Multi-class determination of intracellular and extracellular cyanotoxins in freshwater samples by ultra-high performance liquid chromatography coupled to high resolution mass spectrometry.

In the past decades, the intensity and duration of cyanobacterial blooms are increasing due to anthropogenic factors. These phenomena worry drinking water companies and water managers because cyanobacteria produce a diverse range of cyanotoxins, which can cause liver, digestive and neurological diseases. The main exposure routes for humans are the consumption of drinking water that has not been effectively treated and the recreational use of polluted waters. For risk assessment and to conduct studies on large-scale occurrence, the development of reliable but simple, sensitive and cost-effective analytical approaches able to cover a wide range of cyanotoxins is essential. Additionally, the determination of intracellular and extracellular toxins separately is advantageous for risk management. To the best of our knowledge, this is the first time that a method for the multi-class determination of cyanotoxins in fresh water, which is able to separately report intra- and extracellular toxins, meet the criteria of simplicity (not requiring multiple sample preparation procedures or time-consuming steps) and it is based on highly specific high resolution mass spectrometry (potential for wide screening and retrospective analysis). Matrix effects, trueness and precision met general validation criteria for a group of nine cyanotoxins, including anatoxins, cylindrospermopsin and microcystins. Considering a 50 mL sample, the method quantification limits were within the range of 8-45 ng L-1 and 25-129 ng L-1 for intra- and extracellular cyanotoxins, respectively. Anatoxin-a, cylindrospermopsin and some microcystins were found in three out of four Dutch lakes included in the study, at concentrations up to 52 µg L-1.

Saliva-induced coacervation of inverted aggregates of hexanol for simplifying human biomonitoring: Application to the determination of free bisphenols.

Saliva is progressively becoming a useful alternative to urine and blood to assess human exposure to toxics in biomonitoring campaigns, because of its easy and stress-free collection by unskilled personnel. This evaluation is highly challenging owing to the large number of compounds and individuals involved. In this article, we propose a new strategy to simplify sample treatment in the human biomonitoring of toxics in saliva. It is based on the in situ formation of supramolecular solvents (SUPRASs) in the sample. For this purpose, SUPRASs were produced in colloidal suspensions of aggregates of hexanol in THF under the addition of saliva, which played the dual role of inductor of the self-assembly process leading to SUPRAS formation and the sample to be analysed. The SUPRAS formation region was delimited from the phase diagram constructed for the ternary mixture saliva/hexanol/THF. An equation was derived for predicting the volume of SUPRASs produced as a function of the proportion of their components. The new strategy was explored for simplifying sample treatment in the biomonitoring of thirteen free bisphenol analogues and derivatives by liquid chromatography tandem mass spectrometry. Absolute recoveries for bisphenols were in the range 95-105.6%, the method was interference free (signal suppression/enhancement was between 93 and 106%), and the repeatability and within laboratory reproducibility were in the intervals 0.6-10% and 2-16%, respectively. The proposed method was fully validated and it was applied to the determination of the target bisphenols in saliva from 13 volunteers. Free bisphenol A was found in all samples (0.057-0.8 µg L-1), and bisphenol F, bisphenol S and bisphenol AF were found with a frequency of detection of 46%, 62% and 8%, respectively. So, saliva can be a suitable biological sample for studying human exposure to bisphenols. To the best of our knowledge, this is the first report dealing with the use of saliva for biomonitoring human exposure to bisphenols.

Presence of diphenyl phosphate and aryl-phosphate flame retardants in indoor dust from different microenvironments in Spain and the Netherlands and estimation of human exposure.

Phosphate flame retardants (PFRs) are ubiquitous chemicals in the indoor environment. Diphenyl phosphate (DPHP) is a major metabolite and a common biomarker of aryl-PFRs. Since it is used as a chemical additive and it is a common impurity of aryl-PFRs as well as a degradation product, its presence in indoor dust as an additional source of exposure should not be easily ruled out. In this study, DPHP (and TPHP) are measured in indoor dust in samples collected in Spain and in the Netherlands (n=80). Additionally, the presence of other emerging aryl-PFRs was monitored by target screening. TPHP and DPHP were present in all samples in the ranges 169-142,459ng/g and 106-79,661ng/g, respectively. DPHP concentrations were strongly correlated to the TPHP levels (r=0.90, p<0.01), suggesting that DPHP could be present as degradation product of TPHP or other aryl-PFRs. Estimated exposures for adults and toddlers in Spain to TPHP and DPHP via dust ingestion (country for which the number of samples was higher) were much lower than the estimated reference dose (US EPA) for TPHP. However, other routes of exposure may contribute to the overall internal exposure (diet, dermal contact with dust/consumer products and inhalation of indoor air). The estimated urinary DPHP levels for adults and toddlers in Spain (0.002-0.032ng/mL) as a result of dust ingestion were low in comparison with the reported levels, indicating a low contribution of this source of contamination to the overall DPHP exposure. Other aryl-PFRs, namely cresyl diphenyl phosphate (CDP), resorcinol bis(diphenyl phosphate) (RDP), 2-ethylhexyl diphenyl phosphate (EDPHP), isodecyl diphenyl phosphate (IDP) and bisphenol A bis(diphenyl phosphate) (BDP), were all detected in indoor dust, however, with lower frequency.