[Determination of 26 bisphenols in dust by ultra performance liquid chromatography-tandem mass spectrometry].

Bisphenol A (BPA) is one of the most widely produced compounds in the world and was listed as a substance of very high concern by the European Chemicals Agency in 2016. Because of its toxicity, many countries and regions, including China, have banned BPA addition in feeding-bottles. And the European Union (EU) has banned BPA use in other food contact materials and thermal paper. Restrictions on BPA have contributed to the widespread use of alternatives. As the toxicity of BPA alternatives continues to be revealed, the alternatives of BPA alternatives are being developing. As the most extensive alternative for BPA, bisphenol S (BPS) was proven to have estrogen-disrupting effects and developmental toxicity of the neuroendocrine system. Therefore, BPS alternatives are used in thermal paper. In this study, alternatives to both BPA and BPS are collectively referred to as bisphenols (BPs). As a pooling matrix of many indoor chemicals, dust is an important pathway for human exposure to BPs. BPA and its alternatives are routinely detected in dust. As BPS alternatives have been detected in recycled paper and sludge, it is also very important to detected in dust. However, common analytical methods for BPs have low sensitivity and contain few BPS alternatives. Therefore, a high-throughput, high-accuracy, and high-sensitivity method must be established for the determination of BPs in dust; this will lay the foundation for subsequent studies on the environmental behavior and exposure risk of BPs. In this study, an ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of 26 variations of BPs in dust. UPLC-MS/MS parameters of the variations were optimized to compare the separation effect and response intensity in different columns and mobile phases. The influence of the extraction solvent and solid phase extraction (SPE) on the extraction efficiency and purification effect of target compounds were optimized by using the isotopic internal standard method, and the 26 variations of BPs in dust was quantitatively analyzed. Finally, the dust samples were extracted by using 3 mL of acetonitrile and 3 mL of a 50% methanol aqueous solution in an ultrasound bath. The combined extract was further purified by using an Oasis HLB cartridge (60 mg/3 mL). The cartridge was then washed with a 40% methanol aqueous solution (0.5 mL) and eluted with methanol (2 mL). The target compounds were separated on a CORTECS® UPLC® C18 column (100 mm×2.1 mm, 1.6 µm), with methanol and 1 mmol/L ammonium fluoride solution as mobile phases and a flow rate of 0.3 mL/min. Electrospray ionization (ESI) was applied in the positive, negative, and multiple reaction monitoring (MRM) modes for the mass scan. Under optimized conditions, the linear ranges of the 26 targets behaved well linearly in their respective ranges with correlation coefficients (r2)>0.999. The limits of detection (LODs) and limits of quantification (LOQs) were assessed using signal-to-noise (S/N) ratios of 3 and 10, respectively. The LODs and LOQs of the method were 0.01-0.75 µg/kg and 0.02-2.50 µg/kg, respectively. The accuracy of the method was evaluated by conducting a recovery test at three spiked levels: LOQ, two times the LOQ, and 10 times the LOQ, with the average recoveries ranging from 83.7% to 114.9%. The precision of the method was evaluated by using the relative standard deviation (RSD). The intra-day RSDs and inter-day RSDs were 0.86%-9.79% (n=6) and 5.16%-19.5% (n=6), respectively. The established method was used to determine 11 dust samples. Fifteen BPs were detected at a detection rate of 9.1%-100.0%. The detection rate for BPA, BPS, bisphenol F (BPF), 4-hydroxy-4'-isopropoxydiphenylsulfone (BPSIP), and diphenyl sulfone (DPS) was 100.0%. BPSIP, 4-allyloxy-4'-hydroxydiphenyl sulfone (BPS-MAE), and bis-(3-allyl-4-hydroxyphenyl) sulfone (TGSA) were first detected in Chinese dust, whereas 4-benzyloxy-4'-hydroxydiphenyl sulfone (BPS-MPE), 4-hydroxybenzoic acid benzyl (PHBB), and DPS were first detected in dust samples worldwide. This method is simple, rapid, and sensitive, and is suitable for the qualitative screening and quantitative analysis of the 26 BPs in dust samples.

[Determination of 14 paralytic shellfish toxins in plasma and urine by ultra-high performance liquid chromatography-tandem mass spectrometry].

The detection of paralytic shellfish toxins in human biological matrices is important for the diagnosis and treatment of food poisoning caused by them. An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for the determination of 14 paralytic shellfish toxins in plasma and urine. The effect of solid phase extraction (SPE) cartridges was also investigated and the pretreatment and chromatographic conditions were optimized. Under these optimal conditions, 0.2 mL water, 0.4 mL methanol, and 0.6 mL acetonitrile were successively added to plasma and urine samples for extraction. The supernatants from plasma extraction were subjected to an UHPLC-MS/MS analysis, whereas the supernatants from urine extraction were further purified using polyamide (PA) SPE cartridges and then analyzed by UHPLC-MS/MS. Chromatographic separation was conducted on a Poroshell 120 HILIC-Z column (100 mm×2.1 mm, 2.7 µm) with a flow rate of 0.5 mL/min. The mobile phase was 0.1% (v/v) formic acid aqueous solution containing 5 mmoL/L ammonium formate and acetonitrile containing 0.1% (v/v) formic acid. The analytes were detected in the multiple reaction monitoring (MRM) mode after being ionized by an electrospray ion (ESI) in positive and negative modes. Quantitation of the target compounds was performed using the external standard method. Under the optimal conditions, the method showed good linearity in the range of 0.24-84.06 µg/L, with correlation coefficients greater than 0.995. The limits of quantification (LOQs) for the plasma and urine samples were 1.68-12.04 ng/mL and 4.80-34.4 ng/mL, respectively. The average recoveries for all the compounds were 70.4%-123.4% at spiked levels of 1, 2, and 10 times the LOQs, the intra-day precisions were 2.3%-19.1% and the inter-day precisions were 5.0%-16.0%. The established method was used to determine the target compounds in the plasma and urine from mice intraperitoneally injected with 14 shellfish toxins. All 14 toxins were detected in the 20 urine and 20 plasma samples, with contents of 19.40-55.60 µg/L and 8.75-13.86 µg/L, respectively. The method is simple, sensitive, and only requires a small amount of sample. Therefore, it is highly suitable for the rapid detection of paralytic shellfish toxins in plasma and urine.

Effect of Biliary Drainage on the Toxicity and Toxicokinetics of Amanita exitialis in Beagles.

Amatoxin poisoning induces delayed-onset acute liver failure, which are responsible for more than 90% of deaths in mushroom poisoning. It has been postulated from animal and human studies that biliary drainage interrupting enterohepatic amatoxin circulation may affect amatoxin poisoning. Dogs were randomly divided into four groups of six animals each. In 20 mg/kg and 60 mg/kg with biliary drainage groups, after accepting bile drainage operation, beagles were fed Amanita exitialis powder (20 or 60 mg/kg) in starch capsules. In control and bile drainage groups, the beagle dogs were fed with empty capsules. They were assessed for toxicity signs, biochemical and pathological changes, and peptide toxins in plasma, urine and bile. The data were directly compared with those from our published studies on Amanita exitialis-exposed beagles without biliary drainage. Amatoxins were rapidly absorbed and eliminated from plasma after Amanita exitialis ingestion. Amatoxins in 0⁻1-day urine accounted for more than 90% of the total urine excretion, and amatoxins in bile accounted for less than 20% of the total urine and bile excretion. The dogs with biliary drainage showed less severe toxicity signs and biochemical and pathological changes and much lower internal exposure than dogs without biliary drainage. Biliary drainage caused a more than 70% reduction in intestinal amatoxin absorption and could reduce amatoxin absorption from the gastrointestinal tract.

Toxicity and toxicokinetics of Amanita exitialis in beagle dogs.

In this study, the toxicology of A. exitialis, a lethal mushroom found in China, and the toxicokinetics of peptide toxins contained in it were evaluated. Beagles were fed A. exitialis powder (20 or 60 mg/kg) in starch capsules, after which they were assessed for signs of toxicity, as well as biochemical and pathological changes. Ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry was used to assay the peptide toxins. The total peptide toxins in A. exitialis was 3482.6 ±â€¯124.94 mg/kg. The beagles showed signs of toxicity, such as vomiting and diarrhea, at 12-48 h following ingestion of A. exitialis. Furthermore, alanine transaminase and aspartate transaminase levels in plasma, as well as prothrombin time and activated partial thromboplastin time peaked at 36 h post A. exitialis ingestion. Furthermore, total bilirubin and alkaline phosphatase levels peaked at 48 h after A. exitialis ingestion. Three dogs that were administered 60 mg/kg A. exitialis died at 24-72 h after ingesting the capsules. Additionally, liver histopathological examinations showed hemorrhagic necrosis of hepatocytes. α-Amanitin, ß-amanitin, and phallacidin were rapidly absorbed and eliminated from plasma after A. exitialis was ingested. A long latency period (12-24 h post A. exitialis ingestion) was observed in the dogs before the onset of gastrointestinal symptoms. There was acute liver damage thereafter. Gastric lavage and enhanced plasma clearance methods such as hemodialysis, hemoperfusion, or plasma exchange may be ineffective in removing amatoxins from blood at 12 h post A. exitialis ingestion. Enhanced excretion of amatoxins in urine could be effective within 2 days after ingestion of A. exitialis because amatoxins in 0-2 d urine accounted for more than 90% of the total urine excretion.

Highly sensitive determination of dialkyl phosphinate acids in environmental samples by ion chromatography tandem mass spectrometry.

Dialkyl phosphinate acids (DPAs) are the hydrolysates of aluminum dialkyl phosphinates (ADPs), one class of emerging phosphorus flame retardants since brominated flame retardants have been gradually phased out in recent years. It has been found that once dissolved in water, ADPs are completely hydrolyzed and exist as DPAs. However, there is no report on the determination of DPAs in environmental water samples. For the first time, we developed a method for the analysis of trace DPAs and ADPs in different environmental samples, including waters, soils and sediments. In this proposed method, MAX cartridges were employed for the purification, and ion chromatography (IC) tandem mass spectrometry (MS) method with large volume injection (200µL) and postcolumn addition of methanol and NH3·H2O were employed for the determination of DPAs and ADPs. The matrix effects were <16% for water samples and <25% for soil/sediment samples, which were greatly improved in comparison to the liquid chromatography (LC) tandem MS determination. Determined at three fortified levels of 0.02µg/L, 0.2µg/L and 1.0µg/L, the mean recoveries were from 75.8% to 110.2%, with an acceptable coefficient of variation (3.3-20%, n=6) for water samples. The limits of the method were 3.5-9.3ng/L for DPAs in environmental water samples, and 0.06-0.09µg/kg for DPAs and ADPs in soil and sediment samples. For soil and sediment samples, results determined by the present IC-MS method were in good agreement with that determined by LC-MS in our previous study.