17 ng L-1 for BHT. Satisfactory relative recoveries of BHA and BHT were achieved in the range from 86.8 ± 1.9 to 117.1 ± 2.3% with acceptable relative standard deviation (RSD) below 8.1%. Good reproducibility was obtained with RSDs < 3.1%, for n = 6. The developed adsorbent is easy to operate, low cost, eco-friendly, reusable, with high extraction efficiency, and was successfully applied in the simultaneous synthetic antioxidant determination of non-alcoholic beverage samples.

Using Physical Organic Chemistry Knowledge to Predict Unusual Metabolites of Synthetic Phenolic Antioxidants by Cytochrome P450.

Biotransformation, especially by human CYP450 enzymes, plays a crucial role in regulating the toxicity of organic compounds in organisms, but is poorly understood for most emerging pollutants, as their numerous "unusual" biotransformation reactions cannot retrieve examples from the textbooks. Therefore, in order to predict the unknown metabolites with altering toxicological profiles, there is a realistic need to develop efficient methods to reveal the "unusual" metabolic mechanism of emerging pollutants. Combining experimental work with computational predictions has been widely accepted as an effective approach in studying complex metabolic reactions; however, the full quantum chemical computations may not be easily accessible for most environmentalists. Alternatively, this work practiced using the concepts from physical organic chemistry for studying the interrelationships between structure and reactivity of organic molecules, to reveal the "unusual" metabolic mechanism of synthetic phenolic antioxidants catalyzed by CYP450, for which the simple pencil-and-paper and property-computation methods based on physical organic chemistry were performed. The phenol-coupling product of butylated hydroxyanisole (BHA) (based on spin aromatic delocalization) and ipso-addition quinol metabolite of butylated hydroxytoluene (BHT) (based on hyperconjugative effect) were predicted as two "unusual" metabolites, which were further confirmed by our in vitro analysis. We hope this easily handled approach will promote environmentalists to attach importance to physical organic chemistry, with an eye to being able to use the knowledge gained to efficiently predict the fates of substantial unknown synthesized organic compounds in the future.

Prenatal Exposure to Emerging Plasticizers and Synthetic Antioxidants and Their Potency to Cross Human Placenta.

Gestational exposure to environmental chemicals and subsequent permeation through the placental barrier represents potential health risks to both pregnant women and their fetuses. In the present study, we explored prenatal exposure to a suite of 46 emerging plasticizers and synthetic antioxidants (including five transformation products of 2,6-di-tert-butyl-4-hydroxytoluene, BHT) and their potency to cross human placenta based on a total of 109 maternal and cord serum pairs. Most of these chemicals have rarely or never been investigated for prenatal exposure and associated health risks. Eleven of them exhibited detection frequency greater than 50% in maternal blood, including dibutyl fumarate (DBF), 2,6-di-tert-butylphenol (2,4-DtBP), 1,3-diphenylguanidine (DPG), methyl-2-(benzoyl)benzoate (MBB), triethyl citrate (TEC), BHT, and its five metabolites, with a median concentration from 0.05 to 3.1 ng/mL. The transplacental transfer efficiency (TTE) was determined for selected chemicals with valid measurements in more than 10 maternal/cord blood pairs, and the mean TTEs exhibited a large variation (i.e., 0.29-2.14) between chemicals. The determined TTEs for some of the target chemicals were comparable to the predicted values by our previously proposed models developed from molecular descriptors, indicating that their transplacental transfer potency could be largely affected by physicochemical properties and molecular structures. However, additional biological and physiological factors may influence the potency of environmental chemicals to cross human placenta. Overall, our study findings raise concern on human exposure to an increasing list of plastic additives during critical life stages (e.g., pregnancy) and potential health risks.

44-Year Retrospective Analysis of Ultraviolet Absorbents and Industrial Antioxidants in Seabird Eggs from the Canadian Arctic (1975 to 2019).

Ultraviolet (UV) absorbents and industrial antioxidants are contaminants of emerging concern (CECs), but little is known about their distribution in Arctic wildlife, as well as how these contaminants vary over time, across regions, and between species. We used archived egg samples to examine the temporal patterns of 26 UV absorbents and industrial antioxidants in three seabird species (black-legged kittiwakes Rissa tridactyla, thick-billed murres Uria lomvia, northern fulmars Fulmarus glacialis) sampled in Arctic Canada between 1975 and 2019. Various synthetic phenolic antioxidants, aromatic secondary amines, benzotriazole UV stabilizers, and organic UV filters were detected in the seabird eggs. Overall, kittiwakes had higher levels of several UV absorbents and industrial antioxidants. Most target contaminants reached their peak concentrations at different points during the 44-year study period or did not vary significantly over time. None of these contaminant concentrations have increased in recent years. The antioxidant 2-6-di-tert-butyl-4-methylphenol (BHT) was the most frequently detected contaminant in seabird eggs, and its level significantly declined over the course of the study period in kittiwake eggs but did not change in the eggs of murres and fulmars. Future research should examine the effects of these CECs on the health of avian species, the sources, and exposure pathways of these contaminants.

A MWCNTs-COOH/PSS nanocomposite-modified screen-printed electrode for the determination of synthetic phenolic antioxidants by HPLC with amperometric detection.

New sensing platforms based on screen-printed carbon electrodes modified with composites based on polystyrene sulfonate and oxidized multi-walled carbon nanotubes (PSS/MWCNTs-COOH/SPCE) have been used to develop a novel HPLC method with electrochemical detection (ECD) for the determination of the most used synthetic phenolic antioxidants in cosmetics: butylhydroxytoluene (BHT), butylhydroxyanisole (BHA), tert-butylhydroquinone (TBHQ) and propyl gallate (PG). Optimal separation conditions were achieved using methanol: 0.10 mol L-1 acetate solution at pH 6 as mobile phase with a gradient elution program from 60 to 90% of methanol percentage in 15 min. The electrochemical detection was carried out in amperometric mode using the PSS/MWCNTs-COOH/SPCE at + 0.80 V vs. Ag. Under these optimal separation and detection conditions, the limits of detection (LOD) were between 0.11 and 0.25 mg L-1. These LOD values were better, especially for BHT, than those previously published in other HPLC methods. Linear ranges from 0.37 mg L-1, 0.83 mg L-1, 0.69 mg L-1 and 0.56 mg L-1 to 10 mg L-1 were obtained for PG, TBHQ, BHA and BHT, respectively. RSD values equal or lower than 5% and 8% were achieved for repeatability and reproducibility, respectively. The HPLC-ECD method was successfully applied to analyze different cosmetic samples. Recovery values within 83-109% were obtained in the validation studies.

Analysis, occurrence, toxicity and environmental health risks of synthetic phenolic antioxidants: A review.

The continuous improvement of living standards is related to higher requirements for the freshness and taste of food. For example, synthetic phenolic antioxidants (SPAs) are added to fats and fried foods as food additives to minimize the oxidative rancidity of oils and fats. Hence, the global use of SPAs is increasing year by year. Dibutyl hydroxytoluene is one of the widely used SPAs, often in combination with butyl hydroxyanisole or gallate SPAs. The extensive use of these compounds makes them and their transformation products to be widespread in various environmental matrices, including indoor dust, wastewater, river water, sewage sludge, and sediment, as well as human samples, such as nails and urine, at concentrations varying from nanogram per gram (ng/g) to microgram per gram (µg/g). Animal experiments have shown that high-dose SPA exposure is toxic, which may lead to DNA damage and mismatches and the development of cancerous tumors. Since the biosphere shares the same set of genetic codes, humans and animals have many identical or similar feedback mechanisms and information pathways. Therefore, the damage of SPAs to animals may also threaten human health. This review discusses the properties, occurrence, analysis, and environmental health risks of typical SPAs, including butyl hydroxyanisole, dibutyl hydroxytoluene, tert-butylhydroquinone, propyl gallate, octyl gallate, and lauryl gallate, used as food additives. In addition, AO2246, which is used in food packaging bags, is also considered. Future research directions on SPAs and their transformation products (TPs) are identified and discussed.

Synthetic Phenolic Antioxidants: A Review of Environmental Occurrence, Fate, Human Exposure, and Toxicity.

Synthetic phenolic antioxidants (SPAs) are widely used in various industrial and commercial products to retard oxidative reactions and lengthen product shelf life. In recent years, numerous studies have been conducted on the environmental occurrence, human exposure, and toxicity of SPAs. Here, we summarize the current understanding of these issues and provide recommendations for future research directions. SPAs have been detected in various environmental matrices including indoor dust, outdoor air particulates, sea sediment, and river water. Recent studies have also observed the occurrence of SPAs, such as 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4-di-tert-butyl-phenol (DBP), in humans (fat tissues, serum, urine, breast milk, and fingernails). In addition to these parent compounds, some transformation products have also been detected both in the environment and in humans. Human exposure pathways include food intake, dust ingestion, and use of personal care products. For breastfeeding infants, breast milk may be an important exposure pathway. Toxicity studies suggest some SPAs may cause hepatic toxicity, have endocrine disrupting effects, or even be carcinogenic. The toxicity effects of some transformation products are likely worse than those of the parent compound. For example, 2,6-di-tert-butyl-p-benzoquinone (BHT-Q) can cause DNA damage at low concentrations. Future studies should investigate the contamination and environmental behaviors of novel high molecular weight SPAs, toxicity effects of coexposure to several SPAs, and toxicity effects on infants. Future studies should also develop novel SPAs with low toxicity and low migration ability, decreasing the potential for environmental pollution.

In-process prepared deep eutectic solvent based homogeneous liquid-liquid microextraction for the determination of irgaphos 168 and irganox 1010 in polypropylene packed drinks.

In situ synthesis of a deep eutectic solvent and homogeneous liquid-liquid microextraction performed in a narrow bore tube was developed for efficient extraction of irgaphos 168 and irganox 1010 in doogh and water samples packed in polypropylene packages. First, pH of the aqueous sample solutions containing the analytes is adjusted at 9. Then a hydrogen bond acceptor (choline chloride) and a hydrogen bond donor (oleic acid) are dissolved in the solution and vortexed to obtain a homogeneous solution. The solution is filled into a narrow bore tube, in which its bottom was clogged by a septum. Then hydrochloric acid solution is injected into the solution by a syringe. The tube is placed in an ultrasonic bath. During this step, the droplets of choline chloride:oleic acid deep eutectic solvent are produced. The method indicated high enrichment factor (435 for irgaphos 168 and 488 for irganox 1010), low limits of detection (0.03 and 0.09 ng/mL for irgaphos 168 and irganox 1010, respectively) and quantification (0.13 and 0.29 ng/mL for irgaphos 168 and irganox 1010), good recovery (74 and 83% for irgaphos 168 and irganox 1010, respectively), and satisfactory repeatabilities (relative standard deviations ≤12%) can be obtained using the developed method.

Considerations when deriving compound-specific limits for extractables and leachables from pharmaceutical products: Four case studies.

Leachables from pharmaceutical container closure systems are a subset of impurities that present in drug products and may pose a risk to patients or compromise product quality. Extractable studies can identify potential leachables, and extractables and leachables (E&Ls) should be evaluated during development of the impurity control strategy. Currently, there is a lack of specific regulatory guidance on how to risk assess E&Ls; this may lead to inconsistency across the industry. This manuscript is a cross-industry Extractables and Leachables Safety Information Exchange (ELSIE) consortium collaboration and follow-up to Broschard et al. (2016), which aims to provide further clarity and detail on the conduct of E&L risk assessments. Where sufficient data are available, a health-based exposure limit termed Permitted Daily Exposure (PDE) may be calculated and to exemplify this, case studies of four common E&Ls are described herein, namely bisphenol-A, butylated hydroxytoluene, Irgafos® 168, and Irganox® 1010. Relevant discussion points are further explored, including the value of extractable data, how to perform route-to-route extrapolations and considerations around degradation products. By presenting PDEs for common E&L substances, the aim is to encourage consistency and harmony in approaches for deriving compound-specific limits.

Identification of intentionally and non-intentionally added substances in plastic packaging materials and their migration into food products.

Plastic materials are widely used in food packaging applications; however, there is increased concern because of the possible release of undesirable components into foodstuffs. Migration of plastic constituents not only has the potential to affect product quality but also constitutes a risk to consumer health. In order to check the safety of food contact materials, analytical methodologies to identify potential migrants are required. In the first part of this work, a GC/MS screening method was developed for the identification of components from plastic packaging materials including intentionally and "non-intentionally added substances" (NIAS) as potential migrants. In the second part of this study, the presence of seven compounds (bis (2-ethylhexyl) phthalate (DEHP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), butylated hydroxytoluene (BHT), acetyl tributyl citrate (ATBC), benzophenone (BP)) previously identified in packaging materials were investigated in food products (corn and potatoes snacks, cookies, and cakes). For this purpose, a suitable extraction method was developed and quantification was performed using GC-MS. The developed method was validated in terms of linearity, recovery, repeatability, and limits of detection and quantification. The spiked recoveries varied between 82.7 and 116.1%, and relative standard deviation (RSD) was in the range of 2.22-15.9%. The plasticizer ATBC was the most detected compound (94% samples), followed by DEP (65%), DEHP (47%), BP (44%), DBP (35%), DIBP (21%), and BHT (12%). Regarding phthalates, DEP and DEHP were the most frequently detected compounds in concentrations up to 1.44 µg g-1. In some samples, only DBP exceeded the European SML of 0.3 mg kg-1 established in Regulation 10/2011. Graphical abstract Chemical migration from plastic packaging into food.

A stir foam composed of graphene oxide, poly(ethylene glycol) and natural latex for the extraction of preservatives and antioxidant.

A stir foam composed of graphene oxide, poly(ethylene glycol) and natural latex (GO-PEG-NL) was prepared for use in micro-solid phase extraction sorbent of preservative agents and antioxidants from cosmetic products. The extracted analytes were quantified by GC-MS. Under the optimized conditions, the calibration plots are linear in the concentration ranges between 5.0 µg·L-1 to 1.0 mg·L-1 for benzoic acid, of 10.0 µg·L-1 to 1.0 mg·L-1 for 2-methyl-3-isothiazolinone (MI), and between 1.0 µg·L-1 and 1.0 mg·L-1 for both 3-tert-butyl-4-hydroxyanisole (BHA) and 2,6-di-tert-butyl-p-hydroxytoluene (BHT). The LODs are 1.0 µg·L-1 for benzoic acid, 5.0 µg·L-1 for MI and 0.5 µg·L-1 for both BHA and BHT. The stir-foam can be easily prepared, is inexpensive and well reproducible (RSDs <3%, for n = 6). It can be re-used for up to 12 times after which extraction efficiency has dropped to 90%. The method was successfully applied to the determination of preservatives and antioxidants in cosmetic samples. Recoveries from spiked samples ranged between 94.5 ± 2.1% and 99.8 ± 1.8%. Graphical abstract A stir foam was prepared from graphene oxide, poly(ethylene glycol) and natural latex (GO-PEG-NL) and is shown to be a most viable sorbent for the microextraction of trace amounts of preservative agents and antioxidants from cosmetic products.

Synthetic Phenolic Antioxidants and Their Metabolites in Indoor Dust from Homes and Microenvironments.

Synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), are extensively used in food, cosmetic and plastic industries. Nevertheless, limited information is available on human exposures, other than the dietary sources, to SPAs. In this study, occurrence of 9 SPAs and their metabolites/degradation products was determined in 339 indoor dust collected from 12 countries. BHT was found in 99.5% of indoor dust samples from homes and microenvironments at concentrations that ranged from < LOQ to 118 µg/g and 0.10 to 3460 µg/g, respectively. This is the first study to measure BHT metabolites in house dust (0.01-35.1 µg/g) and their concentrations accounted for 9.2-58% of the sum concentrations (∑SPAs). 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO), 2,6-di-tert-butyl-4-(hydroxymethyl)phenol (BHT-OH), 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q) were the major derivatives of BHT found in dust samples. The concentrations of gallic acid esters (gallates) in dust from homes and microenvironments ranged from < LOQ to 18.2 and < LOQ to 684 µg/g, respectively. The concentrations and profiles of SPAs varied among countries and microenvironments. Significantly elevated concentrations of SPAs were found in dust from an e-waste workshop (1530 µg/g). The estimated daily intake (EDI) of BHT via house dust ingestion ranged from 0.40 to 222 ng/kg/d (95th percentile).

Synthetic phenolic antioxidants, including butylated hydroxytoluene (BHT), in resin-based dental sealants.

Resin-based dental sealants (also referred to as pit-and-fissure sealants) have been studied for their contribution to bisphenol A (BPA) exposure in children. Nevertheless, little attention has been paid to the occurrence of other potentially toxic chemicals in dental sealants. In this study, the occurrence of six synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), 2,6-di-tert-butyl-4-(hydroxyethyl)phenol (BHT-OH), 3,5-di-tert-butyl-4-hydroxy-benzaldehyde (BHT-CHO), 2,6-di-tert-butylcyclohexa-2,5-diene-1,4-dione (BHT-Q), 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH) and 2-tert-butyl-4-methoxyphenol (BHA), was examined in 63 dental sealant products purchased from the U.S. market. BHT was found in all dental sealants at median and maximum concentrations of 56.8 and 1020µg/g, respectively. The metabolites of BHT and BHA were detected in 39-67% of samples, at concentration ranges of

Occurrence of synthetic phenolic antioxidants and major metabolites in municipal sewage sludge in China.

Synthetic phenolic antioxidants (SPAs) are one group of widely used additive chemicals, which have not yet had focused attention except for a few compounds such as 2,6-di-tert-butyl-4-methylphenol (BHT). In this study, the occurrence and composition profiles of 12 frequently used SPAs and three BHT metabolites were investigated in fifty-six sludge samples collected from individual wastewater treatment plants in China. Eleven SPAs were positively found in the sludge samples, in which, to our knowledge, eight SPA compounds were identified for the first time in the environment. BHT, 4-tert-octylphenol (4-tOP), and 2,4,6-tri-tert-bultylphenol (AO 246) were the most dominant SPAs in the sludge at mean concentrations of 4.14 µg/g, 374 ng/g, and 98.1 ng/g d.w. (dry weight). Meanwhile, three BHT metabolites, including 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO), 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q), and 2,6-di-tert-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone (BHT-quinol), were also found in most of the samples (>98.2%) with mean concentrations of 141, 562, and 225 ng/g d.w., respectively. The activated sludge system (anaerobic, anoxic, and oxic tanks) of a wastewater treatment plant was further investigated for the removal efficiencies of the SPAs. High removal efficiencies (80.1-89.2%) were found for the six detected SPAs in the aqueous phase, while generation of large proportions of the three BHT metabolites was also observed.

Effect of organic fouling on micro-pollutant rejection in membrane bioreactor treating municipal solid waste landfill leachate.

Effect of membrane fouling on the removal of micro-pollutants from municipal solid waste landfill leachate, i.e. 4-methyl-2,6-di-tert-butylphenol (BHT), bisphenol A (BPA), and bis(2-ethylhexyl)phthalate (DEHP), in membrane bioreactor (MBR) was investigated. Modifications of membrane surface properties were analyzed to determine their relationship with their removals. Membrane fouling was simulated with foulants of different particle sizes on cellulose acetate (CA) microfiltration membrane to investigate the effect of foulant characteristics on BHT, BPA, and DEHP retention in the filtration experiment. The rejection efficiencies of the organic micro-pollutants in the MBR were 82-97% by fouled membrane, and 70-90% by cleaned membrane. The fouled membrane provided higher rejection of micro-pollutants from about 5% for BPA and BHT to 19% for DEHP. These improvements were due to the modification of membrane surface characteristics in terms of surface morphology, and contact angle after membrane fouling. The degree of rejection was found to be dependent upon the characteristics of foulant deposited on CA membrane surface. Increasing foulant particle size and its density shifted the mechanism of micro-pollutant rejection from membrane pore narrowing to pore blocking and cake formation while increasing pollutant adsorption capacity onto the foulant layer.

Importance of sample form and surface temperature for analysis by ambient plasma mass spectrometry (PADI).

Many different types of samples have been analyzed in the literature using plasma-based ambient mass spectrometry sources; however, comprehensive studies of the important parameters for analysis are only just beginning. Here, we investigate the effect of the sample form and surface temperature on the signal intensities in plasma-assisted desorption ionization (PADI). The form of the sample is very important, with powders of all volatilities effectively analyzed. However, for the analysis of thin films at room temperature and using a low plasma power, a vapor pressure of greater than 10(-4) Pa is required to achieve a sufficiently good quality spectrum. Using thermal desorption, we are able to increase the signal intensity of less volatile materials with vapor pressures less than 10(-4) Pa, in thin film form, by between 4 and 7 orders of magnitude. This is achieved by increasing the temperature of the sample up to a maximum of 200 °C. Thermal desorption can also increase the signal intensity for the analysis of powders.

Quantitative analysis of residual butylated hydroxytoluene and butylated hydroxyanisole in Salmo salar, milk, and butter by liquid chromatography-tandem mass spectrometry.

Butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are two commonly used antioxidants with potential health risks associated with excessive intake from multiple sources. Several countries have implemented strict regulations to curb these risks. This study presents a simple LC-MS/MS method for estimating BHT and BHA levels in Salmo salar, butter, and milk. To mitigate any potential interference from the three complex matrices with the ionisation of the target analytes, the method utilised the standard addition approach. The mobile phase used to elute the analytes consisted of 0.1 % formic acid in a mixture of water and acetonitrile (25:75 v/v). Both antioxidants were detected in negative ionisation mode. BHT was identified through single-ion monitoring at a mass-to-charge ratio (m/z) of 219.4, while BHA was detected using multiple-reaction monitoring, with a transition from m/z 164.0 to 149.0. The environmental assessment of the applied procedures verified that the approach is eco-friendly.

[Simultaneous determination of three antioxidants BHA, BHT and TBHQ in food by liquid chromatography and gas chromatography].

OBJECTIVE: To develop a method for determining 3 kinds of antioxidants in food in same time with HPLC and GC. METHODS: Firstly, extracted fat with petroleum ether, then extracted antioxidants with 13 ml methnol, centrifuged, repeated the above procedure twice, combined the extracts, next evaporated to 5 ml, constanted volume to 10 ml, then kepted in freezer (- 1h), lastly, the supernatant injected into high performance liquid chromatography (HPLC) and Gas chromatography (GC) which had been optimized condition. RESULTS: The limits of quantitation for BHA,BHT and TBHQ were 0.002, 0.010 and 0.002g/kg respectively in HPLC, The limits of quantitation for BHA, BHT and TBHQ were 0.003, 0.002 and 0.005 g/kg respectively in GC, The mean recoveries at the two spiked levels were 82.8% - 109.0%. There were no significant difference between HPLC and GC. CONCLUSION: The method can be used to determine the antioxidants in food accurately and sensitively, the comparative results are constant between liquid and gas chromatography.

A green extraction strategy for the detection of antioxidants in food simulants and beverages migrated from plastic packaging materials.

Antioxidants, widely utilized in the food packaging field, have a risk of migrating into foodstuffs and eventually entering the human body. In this work, a novel method was established for green extraction and determination of antioxidants in food simulants migrated from plastic packaging materials. It was found that the antioxidants could be extracted directly from food simulants by in-situ formation of hydrophobic deep eutectic solvents with low toxic medium-chain fatty alcohols. Under the optimal conditions, the limit of detection was 0.15 to 0.25 µg/L, and the limit of quantification was 0.5 to 1.0 µg/L for the antioxidants. The extraction reaches equilibrium in 2 min. Importantly, butylated hydroxytoluene was detected in two types of the surveyed food contact materials. The established method shows high sensitivity, high enrichment factor, and strong anti-interference ability, and can be used for the separation and enrichment of ultra-trace antioxidants in foodstuffs.

Novel macromolecular synthetic phenolic antioxidants in sludge on a national scale in China: Their distribution, potential transformation products, and ecological risk.

To fulfill the growing demand for retarding the oxidation of polymers and minimizing their migration from various products, new macromolecular synthetic phenolic antioxidants (SPAs) have emerged in the market. There is a concern that these SPAs may be released into wastewater streams during their manufacturing and use, eventually ending up in wastewater treatment plants (WWTPs). Nevertheless, information regarding the occurrence of these SPAs in sludge, particularly on a national scale, is scarce. In this study, several macromolecular SPAs and their transformation products (TPs) were investigated in sludge samples from 45 Chinese municipal WWTPs. All 14 analytes were detected in the sludge samples, among which, 12 analytes were first reported in sludge. 2,4,6-tri-tert-butylphenol (AO246) and 2 macromolecular SPAs, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (AO1010) and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (AO1076), were the most dominant SPAs, with geometric mean (GM) concentrations of 547, 212, and 35.2 ng/g dw, respectively. Two TPs, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoic acid (fenozan) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH), were found in some sludge samples (48.9-71.1 %) with GM of 45.5 and 12.8 ng/g dw, respectively. By using LC-Q-TOF-MS/MS analysis, we tentatively identified previously unknown TPs of 10 macromolecular SPAs in sludge. This suggests that there are still unclear mechanisms modulating the transformation of these SPAs, which underscores the complexity of their fate. Additionally, using the freshwater photobacteria Vibrio qinghaiensis sp.-Q67 (Q67) as model organism, the acute and chronic EC50 of the 14 analytes were assessed for ecological risk assessment. By considering toxicity data obtained from algae, daphnia, and fish collected or predicted from various databases, we found that these analytes, including their mixture at low detected concentrations, pose risks to aquatic systems that should not be disregarded. Overall, the current study provides a comprehensive overview of novel SPAs and their TPs in sludge, offering valuable insights for investigating their environmental behavior, fate, and risks.