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Sunesen Tennant posted an update a month ago
A comparison of two pretreatment approaches, acetonitrile precipitation and accelerated solvent extraction, was carried out. Furthermore, an in-depth examination of how different extraction parameters, such as extraction duration, temperature regime, and the number of cycles, impacted the results was carried out. Detailed investigation of the chromatographic separation conditions, comprising the column, temperature, and elution technique, culminated in optimal settings. Accompanying this effort, investigation into mass spectrometry parameters, including collision energy and declustering potential for the targeted compound’s ion pairs, was undertaken. Reliable data were gathered using the best pretreatment methods and detection parameters, as determined through experimental results. The accelerated solvent extractor, with deionized water as the extraction solvent, was used to process blood and urine samples. Centrifugal ultrafiltration and 0.22 µm membrane filtration were employed sequentially to collect the supernatant, which was diluted by a factor of 50 before injection into the chromatographic column for its detection. The eluent, a 150 mmol/L KOH solution, was used for the isocratic elution procedure on an Ion Pac AS20 IC column. Following suppression, the effluent was fed into a triple quadrupole mass spectrometer, which performed MS/MS (ESI-) analysis in multiple reaction monitoring (MRM) mode. At a collision energy of -150 eV for CE and -200 V for DP, the observed ion mass-to-charge ratio (m/z) ranged from 570 to 770. A quantitative analysis was performed using an externally established standard method. The fluoroacetic acid concentration displayed a strong linear trend within the range of 0.5 to 5000 g/L, characterized by a correlation coefficient (r) greater than 0.999. The limits of detection (LOD) and quantification (LOQ) were found to be 0.014 g/L and 0.047 g/L, respectively. Blood and urine recoveries of fluoroacetic acid ranged from 934% to 958% and 962% to 984%, respectively. The intra-day relative standard deviations (RSDs) for blood and urine samples were 8%–16% and 2%–10%, respectively. The inter-day RSDs, however, were significantly higher, ranging from 23%–38% for blood and 39%–69% for urine. The matrix effects of this method in blood and urine were found to be relatively insignificant, at -74% for blood and -30% for urine, following further investigation. In a poisoning case, the existing approach accurately determined the presence of fluoroacetic acid in the victim’s blood and urine, leading to crucial evidence that expedited the case resolution. rsv signal Conventional detection methods were demonstrably outperformed by the efficiency of the method. The resultant method, in conclusion, exhibits high sensitivity and reliable repeatability, making it well-suited for the prompt detection of fluoroacetic acid in human blood and urine samples. In addition, the method’s independence from derivatization procedures ensures both simplicity and efficiency.
Disinfection byproducts (DBPs), specifically halobenzoquinones (HBQs), are now commonly detected in treated tap water, including entrainment water, and this has prompted increased interest. The water treatment process, employing chlorine, chloramine, and chlorine dioxide as disinfectants, produces these compounds, which demonstrate toxicity exceeding that of regulated disinfection by-products, such as trihalomethanes and haloacetic acids. Harmful to the nervous system, HBQs are recognized as possible causes of bladder cancer. Their effects also include genotoxic actions, resulting in oxidative damage being inflicted upon DNA and proteins. A rise in HBQs in aquatic products is projected due to the substantial enhancement in the disinfection procedures applied to public facilities in recent years. Therefore, an analytical method capable of reliably and accurately detecting HBQs in aquatic items is of substantial importance. Water analysis for identifying and quantifying HBQs can employ various techniques, such as gas chromatography, gas chromatography coupled with mass spectrometry, electrochemical methods, liquid chromatography, and liquid chromatography combined with tandem mass spectrometry. Currently, to the best of our knowledge, there are no available reports detailing the determination of HBQ concentrations in seafood. Subsequently, pretreatment is an absolute necessity for the proper determination of HBQ, considering the intricate matrix effects from aquatic products. A sensitive and accurate method for the simultaneous determination of five HBQs in aquatic products was developed using the QuEChERS technique coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The extraction solvent and adsorbent components of the QuEChERS pretreatment were systematically evaluated to achieve optimal performance. After being extracted with a 10 mL solution of 10% methanol in acetonitrile (containing 0.1% formic acid), the sample underwent dehydration and centrifugation procedures, employing both sodium chloride and anhydrous magnesium sulfate. A QuEChERS packing material, comprised of 50 mg N-propylethylenediamine (PSA), 30 mg graphitized carbon black (GCB), and 30 mg neutral alumina (Al2O3), was used to purify the supernatant, which was subsequently dried with nitrogen and concentrated. A Waters ACQUITY UPLC BEH C18 column (100 mm × 2.1 mm, 1.7 µm) was employed for the separation of five HBQs. A gradient elution program using 0.25% acetonitrile formate solution and 0.25% formic acid aqueous solution as the mobile phase was utilized. The separated HBQs were then detected using UPLC-MS/MS with negative electrospray ionization (ESI-) in multiple reaction monitoring (MRM) mode. Quantitative data analysis relied on a matrix-matched external standard methodology. The proposed method enabled rapid separation of the five HBQs within a mere 6 minutes, demonstrating a substantially reduced separation time relative to prior studies. To evaluate the matrix effect, a matrix-matched calibration curve was developed. The findings revealed 25-dichloro-14-benzoquinone (25-DCBQ) to possess a matrix-boosting characteristic, while the remaining HBQs demonstrated a matrix-suppressing effect. Tetrachlorobenzoquinone (TCBQ) stood out in its strong inhibitory capacity. Under rigorously controlled experimental conditions, the five HBQs displayed a linear relationship throughout the 10-500 grams per liter range, characterized by correlation coefficients (r) of 0.9992 or higher. The method’s detection limits ranged from 0.015 to 0.008 grams per kilogram, and target compound recoveries varied from 85.9% to 116.5%. The observed relative standard deviations, varying from 14% to 82%, indicate good reproducibility of the results. The proposed method’s successful application to sample analysis revealed the presence of 26-dichloro-3-methyl-14-benzoquinone (26-DCMBQ) in grass carp specimens. For the simultaneous determination of five HBQs in aquatic products, a convenient, sensitive, accurate, and suitable approach has been developed. Subsequently, the formulated method supplies a dependable point of comparison for the habitual tracking of trace HBQs in food samples.
Drinking water disinfection is vital for the prevention of waterborne diseases. One unforeseen effect of water disinfection is the creation of disinfection by-products, which arise from the reaction between disinfectants and organic materials (natural or man-made) along with halides. These by-products have considerable toxicological and carcinogenic implications. Due to their severe toxicity and high detection frequency, halobenzoquinones (HBQs), a nascent disinfection by-product, are now receiving increased attention. Precisely determining HBQs is crucial for subsequent investigations into their incidence, toxicity, and preventive measures; nevertheless, drinking water often contains HBQs at extremely low levels. Hence, reliable and rapid analytical procedures are crucial for determining and quantifying HBQ. This study developed a method combining solid-phase extraction (SPE) and ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS) to quantify 13 halogenated benzoquinones (HBQs), including six chlorobenzoquinones, six bromobenzoquinones, and one iodobenzoquinone, in potable water samples. One-liter water samples were treated with 25 milliliters of formic acid, and 500 milliliters from each were collected for further enrichment studies. The SPE column, the washing solvent, and the nitrogen purging temperature were instrumental in pretreatment optimization efforts. After extraction with Plexa SPE columns (200 mg/6 mL), a wash step with a mixture of ultrapure water, 0.25% formic acid and 30% methanol, also containing 0.25% formic acid, was performed on the samples. The samples were subsequently eluted with 6 mL of methanol containing 0.25% formic acid, followed by nitrogen blowing at 30°C. Refinement of the UPLC-MS/MS parameters involved a comparative analysis of data from two reversed-phase columns (BEH C18 and HSS T3), differing concentrations of formic acid in the mobile phase, and the establishment of the best instrumental conditions. The HSS T3 column (100 mm × 21 mm, 18 m) facilitated the separation of 13 HBQs by gradient elution with a mobile phase of 0.1% formic acid aqueous solution and methanol over 16 minutes. Utilizing a triple quadrupole mass spectrometer with a negative electrospray ionization (ESI-) source operating in multiple reaction monitoring (MRM) mode, the 13 HBQs were identified. For the determination of HBQ quantities, matrix-matched calibration curves were employed, due to substantial matrix inhibitory interference. The results demonstrably highlighted strong linear relationships among the 13 HBQs, yielding correlation coefficients (r) exceeding 0.999. Method detection limits (MDLs, defined by a signal-to-noise ratio of 3) were observed to range from 2 to 100 ng/L; the corresponding method quantification limits (MQLs, signal-to-noise ratio of 10) spanned a range from 6 to 330 ng/L. At three distinct concentrations (10, 20, and 50 ng/L), the 13 HBQs exhibited recovery rates ranging from 56% to 88%, with relative standard deviations (RSDs, n=6) no greater than 92%.