Determination of endocrine disrupting chemicals in human nails using an alkaline digestion prior to ultra-high performance liquid chromatography–tandem mass spectrometry

Bisphenols in indoor dust: A comprehensive review of global distribution, exposure risks, transformation, and biomonitoring

Bisphenols (BPs) are pervasive environmental contaminants extensively found in indoor environments worldwide. Despite their ubiquitous presence and potential health risks, there remains a notable gap in the comprehensive reviews focusing on BPs in indoor dust. Existing literature often addresses specific aspects such as exposure pathways, transformation products, or biomonitoring techniques, but lacks a consolidated, in-depth review encompassing all these facets. This review provides a comprehensive overview of the global distribution of BPs, emphasizing their prevalence in diverse indoor settings ranging from households and workplaces to public areas. Variations in BP concentrations across these environments are explored, influenced by factors such as industrial activities, consumer product usage patterns, and geographical location. Exposure assessments highlight ingestion, inhalation, and dermal contact as primary pathways for BP exposure, with ingestion being particularly significant for vulnerable groups such as infants and young children. Studies consistently reveal higher concentrations of BPs in urban indoor dust compared to rural settings, reflecting the impact of urbanization and intensive consumer practices. Moreover, BPs from mobile sources like vehicles contribute significantly to overall human exposure, further complicating exposure assessments. The review also delves into the transformation of BPs within indoor environments, emphasizing the diverse roles of physical, chemical, and biological processes in generating various transformation products (TPs). These TPs can exhibit heightened toxicity compared to their parent compounds, necessitating deeper investigations into their environmental fate and potential health implications. Critical examination of biomonitoring techniques for BPs and their metabolites underscores the importance of non-invasive sampling methods, offering ethical advantages and practicality in assessing human exposure levels. The emerging use of bioindicators, encompassing plants, animals, and innovative approaches like spider webs, presents promising avenues for effectively monitoring environmental contamination.

Development of a method to evaluate the effects of external environments on drug stability in nails using micro-segmental analysis

Nails can be used as an alternative to hair for examining past drug use. However, daily hand-and-nail care can eliminate the internal drugs. Therefore, we developed an evaluation method to examine the effects of the external environment on drug stability in nails using micro-segmental analysis. First, reference nails containing drugs were prepared by collecting fingernails from participants who had consumed hay-fever medicines continuously for 4 months. Next, the entire free edge of a reference nail was cut into halves at the centerline; one side was stored as an untreated block, and the other was treated with various hand/nail care products. Both nail blocks were washed and segmented at 0.5-mm intervals in the width direction. Each segment in the extraction solution was crushed with stainless-steel beads, sonicated, and soaked in the solution for 24 h. The analytes in extracts were quantified by LC-MS/MS, and the drug concentrations between the treated and untreated blocks were compared. The drug concentrations decreased slightly in nails treated with manicure and gel-nail products. The analytes in nails tended to be lower in water-rich products such as hand soap and hand cream than in oil-rich products such as nailcare oil and acetone-free remover. The developed method using micro-segmental analysis enabled the evaluation of the effects of various hand/nail care products on drug stability in a limited number of nails. This would also be useful for examining the effects of severe environments on drugs in nails collected from cases of unnatural death.

Methodology for Biological Sample Collection, Processing, and Storage in the Newcastle 1000 Pregnancy Cohort: Protocol for a Longitudinal, Prospective Population-Based Study in Australia

BACKGROUND

Research in the developmental origins of health and disease provides compelling evidence that adverse events during the first 1000 days of life from conception can impact life course health. Despite many decades of research, we still lack a complete understanding of the mechanisms underlying some of these associations. The Newcastle 1000 Study (NEW1000) is a comprehensive, prospective population-based pregnancy cohort study based in Newcastle, New South Wales, Australia, that will recruit pregnant women and their partners at 11-14 weeks' gestation, with assessments at 20, 28, and 36 weeks; birth; 6 weeks; and 6 months, in order to provide detailed data about the first 1000 days of life to investigate the developmental origins of noncommunicable diseases.

OBJECTIVE

The study aims to provide a longitudinal multisystem approach to phenotyping, supported by robust clinical data and collection of biological samples in NEW1000.

METHODS

This manuscript describes in detail the large variety of samples collected in the study and the method of collection, storage, and utility of the samples in the biobank, with a particular focus on incorporation of the samples into emerging and novel large-scale "-omics" platforms, including the genome, microbiome, epigenome, transcriptome, fragmentome, metabolome, proteome, exposome, and cell-free DNA and RNA. Specifically, this manuscript details the methods used to collect, process, and store biological samples, including maternal, paternal, and fetal blood, microbiome (stool, skin, vaginal, oral), urine, saliva, hair, toenail, placenta, colostrum, and breastmilk.

RESULTS

Recruitment for the study began in March 2021. As of July 2024, 1040 women and 684 partners were enrolled, with 922 infants born. The NEW1000 biobank contains 24,357 plasma aliquots from ethylenediaminetetraacetic acid (EDTA) tubes, 5284 buffy coat aliquots, 4000 plasma aliquots from lithium heparin tubes, 15,884 blood serum aliquots, 2977 PAX RNA tubes, 26,595 urine sample aliquots, 2280 fecal swabs, 17,687 microbiome swabs, 2356 saliva sample aliquots, 1195 breastmilk sample aliquots, 4007 placental tissue aliquots, 2680 hair samples, and 2193 nail samples.

CONCLUSIONS

NEW1000 will generate a multigenerational, deeply phenotyped cohort with a comprehensive biobank of samples relevant to a large variety of analyses, including multiple -omics platforms.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/63562.

Analytical methods and biomonitoring results in hair for the assessment of exposure to endocrine-disrupting chemicals: A literature review

Endocrine-disrupting chemicals (EDC) are compounds that alter functions of the endocrine system due to their ability to mimic or antagonize endogenous hormones, or that alter their synthesis and metabolism, causing adverse health effects. Human biomonitoring (HBM) is a reliable method to assess human exposure to chemicals through measurement in human body fluids and tissues. It identifies new sources of exposure and determines their distribution, thereby enabling detection of the most exposed populations. Blood and urine are commonly used for HBM of EDC, but their interest is limited for compounds presenting short half-lives. Hair appears as an interesting alternative insofar as it provides a large exposure window. For the present study, we evaluated the relevance of hair in determining EDC exposure. With this in mind, we undertook a literature review focusing on the bioanalytical aspects and performances of methods developed to determine EDC in hair. The literature review was performed through methodical bibliographical research. Relevant articles were identified using two scientific databases: PubMed and Web of Science, with search equations built from a combination of keywords, MeSH terms and Boolean operators. The search strategy identified 2949 articles. After duplicates were removed, and following title, abstract, and full-text screenings, only 31 were included for qualitative synthesis. Hair collection was mainly performed in the back of the head and preparation involved two processes: cutting into small pieces or grounding to powder. The off-line LC-MS/MS method remains the main technique used to assess EDC through hair. Differences regarding the validation of analytical methods and interpretation of HBM results were highlighted, suggesting a need for international harmonisation to obtain reliable and comparable results. External contamination of hair was identified as a main limitation in the interpretation of results, highlighting the need to better understand EDC transfers through hair and to develop relevant hair decontamination processes.

Levels of Bisphenol A and its analogs in nails, saliva, and urine of children: a case control study

Introduction

A growing number of studies link the increase in overweight/obesity worldwide to exposure to certain environmental chemical pollutants that display obesogenic activity (obesogens). Since exposure to obesogens during the first stages of life has been shown to have a more intense and pronounced effect at lower doses, it is imperative to study their possible effects in childhood. The objective here was to study the association of Bisphenol A (BPA) and 11 BPA analogs in children, using three biological matrices (nails, saliva and urine), and overweight and obesity (n = 160).

Methods

In this case-control study, 59 overweight/obese children and 101 controls were included. The measuring of Bisphenols in the matrices was carried out by ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-MS/MS). Logistic regression was used to study the association between overweight/obesity and Bisphenol exposure.

Results

The results suggested that BPF in nails is associated with overweight/ obesity in children (OR:4.87; p = 0.020). In saliva, however, the highest detected concentrations of BPAF presented an inverse association (OR: 0.06; p = 0.010) with overweight/obesity. No associations of statistical significance were detected between exposure to BPA or its other analogs and overweight/obesity in any of the biological matrices.

Analytical method for the determination of usually prescribed antibiotics in human nails using UHPLC-MS/MS. Comparison of the efficiency of two extraction techniques

Antibiotics are a group of drugs used for the treatment of bacterial diseases. They are used in both human and veterinary medicine and, although they are not permitted, they are sometimes used as growth promoters. The present research compares two extraction techniques: ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) in order to evaluate their efficiency in the determination of 17 usually prescribed antibiotics in human nails. The extraction parameters were optimized using multivariate techniques. Once both techniques were compared, MAE was selected as optimal due to its greater experimental practicability together with the better extraction efficiencies it provides. Target analytes were detected and quantified by ultra-high performance liquid chromatography with tandem mass spectrometry detection (UHPLC-MS/MS). The run time was 20 min. The methodology was then successfully validated, obtaining acceptable analytical parameters according to the guide used. Limits of detection were between 0.3 and 3 ng g^-1 and limits of quantification were in the range from 1.0 to 4.0 ng g^-1. Recovery percentages ranged from 87.5% to 114.2%, and precision (in terms of standard deviation) was less than 15% in all cases. Finally, the optimized method was applied to nails taken from 10 volunteers and the results revealed the presence of one or more antibiotics in all the samples examined. The most commonly found antibiotic was sulfamethoxazole, followed by danofloxacin and levofloxacin. The results demonstrated, on the one hand, the presence of these compounds in the human body and, on the other hand, the suitability of nails as a non-invasive biomarker of exposure.

Human nails as a valuable noninvasive alternative for estimating exposure to parabens

Exposure of human to parabens (commonly used preservatives) is inevitable due to their extensively applied in numerous consumer products. Thus, a reliable noninvasive matrix reflecting long-term exposure to parabens is essential for human biomonitoring study. Human nails are potentially a valuable alternative for measuring intergrated exposure to parabens. In this work, we collected 100 paired nail and urine samples from university students in Nanjing, China, and measured simultaneously for six parent parabens and four metabolites. Methylparaben (MeP), ethylparaben (EtP), and propylparaben (PrP) were three predominant paraben analogue in both matrices, with the median concentrations being 12.9, 0.753, and 3.42 ng/mL in urine, and 1540, 154, and 961 ng/g in nail, respectively, while 4-hydroxybenzoic acid (4-HB) and 3,4-dihydroxybenzoic acid (3,4-DHB) were the most abundant metabolites (median values of 143 and 35.9 ng/mL, respectively) in urine. Gender-related analysis suggested that females exposed to more higher parabens than males. Significantly positive correlations were found between levels of MeP, PrP, EtP, and OH-MeP (r = 0.54-0.62, p < 0.01) in paired urine and nail samples. Our result here suggests that human nails, as an emerging biospecimen, are a potentially valuable biological matrix to evaluate human long-term exposure to parabens.

Presence of Parabens in Different Children Biological Matrices and Its Relationship with Body Mass Index

Parabens have been accepted almost worldwide as preservatives by the cosmetic, food, and pharmaceutical industries. Since epidemiological evidence of the obesogenic activity of parabens is weak, the aim of this study was to investigate the association between parabens exposure and childhood obesity. Four parabens (methylparaben/MetPB, ethylparaben/EthPB, propylparaben/PropPB, and butylparaben/ButPB) were measured in 160 children's bodies between 6 and 12 years of age. Parabens measurements were performed with ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Logistic regression was used to evaluate risk factors for elevated body weight associated with paraben exposure. No significant relation was detected between children's body weight and the presence of parabens in the samples. This study confirmed the omnipresence of parabens in children's bodies. Our results could be a basis for future research about the effect of parabens on childhood body weight using nails as a biomarker due to the ease of its collection and its non-invasive character.

Presence of parabens in children's faeces. Optimization and validation of a new analytical method based on the use of ultrasound-assisted extraction and liquid chromatography-tandem mass spectrometry

Due to their antimicrobial properties, parabens are a family of synthetic chemical compounds widely used as preservative additives in food and cosmetics. For this reason, humans are highly exposed to them. These substances are capable of altering the proper functioning of the endocrine system and are classified as endocrine disrupting chemicals (EDCs). Traditionally, urine has been the typical matrix studied as an excretion route. However, faeces contain valuable information. In the present study, the presence of methyl-, ethyl-, isopropyl-, propyl-, isobutyl-, butyl- and phenylparaben in stool samples from children has been evaluated. A new analytical method has been optimised and validated. The method is based on the use of ultrasound-assisted extraction followed by clean-up of the extracts by dispersive solid phase extraction dSPE). Parabens were analysed by ultrahigh performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The matrix effect was evaluated and a significant effect was observed for all analytes. Therefore, calibration and validation were performed by addition of different concentrations of analytes to faecal blanks. The coefficient of determination (%R²) for calibration curves was higher than 98.9% in all cases. The limits of detection and quantification were between 0.2 and 0.4 and 0.6-1.0 ng g^-1 respectively. The recovery for accuracy assessment had values between 89.0% and 112.7% with an RSD of less than 15% in all cases. The method was successfully applied to 14 samples from children volunteers, 100% of which showed contamination by at least one of the analysed compounds.

Evaluation of acetamiprid and azoxystrobin residues and their hormonal disrupting effects on male rats using liquid chromatography-tandem mass spectrometry

Endocrine-disrupting compounds as pesticides affect the hormonal balance, and this can result in several diseases. Therefore, the analysis of representative hormones with acetamiprid (AC) and azoxystrobin (AZ) was a good strategy for the investigation of the endocrine-disrupting activity of pesticides. Hence, a sensitive and rapid analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The method was validated for the analysis of AC, AZ, estriol, estrone, progesterone, and testosterone in the serum, testis, and liver of rats. The correlation between the residues of pesticides and the disturbance of the endocrine system was evaluated. The different mass parameters, mobile phase types, analytical columns, injection volumes, and extraction solvents were compared to get the lowest limit of detection of the studied compounds. The detection limits of AC, AZ, estriol, estrone, progesterone, and testosterone were 0.05, 0.05, 1.0, 10, and 1.0 ng/ml, respectively. The method developed was applied to evaluate the changes in these hormones induced by the duration of exposure to AC and AZ in rat testis and serum. The hormones level in rat serum and testis had a significant decrease as they were oral gavage treated with different high concentrations of studied pesticides. Both pesticides were distributed in the body of rats by the multi-compartment model (liver, testis, and serum).

Evaluation of three sorbent-phase extraction techniques based on hyper-crosslinked polymer for the extraction of five endocrine disrupters in water

A series of low-cost hyper-crosslinked polymers were prepared by an easy one-step Friedel-Crafts reaction. The synthesized hyper-crosslinked polymers exhibited remarkably porous structure, large surface area, and hydroxyl groups, which can be employed as an ideal adsorbent material for novel sorbent-phase extraction techniques. Based on this, using hyper-crosslinked polymers as sorbent and coating, three novel extraction methods, including micro-solid-phase extraction, dispersive solid-phase extraction, and solid-phase microextraction, were explored and evaluated for simultaneous measurement of five endocrine-disrupting compounds (triclosan and bisphenol A, tetrabromobisphenol A, tetrabromobisphenol A bisallylether, and tetrabromobisphenol A bis(2,3-dibromopropyl ether)) in environment water prior to high-performance liquid chromatography-ultraviolet. The influence of experimental parameters on three extraction techniques such as extraction time, the amount of hyper-crosslinked polymers, extraction temperature, ionic strength, and desorption conditions were optimized. Three previously mentioned methods provided limits of detection ranging from 0.01 to 0.05 μg/L, and high recoveries (85-99%) with relative standard deviations of 1.7-5.6%. This study presented the merits and disadvantages of three proposed extraction methods and their potential for effective monitoring of hazardous pollutants in real water samples.

Dietary exposure to parabens and body mass index in an adolescent Spanish population

Parabens are alkyl esters of p-hydroxybenzoic acid which are extensively used in cosmetics, pharmaceuticals and foodstuffs due to their antimicrobial properties. The most commonly used parabens are methyl-(MeP), ethyl-(EtP), propyl-(PrP) and butyl-(BuP) paraben. Most human exposure to parabens is achieved through the consumption of food or pharmaceutical products and the use of personal care products. However, studies on dietary parabens exposure and the associated factors are very scarce. The main aim of the present study was to explore factors associated with dietary exposure to parabens in Spanish adolescents according to gender. Dietary data and anthropometric measures were collected from 585 adolescents (53.4% boys) aged 12-16 years. Parabens exposure through diet was assessed using a food frequency questionnaire with food products providing more than 95% of energy and macronutrient intake being included in analysis. Stepwise regression was used to identify the foods that most contributed to parabens intake. Logistic regression was used to evaluate factors predicting higher dietary exposure to parabens. The main contributors to dietary MeP, EtP, PrP and BuP exposure in adolescent boys were eggs (41.9%), canned tuna (46.4%), bakery and baked goods products (57.3%) and pineapple (61.1%). In adolescent girls, the main contributors were apples and pears (35.3%), canned tuna (42.1%), bakery and baked goods products (55.1%) and olives (62.1%). Overweight/obese girls were more likely to belong to the highest tertile of overall parabens intake (odds ratio [OR]: 3.32; 95% confidence interval [95% CI]: 1.21-9.15) and MeP (OR: 3.05; 95% CI: 1.14-8.12) than those with a body mass index lower than 25 kg/m². These findings suggest a positive association between dietary exposure to parabens and overweight/obesity in adolescent girls.

Determination of ultraviolet filters in human nails using an acid sample digestion followed by ultra-high performance liquid chromatography-mass spectrometry analysis

Ultraviolet filters (UV-filters) are specific chemicals that absorb and reflect UVA and UVB radiation from the sun. They are regularly used in sunscreens and in other personal care products (PCPs), and in products like plastics, adhesives, toys, or furniture finishes. This work develops and validates a new method to determine concentrations of UV-filters (BP-1, BP-2, BP-3, BP-6, BP-8, 4-OH-BP, THB, AVB) in human nail samples. Nails are easily available and are considered to be suitable indicators of cumulative and continued exposure to harmful chemicals. The treatment of nail samples includes microwave assisted digestion/extraction (MAE) in a methanolic solution of o-phosphoric acid (0.05 mol L^-1) followed by analyte determination using ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) in multiple reaction monitoring mode. The analytes were separated in less than 10 min. The digestion procedure was optimized using multivariate techniques. Matrix-matched calibration with a pig hoof matrix was used for validating the method. A study of accuracy with spiked blank samples was also conducted. The calculated detection limits varied between 0.2 and 1.5 ng g^-1, and quantification limits between 1.0 and 5.0 ng g^-1. The trueness of the method was an estimation of the recovery, which was between 90.2% and 112.2%; with an estimated precision (relative standard deviation, % RSD) lower than 12.3% for all UV-filters. Nail samples were obtained from 22 volunteers (male and female). The results showed that BP-1 and BP-3 mainly bioaccumulate in human nails.

Presence of Parabens and Bisphenols in Food Commonly Consumed in Spain

Given the widespread use of bisphenols and parabens in consumer products, the assessment of their intake is crucial and represents the first step towards the assessment of the potential risks that these compounds may pose to human health. In the present study, a total of 98 samples of food items commonly consumed by the Spanish population were collected from different national supermarkets and grocery stores for the determination of parabens and bisphenols. Our analysis demonstrated that 56 of the 98 food samples contained detectable levels of parabens with limits of quantification (LOQ) between 0.4 and 0.9 ng g-1. The total concentration of parabens (sum of four parabens: ∑parabens) ranged from below the LOQ to 281.7 ng g-1, with a mean value of 73.86 ng g-1. A total of 52% of the samples showed detectable concentrations of bisphenols. Bisphenol A (BPA) was the most frequently detected bisphenol in the food samples analysed, followed by bisphenol S (BPS) and bisphenol E (BPE). Bisphenol AF (BPAF), bisphenol B (BPB) and bisphenol P (BPP) were not found in any of the analysed samples. LOQ for these bisphenols were between 0.4 and 4.0 ng g-1.

A fast-multiclass method for the determination of 21 endocrine disruptors in human urine by using vortex-assisted dispersive liquid-liquid microextraction (VADLLME) and LC-MS/MS

Simplicity, speed, and reduced cost are essential demands for routine analysis in human biomonitoring studies. Moreover, the availability of higher volumes of human specimens is becoming more restrictive due to ethical controls and to the costs associated with sample transportation and storage. Thus, analytical methods requiring much lower sample volumes associated with simultaneous detection capability (multiclass analysis) are with a very high claim. In this sense, the present approach aimed at the development of a method for preconcentration and simultaneous determination of four classes of endocrine disruptors (seven bisphenols, seven parabens, five benzophenones, and two antimicrobials) in the urine. The approach is based on vortex-assisted dispersive liquid-liquid microextraction (VADLLME) and high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). After optimization of the significant parameters of VADLLME extraction, the proposed procedure showed to be simple, fast, sensitive, requiring only 1.0 mL of urine, 400 μL of organic solvents with a total stirring time of 20 s. Moreover, a variation of inter-day and between-day runs were lower than 10.0% and 11.0%, respectively. Finally, the proposed method was successfully applied to the analysis of 50 urine samples of Brazilian pregnant women to establish reference ranges.

Analysis of methylparaben in cosmetics based on a chemiluminescence H2 O2 -NaIO4 -CNQDs system

In this article, a simple, effective chemiluminescence (CL) method for the detection of methylparaben (MP) in cosmetic samples was developed based on an IO₄ ^- -H₂ O₂ -carbon nitrogen quantum dots (CNQDs) system without a separation process. The results indicated that the redox reaction between periodate and hydrogen peroxide released hydroxide radicals and superoxide radical anions in the presence of bicarbonate. These two radicals were responsible for the formation of excited luminophor CNQD* with a maximum wavelength at 480 nm. Due to the competitive reaction with hydroxide radicals, CL intensity was markedly diminished in the presence of MP. The relative standard deviation in the intraday assay was below 5.5% (n = 9), and the detection limit was as low as 0.50 μmol/L. The proposed method allowed for the successful, selective determination of MP in cosmetics.