Societal and environmental concern due to frequent reports of microplastics in fish stomachs raised as they may accumulate along the trophic chain. The request for analysing microplastics in fish ...stresses two major analytical issues: sample treatment and final characterization. The, so far, workhorse for chemical characterization is infrared spectroscopy which is time-consuming. Here, a quantum cascade laser-based device is used to accelerate the characterization stage. Its novelty poses new challenges for sample processing and particle handling because the unknown particles must be transferred to a reflective slide. In this study, three sample digestion protocols (alkaline-oxidative with H2O2, and alkaline-oxidative with NaClO and enzymatic-oxidative) and three different procedures to transfer the filter cake to reflective slides are compared. A simplified enzymatic-oxidative digestion (validated through an interlaboratory exercise) combined with a Syncore® automatic evaporation system and a Laser Direct Infrared Imaging (LDIR) device is proposed first time as a reliable and relatively fast method to treat gastrointestinal tracts of fish. Analytical recoveries were studied using samples of Scomber scombrus and they were ca. 100% for big –i.e., >500 μm- and ca. 90% for medium –i.e., 200–300 μm- particles and ca. 75% for 10 μm thick fibres.
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•Three digestion methods for gastrointestinal tract digestion were studied.•Enzymatic-oxidative digestion plus H2O2 bleaching yielded excellent recoveries.•Three forms of particle transfer to LDIR reflective slides were studied.•Manual pickup and total filtrate transfer led ≥90% recoveries for ≥10 μm.•The method allowed satisfactory recoveries of fibres, ca. 75%.
Infrared spectrometry (IR) became a workhorse to characterize microplastics (MPs) worldwide. However, reports on the experimental conditions to measure them decreased alarmingly. As complete, ...relevant information on the instrumental setup determining IR spectra is crucial for scientific reproducibility, ca. 50% of the papers that reported FTIR to measure MPs were evaluated and it was found that most studies cannot be replicated due to missing experimental details. To ameliorate this, the most critical parameters influencing IR spectra are depicted, their impact when matching a spectrum against databases exemplified, and, following efforts from other scientific fields, a minimum information for publication of IR-related data on MPs characterization (MIPIR-MP) is proposed, along with a brief, simple paragraph to resume the most critical information to be reported. This can be used to improve the worrying figures that point out to a reproducibility crisis in the field, as disclosed by the survey.
•Studies on microplastics lack information on IR measurement setup parameters•Around 25% of published papers do not offer useful instrumental information•A lack of understanding of basic IR parameters might affect polymer identifications•The quality of reported data on microplastics is compromised•A paragraph is proposed to minimize the lack of IR instrumental information
Currently, gas chromatography is the most common analytical technique for natural gas (NG) analysis as it offers very precise results, with very low limits of detection and quantification. However, ...it has several drawbacks, such as low turnaround times and high cost per analysis, as well as difficulties for on-line implementation. With NG applications rising, mostly thanks to its reduced gaseous emissions in comparison with other fossil fuels, the necessity for more versatile, fast, and economic analytical methods has augmented. This work summarizes the latest advances to determine the composition and physico-chemical properties of regasified liquid natural gas, focusing on infrared spectroscopy-based techniques, as well as on data processing (chemometric techniques), necessary to obtain adequate predictions of NG properties.
Atmospheric particulate matter (PM) has been related to numerous adverse health effects in humans. Nowadays, it is believed that one of the possible mechanisms of toxicity could be the oxidative ...stress, which involves the development of reactive oxygen species (ROS). Different assays have been proposed to characterize oxidative stress, such as dithiothreitol (DTT) and ascorbic acid (AA) acellular assays (OP
DTT
and OP
AA
), as a metric more relevant than PM mass measurement for PM toxicity. This study evaluates the OP of the bioaccessible fraction of 65 PM
10
samples collected at an Atlantic Coastal European urban site using DTT and AA assays. A physiologically based extraction (PBET) using Gamble’s solution (GS) as a simulated lung fluid (SLF) was used for the assessment of the bioaccessible fraction of PM
10
. The use of the bioaccessible fraction, instead of the fraction assessed using conventional phosphate buffer and ultrasounds assisted extraction (UAE), was compared for OP assessment. Correlations between OP
DTT
and OP
AA
, as well as total and bioaccessible concentrations of polycyclic aromatic hydrocarbons (PAHs) and metal(oid)s, were investigated to explore the association between those compounds and OP. A correlation was found between both OP (OP
DTT
and OP
AA
) and total and bioaccessible concentrations of PAHs and several metal(oid)s such as As, Bi, Cd, Cu, Ni, and V. Additionally, OP
DTT
was found to be related to the level of K
+
.
► Fifty-three emerging pollutants measured in sewage, surface and drinking water. ► Nineteen compounds detected in sewage at median values higher than 0.1μgL. ► Eleven of them not properly eliminated ...and still higher than 0.1μgL−1 in effluent. ► Pharmaceuticals, UV filters and organoP flame retardants prevail in surface water. ► BP-4, TnBP, TCEP and several organoP diesters found in drinking water at 10–100ngL−1.
A monitoring programme was carried out on wastewater, surface and drinking water on the NW area of Spain during the four seasons of a year period (November 2007–September 2008). This study covered a series of emerging pollutants of different classes, including pharmaceuticals, neutral and acidic organophosphorus flame retardant/plasticizers (OPs), triclosan, phenoxy-herbicides, insect repellents and UV filters. From the total set of 53 compounds, 19 were found in raw wastewater with median concentrations higher than 0.1μgL−1. Among them, salicylic acid, ibuprofen and the UV filter benzophenone-4 (BP-4) were the most concentrated, exceeding the 1μgL−1 median value. Subsequently, 11 of these contaminants are not efficiently enough removed in the small WWTPs tested and their median concentrations in effluents still surpassed the 0.1μgL−1, so that they can spread through surface water. These chemicals are the pharmaceuticals naproxen, diclofenac and atenolol; the OPs tri(2-chloroethyl) phosphate (TCEP), tri(chloropropyl) phosphate (TCPP), tri-n-butyl phosphate (TnBP), diphenyl phosphate (DPhP) and diethylhexyl phosphate (DEHP); and the sulphonate UV filters BP-4 and 2-phenylbenzimidazole-5-sulphonic acid (PBSA). These OPs were then the dominant emerging pollutants occurring in surface and drinking water, where they are detected in the 20–200ngL−1 range. Pharmaceuticals and UV filters are typically below the 10ngL−1 level. Finally, herbicides were only detected in the last sampling campaign under the 100ngL−1 drinking water European Union limit.
► Development of a method for determination of non-steroidal anti-inflammatory drugs. ► Fully automated method including derivatization and gas chromatography–mass spectrometry. ► Analyte enrichment ...by microextraction by packed sorbent (MEPS).
The present work describes the development and validation of a method for the determination of five non-steroidal anti-inflammatory drugs (NSAIDs: clofibric acid, ibuprofen, naproxen, diclofenac and ketoprofen) in water samples. The fully automated method includes
in situ aqueous derivatization followed by analyte enrichment by microextraction by packed sorbent (MEPS) coupled directly to programmed temperature vaporizer–gas chromatography–mass spectrometry (PTV–GC–MS). The MEPS variables, such as sample volume, elution solvent, elution volume, fill and injection speed and washing steps were optimized. It was possible to use the MEPS polymer (silica-C18) 250 times. Ibuprofen-d3 was used as internal standard.
The reproducibility of the method, calculated as the relative standard deviation (RSD), was below 10% for all compounds. Detection limits in ultrapure water were between 3.0 and 110
ng
L
−1 for ibuprofen and ketoprofen, respectively. External calibration was used in the determination of NSAIDs in several types of water samples, including tap, river, sea and influent and effluent wastewater. The results obtained revealed the presence of ibuprofen and naproxen in the influent wastewater sample and of naproxen in the effluent wastewater sample.
Microplastics (MPs) affect plankton (a basis of the trophic chain) and planktivorous fish can ingest them through food confusion or by trophic transmission. Consensus to determine MPs in plankton is ...lacking and, so, three digestion treatments were evaluated: Alkaline (potassium hydroxide) and enzymatic (protease plus lipase) digestions, both combined with a hydrogen peroxide stage; and an oxidative method using a surfactant (sodium dodecyl sulfate) plus hydrogen peroxide. The alkaline method using potassium hydroxide was found to damage polystyrene. MPs were identified with a stereomicroscope and characterized by reflectance infrared microscopy in semi-automatic mode (using dedicated multi-well aluminium plates). Analytical recoveries for polypropylene, polystyrene, polyethylene, polyamide, polyvinyl chloride and polyethylene terephthalate were higher than 75%, 82% and 83% for the alkaline, enzymatic and oxidative treatments, respectively. The enzymatic method was successfully validated in a European interlaboratory exercise and the oxidative method was demonstrated to be a reliable, fast and cheaper alternative.
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•A cost-efficient, plastic-safe protocol was developed to digest plankton samples.•Combining alkaline and oxidative treatments can be harmful in polystyrene MPs.•Multi-well plates reduced the measurement time in a FTIR microscope.•The enzymatic method was validated in a European interlaboratory exercise.•The oxidative method is a reliable (and cheaper) alternative to the enzymatic one.
Polycyclic aromatic hydrocarbons (PAHs) inhalation bioaccessibility was assessed in 65 atmospheric particulate matter samples (PM10) collected at an Atlantic coastal European urban site. The proposed ...method consists on a physiologically based extraction (PBET) by using Gamble’s solution followed by a vortex assisted liquid-liquid micro-extraction (VALLME) and quantification by high performance liquid chromatography with fluorescence detection (HPLC-FLD). The use of a micro-extraction technique combined with FLD detection, provides a simple, fast, sensitive, accurate and low-cost methodology to PAHs quantification in bioaccessible fractions. Accuracy of the bioaccessibility study was assessed by means of a mass balance approaches using a PM10 filter and a certified reference material (ERM-CZ100). High-moderate inhalation bioaccessibilities were found for phenanthrene (Phe), fluoranthene (Ft) and pyrene (Pyr) (average ratios in the 52–65% range); while dibenz (a,h)anthracene (DBahA), indeno (1,2,3-cd)pyrene (IP) and benzo (g,h,i)perylene (BghiP) were observed to be less bioaccessibles (average ratios in the 11–14% range). Relationship between PM10 composition (major ions, trace metals, equivalent black carbon (eBC) and UV-absorbing particulate matter (UVPM)) and PAHs bioaccessibility ratios was also assessed. Principal Component Analysis (PCA) showed that PAHs bioaccessibility percentage is dependent on anthropogenic (eBC, UVPM and Sb concentrations) and marine sources of PM10. Predicted PAHs bioaccessibilities after applying a multiple linear regression model based on marine and anthropogenic source of PM10 could also be established. Health risk assessment of target PM10-associated PAHs via inhalation was assessed considering bioaccessibility concentrations by using hazard index (HI) and BaP equivalent concentration (BaPeq) approaches, suggesting no carcinogenic risk in the area during the sampling campaign.
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•Inhalation bioaccessibility of PM10-associated PAHs was estimated by Gamble’s solution.•PAHs bioaccessibilities decreased when the number of rings were increased.•Correlation between PM10 properties and PAHs bioaccessibility percentages were observed.•Inhalation health risk assessment posed by PM10-associated PAHs was estimated using bioaccessible fraction.
Since the Directive 2013/39/EU included terbutryn to the list of priority substances of all water bodies, a previous method based on dispersive liquid–liquid micro-extraction (DLLME) for the ...determination of triazines in seawater has been modified. The main change consisted on the use of tandem mass spectrometry instead of diode array as detection technique. Due to the higher sensitivity of mass detector, sample volume was reduced and extraction solvent volume was optimized. The optimum extraction conditions were 5 mL of sample, 50 µL of 1-octanol and an agitation step instead of disperser solvent. The obtained analytical recoveries (73%–101% with relative standard deviations below 4%) meeting the requirements. The limits of quantification (between 0.016 and 0.021 µg L
−1
) were more than 10 times lower than the limit set by the European Directive 2013/39/EU for terbutryn (0.34 µg L
−1
). The proposed method was applied to the determination of the target compounds in seawater samples from A Coruña (Galicia, NW of Spain).
The feasibility of stir-bar sorptive extraction (SBSE) followed by liquid desorption in combination with large volume injection (LVI)-in port silylation and gas chromatography–mass spectrometry ...(GC–MS) for the simultaneous determination of a broad range of 46 acidic and polar organic pollutants in water samples has been evaluated. The target analytes included phenols (nitrophenols, chlorophenols, bromophenols and alkylphenols), acidic herbicides (phenoxy acids and dicamba) and several pharmaceuticals. Experimental variables affecting derivatisation yield and peak shape as a function of different experimental PTV parameters initial injection time, pressure and temperature and the ratio solvent volume/
N-(
tert-butyldimethylsilyl)-
N-methyltrifluoroacetamide (MTBSTFA) volume were first optimised by an experimental design approach. Subsequently, SBSE conditions, such as pH, ionic strength, agitation speed and extraction time were investigated. After optimisation, the method failed only for the extraction of most polar phenols and some pharmaceuticals, being suitable for the determination of 37 (out of 46) pollutants, with detection limits for these analytes ranging between 1 and 800
ng/L and being lower than 25
ng/L in most cases. Finally, the developed method was validated and applied to the determination of target analytes in various aqueous environmental matrices, including ground, river and wastewater. Acceptable accuracy (70–130%) and precision values (<20%) were obtained for most analytes independently of the matrix, with the exception of some alkylphenols, where an isotopically labelled internal standard would be required in order to correct for matrix effects. Among the drawbacks of the method, carryover was identified as the main problem even though the Twisters were cleaned repeatedly.
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