•EC50 procainamide growth rate/chlorophyll (mg/l): 104/143 (alone).•EC50 procainamide growth rate/chlorophyll (mg/l): 125/31 (with microplastics).•EC50 doxycycline growth rate/chlorophyll (mg/l): ...39/24 (alone).•EC50 doxycycline growth rate/chlorophyll (mg/l): 21/13 (with microplastics).•Microplastics presence increased pharmaceuticals toxicity.
Microplastics and pharmaceuticals are considered ubiquitous and emergent pollutants of high concern but the knowledge on their effects on primary producers is still limited, especially those caused by mixtures. Thus, the goal of the present study was to investigate if the presence of microplastics (1–5 μm diameter) influences the toxicity of the pharmaceuticals procainamide and doxycycline to the marine microalga Tetraselmis chuii. Bioassays (96 h) to investigate the toxicity of those substances individually and in mixtures (i.e. microplastics-procainamide mixtures and microplastics-doxycycline mixtures) were carried out. Effect criteria were the average specific growth rate (growth rate) and chlorophyll a concentration (chlorophyll). EC10, EC20 and EC50 were determined. Microplastics alone had no significant effects on growth rate up to 41.5 mg/l, whereas chlorophyll was significantly reduced at 0.9 and 2.1 mg/l of microplastics, but not at higher concentrations. The 96 h EC50 (growth rate and chlorophyll, respectively) determined for the other bioassays were: 104 and 143 mg/l for procainamide alone; 125 and 31 mg/l for procainamide in the presence of microplastics; 22 and 14 mg/l for doxycycline alone; 11 and 7 mg/l for doxycycline in the presence of microplastics. Significant differences (p < 0.001) between the toxicity curves of each pharmaceutical alone and in mixture with microplastics were found for procainamide (chlorophyll), and doxycycline (both parameters). Thus, both pharmaceuticals were toxic to T. chuii in the low ppm range, and microplastics-pharmaceutical mixtures were more toxic than the pharmaceuticals alone. Very high decreases of doxycycline concentrations in test media were found, indicating degradation of the antibiotic. Thus, although the biological results are expressed in relation to doxycycline concentration, the effects were likely caused by a mixture of the parental compound and its degradation products. The concentrations of microplastics and pharmaceuticals tested (low ppm range) are higher than those expected to be found in waters of the most part of marine ecosystems (ppt or ppb ranges). However, considering the widespread contamination by microplastics and pharmaceuticals, the concentrations already found in waters, sediments and/or organism of heavily polluted areas, the long-term exposure (over generations) of wild populations to such substances in polluted ecosystems and the possibilities of bioaccumulation and toxicological interactions, these findings are of concern and further research on microplastics-pharmaceuticals toxicological interactions is needed.
Drinking water sources are increasingly subject to various types of contamination due to anthropogenic factors and require proper treatment to remove disease-causing agents. Public drinking water ...systems use different treatment methods to provide safe and quality drinking water to populations. However, they are ineffective in removing contaminants that are considered a danger to the environment and therefore to humans. Several alternative treatment processes have been proposed, such as membrane filtration, as final purification methods. This paper aims to summarize the type of pollutant compounds, filtration processes, and membranes that have been most studied in this area with particular emphasis on how the modification of membranes, either the manufacturing process or the incorporation of nanomaterials, influences their performance.
The evaluation of the biogenic amines (BAs) profile of different types of craft beers is herein presented. A previously developed and validated analytical method based on ion-pair chromatography ...coupled with potentiometric detection was used to determine the presence of 10 BAs. Good analytical features were obtained for all amines regarding linearity (R
values from 0.9873 ± 0.0015 to 0.9973 ± 0.0015), intra- and inter-day precision (RSD lower than 6.9% and 9.7% for beer samples, respectively), and accuracy (recovery between 83.2-108.9%). Detection and quantification limits range from 9.3 to 60.5 and from 31.1 to 202.3 µg L
, respectively. The validated method was applied to the analysis of four ale beers and one lager craft beer. Ethylamine, spermidine, spermine, and tyramine were detected in all analyzed samples while methylamine and phenylethylamine were not detected. Overall, pale ale beers had a significantly higher total content of BAs than those found in wheat pale and dark samples. A general least square regression model showed a good correlation between the total content of BAs and the brewing process, especially for Plato degree, mashing, and fermentation temperatures. Knowledge about the type of ingredients and manufacturing processes that contribute to higher concentrations of these compounds is crucial to ensuring consumer safety.
The determination of metal ions is important for nutritional and toxicological assessment. Atomic spectrometric techniques are highly efficient for the determination of these species, but the high ...costs of acquisition and maintenance hinder the application of these techniques. Inexpensive alternatives for metallic element determination are based on dedicated biosensors. These devices mimic biological systems and convert biochemical processes into physical outputs and can be used for the sensitive and selective determination of chemical species such as cations. In this work, an overview of the proposed biosensors for metal ions determination was carried out considering the last 15 years of publications. Statistical data on the applications, response mechanisms, instrumentation designs, applications of nanomaterials, and multielement analysis are herein discussed.
The determination of chlortetracycline, doxycycline, oxytetracycline, and tetracycline in milk samples by HPLC coupled to a cucurbit8uril-based potentiometric sensor is herein presented. The new ...tetracycline-selective electrode is based on a polymeric membrane incorporating cucurbit8uril as a macrocyclic host, potassium tetrakis(p-chlorophenyl) borate as an ionic additive, 2-fluorophenyl 2-nitrophenyl ether as a plasticizer, and multi-walled carbon nanotubes as nanostructured materials. A microfluidic wall-jet flow-cell is implemented as a potentiometric detector after chromatographic separation by a C8 column using a gradient mobile phase of sulphuric acid and acetonitrile. The proposed methodology was validated following International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) and European Union (EU) guidelines. Linear regression models provided R2 in the range from 0.9973 ± 0.0026 to 0.9987 ± 0.0012 for all tetracycline antibiotics. The limits of detection and quantification ranged from 13.3 to 46.0 μg L−1 and 44.4 to 92.1 μg L−1, respectively. Precision intra-day, inter-day, and inter-electrode showed relative standard deviation values lower than 12.5%, 13.5%, and 12.9%, respectively. Accuracy was assessed by analysis of spiked milk samples around the maximum residue limit, yielding recovery values in the range from 81.3 to 108.5%. The simple, sensitive, cost-effective, and reliable HPLC-ion-selective electrode method justifies its use as a competitive alternative for the analysis of tetracycline residues in the food quality control sector.
Considering the continuous increment of morbidity in patients with renal disease, the improvement of polymeric membranes characteristics for haemodialysis is a challenging issue. The efficient ...removal of middle size uremic toxins, as well as biocompatibility is crucial characteristics to ameliorate chronic kidney disease patients’ outcomes. In this study, polysulfone membranes with different hydrophilic additives, molecular weight and concentrations were prepared by spin coating method, followed by phase inversion via immersion precipitation. The removal of urea, lysozyme and bovine serum albumin was studied using a miniaturized flow system, mimicking haemodialysis conditions. The optimal composition was 15.0 wt% of polysulfone and 2.5 wt% of polyvinylpyrrolidone K30. This selected membrane was fully permeable for urea, showed up to 50% rejection of lysozyme and very high rejection of albumin. The additive PVP K30 played important role in the improvement of porosity, without compromising the mechanical strength of the membrane. The biocompatibility of membrane was evaluated by material-induced haemolysis and platelet activation tests. The platelet activation and haemolysis were negligible, compared to other biocompatible materials. These results confirmed the haemocompatibility of the optimized membrane. Therefore, the membrane is not expected to modulate the biological response, when used for the haemodialysis treatment.
End-stage renal disease is a growing health problem with increasing prevalence and high health care costs. Patients suffering from end-stage renal disease exhibit higher morbidity and mortality rates ...compared to the general population. These patients, who are treated using hemodialysis, typically suffer from anemia, inflammation, and oxidative stress. Inadequate dialyzer membrane biocompatibility exacerbates these negative side effects. Modifications of the composition of hemodialysis membranes have improved their biocompatibility and improve the patients’ quality of life. Recently, the use of dialyzer membranes coated with bioactive compounds has also been proposed to further ameliorate dialysis-associated problems. Based on a survey of the current literature, application of bioactive membranes decreases the inflammation and oxidative stress of patients treated with hemodialysis.
A flow-batch manifold coupled to a flame atomic absorption spectrometer was evaluated to assess the iron content by the internal standard method in hydrated ethanol used as fuel in automotive ...industry. For this assessment official methods require calibration procedures with matrix matching, making it difficult to obtain accurate results for samples adulterated by the addition of water. Nickel was selected as the internal standard since it is usually absent in samples and because it requires similar conditions of atomization. After procedure optimization, which requires about 4.25
mL of sample and standard per measurement, it was possible to get linear analytical response for iron concentrations between 0.12 and 1.40
mg
L
−1 and a detection limit of 0.04
mg
L
−1. Eighteen samples were collected randomly from fuel stations in Pernambuco (Brazil) and iron concentration was determined using the proposed procedure. Comparison of results obtained (0.20–1.50
mg
L
−1) showed a mean standard error of 3.9%, with 3.8% and 2.3% calculated for the mean variation coefficients of the proposed method and the reference procedure, respectively. For adulterated samples (0.12–0.64
mg
L
−1), the mean standard error was 4.8% when compared with the standard addition method. These results allowed concluding that the proposed procedure is adequate to accomplish the determination of iron in ethanol fuel in a large scale basis with a sampling rate of about 10
h
−1.
A sequential injection analysis system was developed to quantify pH, chloride and nickel in electrolytic baths, in the ranges 1–5 pH units, and 0.1–1.0 and 0.1–1.6
mol
l
−1, respectively. To enable ...pH and chloride determination, potentiometric detection with two ion-selective electrodes in a tubular configuration was used. Nickel concentrations were assessed using colorimetric detection at 660
nm. pH was determined prior to nickel determination and just after sample injection (500
μl) into a 0.025
mol
l
−1 phosphate buffer carrier stream at pH 6.3 and a 9.10
ml
min
−1 flow rate. For chloride determination, on-line dialysis through a cellulose membrane was used to enable sample dilution and matrix separation. A 2
5−1 fractional factorial design based on the carrier solution composition and the levels of the hydrodynamic parameters was used for system optimization. At the optimized settings a sampling rate of 40 samples
h
−1 was attained, with precision and accuracy statistically indistinguishable from those achieved with conventional procedures.
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