In these five cosmetic matrices, the recoveries of the tested substance ranged from 832% to 1032%, while relative standard deviations (RSDs, n=6) fell within the 14% to 56% range. Cosmetic samples of various matrices were screened using this method, revealing five positive samples containing clobetasol acetate at concentrations ranging from 11 to 481 g/g. The method, in essence, is straightforward, sensitive, and trustworthy, thus being suitable for high-throughput qualitative and quantitative screening in diverse cosmetic matrices. The methodology, in addition, furnishes critical technical support and a theoretical foundation for the formulation of suitable detection standards for clobetasol acetate in China, as well as for controlling its presence within cosmetic products. Implementing measures to address illegal additions in cosmetics is heavily influenced by the method's considerable practical significance.
The consistent and widespread application of antibiotics to address ailments and stimulate animal development has left them lingering and accumulating within water, soil, and sediment. Antibiotic pollution, a newly emerging environmental concern, is currently a subject of intense research. Water bodies display a presence of antibiotics, albeit in minuscule traces. A challenge remains in identifying the varied types of antibiotics, each marked by specific physicochemical properties, unfortunately. Accordingly, the need for methods to rapidly, accurately, and sensitively analyze these emerging pollutants in various water specimens necessitates the development of pretreatment and analytical procedures. The optimized pretreatment method was developed based on the features of the screened antibiotics and the sample matrix, particularly concerning the SPE column type, the pH of the water sample, and the amount of ethylene diamine tetra-acetic acid disodium (Na2EDTA) incorporated. A 200 mL water sample, containing 0.5 g of Na2EDTA, was pH-adjusted to 3 using either sulfuric acid or sodium hydroxide solution, prior to extraction. Water sample enrichment and purification were carried out employing an HLB column for the task. HPLC separation was performed using a C18 column (100 mm × 21 mm, 35 μm), with gradient elution driven by a mobile phase of acetonitrile and 0.15% (v/v) aqueous formic acid. Quantitative and qualitative analyses were executed on a triple quadrupole mass spectrometer using multiple reaction monitoring coupled with an electrospray ionization source. The results displayed correlation coefficients well above 0.995, showcasing the presence of very strong linear relationships. The limits of quantification (LOQs) ranged from 92 ng/L up to 428 ng/L; simultaneously, the method detection limits (MDLs) were observed within the 23 to 107 ng/L range. Surface water samples spiked at three different levels showed recoveries for the target compounds in a range of 612% to 157%, and exhibited relative standard deviations (RSDs) varying from 10% to 219%. The percentage recovery of target compounds in wastewater, across three spiked levels, varied from 501% to 129%, while the relative standard deviations (RSDs) spanned a range from 12% to 169%. A successful application of the method provided the capability to simultaneously analyze antibiotics in samples from reservoir water, surface water, sewage treatment plant outfall, and livestock wastewater. Watershed and livestock wastewater samples showed the presence of many antibiotics. A detection frequency of 90% for lincomycin was observed across a collection of 10 surface water samples. Ofloxaccin's concentration peaked at 127 ng/L in livestock wastewater samples. Consequently, the proposed approach exhibits strong performance in terms of model decision-making and recovery, significantly outperforming previous methodologies. This innovative method, leveraging small water samples, extensive applicability, and quick analysis times, stands as a potent tool for rapid and sensitive environmental pollution monitoring during emergencies. A reliable resource for developing antibiotic residue standards is potentially offered by this method. The study's findings substantially enhance our grasp of the environmental occurrences, treatments, and controls for emerging pollutants.
A crucial active ingredient in disinfectant solutions, quaternary ammonium compounds (QACs) are a class of cationic surfactants. A growing trend in QAC use is unsettling, given that inhalation or ingestion can expose individuals to these compounds and lead to adverse effects on respiratory and reproductive health. The primary avenues of QAC exposure for humans are ingestion of food and inhaling contaminated air. Significant harm to public health is associated with the presence and accumulation of QAC residues. To evaluate the potential presence of QAC residue levels in frozen food, a method for the simultaneous detection of six standard QACs and a novel one (Ephemora) was created. This approach used ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and a modified QuEChERS protocol. Sample pretreatment and instrument analysis procedures were fine-tuned to optimize the method's response, recovery, and sensitivity, taking into account the crucial roles of extraction solvents, adsorbent types and dosages, apparatus conditions, and mobile phases. Employing a vortex-shock method, QAC residues were extracted from the frozen food using 20 mL of a methanol-water mixture (90:10, v/v) containing 0.5% formic acid, which was agitated for 20 minutes. CMC-Na chemical The mixture underwent ultrasonic treatment for 10 minutes, followed by centrifugation at 10,000 revolutions per minute for a duration of 10 minutes. From the supernatant, a 1-mL sample was moved to a separate tube and purified using 100 milligrams of PSA adsorbent material. After a 5-minute spin at 10,000 revolutions per minute, and mixing, the purified solution was then subject to analysis. The target analytes were separated on an ACQUITY UPLC BEH C8 chromatographic column (50 mm × 2.1 mm, 1.7 µm) under conditions of a 40°C column temperature and a 0.3 mL/min flow rate. A 1-liter injection volume was utilized. In the positive electrospray ionization (ESI+) mode, multiple reaction monitoring (MRM) was performed. Seven QACs were quantified using the matrix-matched external standard method. The seven analytes were completely separated using the optimized chromatography-based method. The seven QACs demonstrated linear responses across the concentration spectrum from 0.1 to 1000 ng/mL. The correlation coefficient r², exhibited values spanning from 0.9971 to 0.9983. The detection limit spanned a range from 0.05 g/kg to 0.10 g/kg, while the quantification limit ranged from 0.15 g/kg to 0.30 g/kg. The current legislation was followed when salmon and chicken samples were spiked with 30, 100, and 1000 grams per kilogram of analytes to ensure accuracy and precision, using six replicates for each measurement. The average recovery rates of the seven QACs displayed a difference between 654% and 101%. CMC-Na chemical RSDs for the relative standard deviations were observed to fall within the range of 0.64% and 1.68%. Upon PSA purification, the matrix effects affecting the analytes in salmon and chicken samples were observed to range from a negative 275% to 334%. To determine the presence of seven QACs in rural samples, the developed method was employed. Amongst the samples examined, only one showed the presence of QACs; the concentration did not exceed the residue limit set by the European Food Safety Authority. The detection method stands out for its high sensitivity, good selectivity, and consistent stability, which translate into accurate and dependable results. Frozen food can be rapidly and simultaneously analyzed for seven QAC residues using this method. The results obtained offer valuable information, crucial for future risk assessment studies, particularly for compounds within this category.
Although widely deployed in agriculture to protect food crops, pesticides frequently result in detrimental effects on ecosystems and human populations. Pervasiveness of pesticides in the environment, along with their harmful properties, has resulted in substantial public concern. Among the world's largest users and producers of pesticides is China. Nevertheless, restricted data exist concerning pesticide exposure in human subjects, necessitating a technique for the precise measurement of pesticides in human specimens. Using 96-well plate solid phase extraction (SPE) coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), this study successfully developed and validated a sensitive method for the precise quantification of two phenoxyacetic herbicides, two organophosphorus pesticide metabolites, and four pyrethroid pesticide metabolites in human urine. A systematic optimization process was applied to the chromatographic separation conditions and MS/MS parameters. Ten different solvents were selected for the meticulous extraction and subsequent cleanup of human urine samples. Within a single analytical run, the targeted compounds in the human urine samples exhibited excellent separation, completing within 16 minutes. Human urine, a 1 mL aliquot, was mixed with 0.5 mL of 0.2 mol/L sodium acetate buffer, and subsequently hydrolyzed at 37°C overnight using the -glucuronidase enzyme. An Oasis HLB 96-well solid phase plate was used to extract and clean the eight targeted analytes prior to elution with methanol. A UPLC Acquity BEH C18 column (150 mm × 2.1 mm, 1.7 μm) facilitated the separation of the eight target analytes, achieved through gradient elution with 0.1% (v/v) acetic acid in acetonitrile and 0.1% (v/v) acetic acid in water. CMC-Na chemical The multiple reaction monitoring (MRM) mode, under negative electrospray ionization (ESI-), was used to identify the analytes, which were subsequently quantified using isotope-labelled analogs. Para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TCPY), and cis-dichlorovinyl-dimethylcyclopropane carboxylic acid (cis-DCCA) displayed excellent linearity across a concentration range of 0.2 to 100 g/L. Conversely, 3-phenoxybenzoic acid (3-PBA), 4-fluoro-3-phenoxybenzoic acid (4F-3PBA), 2,4-dichlorophenoxyacetic acid (2,4-D), trans-dichlorovinyl-dimethylcyclopropane carboxylic acid (trans-DCCA), and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) demonstrated linearity from 0.1 to 100 g/L, with correlation coefficients exceeding 0.9993 in all cases.