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Jensen Magnussen posted an update 6 months, 2 weeks ago
0.2 μg/L to 2.2 μg/L for the PAEs. The limits of quantification (LOQs, S/N=10) ranged from 0.006 μg/L to 0.23 μg/L for the PAHs and from 0.8 μg/L to 7.4 μg/L for PAEs. The proposed method is simple, fast, low-cost, and environmentally friendly, and it is suitable for the rapid determination of trace PAHs and PAEs in surface water samples.Dacarbazine (DTIC) is a first-line chemotherapy drug that is widely used in clinical practice for malignant melanoma. DTIC is metabolized by the liver in vivo. Some drugs are excreted in urine in the form of a prototype. Hence, DTIC in urine can be monitored to evaluate its utilization and conversion rate in the human body, and then to determine its therapeutic effect. Urine is the only body fluid that can be obtained in large quantities without damage, and it plays an important role in the analysis of body functions. However, the composition of urine is complex and there is large matrix interference, because of which trace analysis or trace component analysis is difficult. At present, the main analytical methods for DTIC are high performance liquid chromatography (HPLC) with/without mass spectrometry (MS). HPLC and HPLC-MS have the advantages of good separation effect, good selectivity, high detection sensitivity, automatic operation, and wide application range. Unfortunately, DTIC is a strongly polar and wemethod was successfully applied to monitor the change in DTIC concentration in the urine of C57BL/6 mice in various stages of melanoma. The results demonstrate that the method is simple, reliable, and easy to apply.Paraquat (PQ) and diquat (DQ) are widely used as non-selective contact herbicides. Several cases involving accidents, suicide, and homicide by PQ or DQ poisoning have been reported. Poising by PQ, which is mainly concentrated in the lungs, causes acute respiratory distress syndrome and leads to multiple organ toxicity. The toxic effects of DQ are similar to those of PQ but relatively less intense. click here The mortality rates in PQ and DQ poisoning are high. Simultaneous monitoring of the PQ and DQ concentrations in plasma and urine can provide valuable information for early clinical diagnosis and prognosis. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is the main analytical method used to detect PQ and DQ in plasma and urine. As both these compounds are highly polar and water soluble, they cannot be retained effectively on a reversed-phase column with conventional mobile phases. The separation of PQ and DQ by ion-pair chromatography or hydrophilic chromatography has been reported. The x effects of PQ and DQ in plasma were 84.2%-89.3% and 84.7%-91.1%, while the average matrix effects of PQ and DQ in urine were 50.3%-58.4% and 51.9%-59.4%. The average recoveries of PQ and DQ in plasma were 93.5%-117% and 91.7%-112%, respectively, with relative standard deviations (RSDs) of 3.4-16.7% and 2.8%-13.2%, and that in urine were 90.0%-118% and 99.2%-116%, with relative standard deviations of 5.6%-14.9% and 2.4%-17.3% (n=6). The limits of detection of PQ and DQ in plasma and urine were 0.3 μg/L and 0.2 μg/L, respectively, with the corresponding limits of quantification being 1.0 μg/L and 0.5 μg/L. This method is sensitive and accurate, and it can be used to determine PQ and DQ for clinical diagnosis and prognosis in patients.A method was established for the determination of N-nitrosodimethylamine (NDMA) in metformin hydrochloride active pharmaceutical ingredient (API) and preparation samples by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Water was used as the extraction solvent for the metformin hydrochloride API and preparation samples. The samples were analyzed by HPLC-MS/MS after vortex mixing, constant temperature shaking, high speed centrifugation and microfiltration. An ACE EXCEL 3 C18-AR column (150 mm×4.6 mm, 3 μm) was used for chromatographic separation. The mobile phases were water and methanol both containing 0.1% formic acid with gradient elution. The flow rate, column temperature, and autosampler temperature were set as 0.8 mL/min, 40℃, and 10℃, respectively. The valve switching technique was used to protect the mass spectrometer, while six-way valve switching was adopted to allow the mobile phase with a retention time of 2.85-7.00 min to enter the mass spectrometer and the mobile phaw materials and preparation samples.An analytical method was established for the determination of trace α-amanitin in the urine of patients suffering from mushroom poisoning by online solid phase extraction-liquid chromatography-tandem mass spectrometry (online SPE-LC-MS/MS). The sample was protein precipitated with formic acid acidified acetonitrile-methanol (51, v/v). Reversed-phase liquid-liquid microextraction was used to remove the organic solvent from the sample extract. The toxin was purified by online SPE using an ODS micro column (5 mm×2.1 mm, 5 μm), and separated on an XBridgeTM BEH C18 column (150 mm×3.0 mm, 2.5 μm). Finally, the toxin was measured by MS/MS in the negative electrospray ionization (ESI-) mode. Multiple reaction monitoring (MRM) was used, and the conditions were m/z 917.4>205.1 (quantitative ion transition) and m/z 917.4>257.1. Collision energy for both transitions was 55 eV. A fast valve-switching technique with a quantitative loop was used as an interface between the online SPE and LC-MS/MS modules. The two modules w by the application to the analysis of actual samples. The protein precipitation and reversed-phase liquid-liquid microextraction steps are fast and simple. Hence, they can be used as a rapid and effective pre-treatment method for online SPE-LC-MS/MS analysis of water-soluble toxins in biomaterial matrix. Highly sensitive analysis of α-amanitin in urine can be obtained using a precise purification technology via online SPE in this study. The problem of qualitative confirmation of the toxin at trace levels (0.03 μg/L) after poisoning can be solved. The laboratory identification time for amatoxin poisoning in some patients exceeds 90 h. The developed analytical method at trace level (0.1 μg/L of LOQ) can provide reliable technical support for establishing the dose-response relationship of α-amanitin in vivo. It can satisfy for the determination of trace α-amanitin in urine samples from patients with hepatotoxic mushroom poisoning.