Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Más filtros













Base de datos
Intervalo de año de publicación
1.
Phys Rev Lett ; 131(15): 150601, 2023 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-37897783

RESUMEN

We report new Gaussian boson sampling experiments with pseudo-photon-number-resolving detection, which register up to 255 photon-click events. We consider partial photon distinguishability and develop a more complete model for the characterization of the noisy Gaussian boson sampling. In the quantum computational advantage regime, we use Bayesian tests and correlation function analysis to validate the samples against all current classical spoofing mockups. Estimating with the best classical algorithms to date, generating a single ideal sample from the same distribution on the supercomputer Frontier would take ∼600 yr using exact methods, whereas our quantum computer, Jiǔzhang 3.0, takes only 1.27 µs to produce a sample. Generating the hardest sample from the experiment using an exact algorithm would take Frontier∼3.1×10^{10} yr.

2.
Environ Res ; 237(Pt 1): 116892, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37598848

RESUMEN

Wastewater treatment plants (WWTPs) are the major sources of contaminants discharged into downstream water bodies. Profiling the contaminants in effluent of WWTPs is crucial to assess the potential eco-risks toward downstream organisms. To this end, this study investigated the contaminants in effluent of 10 WWTPs locating in 10 cities of Yangtze River delta region of China by suspected screening analysis. Further, the persistence, bioaccumulation, toxicity (PBT) and the characteristics sub-structures of PBT-like chemicals were analyzed. Totally, 704 chemicals including 155 chemical products, 31 food additives, 52 natural substances, 112 personal care products, 123 pesticides, 192 pharmaceuticals, 17 hormones and 22 others were found. The results of PBT analysis suggested that 42 chemicals (5.97% among the detected chemicals in WWTPs) were with PBT property. Among them, 31 contaminants were not reported previously. 9 characteristics sub-structures (N-methyleneisobutylamine, 1-naphthaldehyde, 2,3,3-trimethylcyclohexene, cyclohexanol, N-sec-butyl-n-propylamine, (5E)-2,6-dimethylocta-1,5-diene, 2-ethylphenol, pentadecane and 6-methoxyhexane) were found for PBT-like chemicals. The sub-structures of highly linear alkyl partially explained the significantly higher PBT score for personal care products. Present study provides fundamental information on PBT properties of contaminants in effluent of WWTPs, which will benefit to prioritize contaminants with high concerns in effluent of WWTPs.

3.
Phys Rev Lett ; 130(19): 190601, 2023 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-37243651

RESUMEN

Gaussian boson sampling (GBS) is not only a feasible protocol for demonstrating quantum computational advantage, but also mathematically associated with certain graph-related and quantum chemistry problems. In particular, it is proposed that the generated samples from the GBS could be harnessed to enhance the classical stochastic algorithms in searching some graph features. Here, we use Jiǔzhang, a noisy intermediate-scale quantum computer, to solve graph problems. The samples are generated from a 144-mode fully connected photonic processor, with photon click up to 80 in the quantum computational advantage regime. We investigate the open question of whether the GBS enhancement over the classical stochastic algorithms persists-and how it scales-with an increasing system size on noisy quantum devices in the computationally interesting regime. We experimentally observe the presence of GBS enhancement with a large photon-click number and a robustness of the enhancement under certain noise. Our work is a step toward testing real-world problems using the existing noisy intermediate-scale quantum computers and hopes to stimulate the development of more efficient classical and quantum-inspired algorithms.

4.
Phys Rev Lett ; 130(7): 070801, 2023 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-36867807

RESUMEN

Quantum metrology employs quantum resources to enhance the measurement sensitivity beyond that can be achieved classically. While multiphoton entangled N00N states can in principle beat the shot-noise limit and reach the Heisenberg limit, high N00N states are difficult to prepare and fragile to photon loss which hinders them from reaching unconditional quantum metrological advantages. Here, we combine the idea of unconventional nonlinear interferometers and stimulated emission of squeezed light, previously developed for the photonic quantum computer Jiuzhang, to propose and realize a new scheme that achieves a scalable, unconditional, and robust quantum metrological advantage. We observe a 5.8(1)-fold enhancement above the shot-noise limit in the Fisher information extracted per photon, without discounting for photon loss and imperfections, which outperforms ideal 5-N00N states. The Heisenberg-limited scaling, the robustness to external photon loss, and the ease-of-use of our method make it applicable in practical quantum metrology at a low photon flux regime.

5.
Water Res ; 235: 119895, 2023 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-36989798

RESUMEN

Biotransformation of emerging contaminants (ECs) is of importance in various natural and engineered systems to eliminate the adverse effects of ECs toward organisms. In wastewater, structurally similar ECs may transform through similar reactions triggered by common enzymes. However, the transformation pattern for them was scarcely studied. To fill the research gaps, five sulfonamides were chosen as the targeted ECs with similar structure to explore the transformation pattern in wastewater biological treatment experiments at lab scale. Through molecular networking based nontarget screening, 45 transformation products (TPs) of sulfonamides were identified and 14 of them were newly found. On the basis, five specific transformation patterns were summarized for sulfonamides by transformation pathways comparing, reaction frequency analyzing and dominant TPs comparing. Results suggested that pterin-chelation and formylation (dominant transformation pathway) and acetylation, methylation and deamination reactions were commonly occurred for sulfonamides in wastewater. Among them, the role of formylation as the dominant transformation pathway for sulfonamides transformed in wastewater was firstly reported in present study. Subsequent frontier molecular orbital calculation suggested the active site of amino (N1H2-) may contribute the specific transformation pattern of sulfonamides. Present study reveals the specific transformation pattern of sulfonamides from the aspect of TPs and transformation pathways. In the future, knowledge on the specific transformation pattern can be used to regulate and enhance the removal of a class of ECs with similar structure rather than just one of ECs.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua , Sulfonamidas , Sulfanilamida , Biotransformación , Contaminantes Químicos del Agua/química
6.
China CDC Wkly ; 4(9): 161-164, 2022 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-35356409

RESUMEN

What is already known about this topic?: Acrylamide (AA) is toxic and potentially carcinogenic and could be formed during the cooking process. It is understood that almost all foods cooked at high temperature contain AA, especially fried foods. The exposure of AA in food threatens human health. What is added by this report?: In the Sixth China Total Diet Study (TDS), AA was detected in 73.3% samples of the 12 food categories with the concentrations ranging from undetected to 176.90 µg/kg. The average dietary intake of AA was 0.175 µg/kg body weight per day and a significant decrease (45.1%) was observed compared with the Fifth China TDS. Among the 12 food categories, vegetables (59.0%), cereals (18.9%), and potatoes (10.1%) were the main contributors to AA exposure at 88.0%. What are the implications for public health practice?: This study highlighted the need to continuously monitor dietary acrylamide exposure in China, including changing food processing methods and making reasonable selection of foodstuffs in the daily diet.

7.
Wei Sheng Yan Jiu ; 50(1): 121-128, 2021 Jan.
Artículo en Chino | MEDLINE | ID: mdl-33517973

RESUMEN

OBEJECTIVE: To develop a method for the determination of 13 antibiotics in 8 classes for desinfection products by ulta-high perfomance chromatography-tandem mass spectrometry(UPLC-MS/MS). METHODS: Samples were extracted by methanol or acetonitrile. The target compouds were separated on a Waters HSS T3 column(100 mm×2. 1 mm, 1. 8 µm), and detected by triple quadrupole tandem mass spectrometer. RESULTS: The 13 selected antibiotics showed good linear relationships in the range of 4-100 µg/L and the correlation coefficients(r~2) were all above 0. 991. The limits of detection ranged from 2 to 25 µg/kg. The recovery rates at three spiked levels(low, medium and high) in three dosage forms of disinfection products were in the range of 71. 2%-130. 4%, and the relative standard deviations(RSD) were all less than 11. 3%, which could meet the detection requirements of illegal addition of antibiotics in disinfection products. Ofloxacin at a concentration of 21. 1 mg/kg was found in a cream disinfection product by the developed method, and no related drugs were detected in other samples. CONCLUSION: This method is simple, reliable, reproducible, which covers a wide range of antibiotics, and provides technical support for monitoring the illegal addition of antibiotics in disinfection products.


Asunto(s)
Antibacterianos , Espectrometría de Masas en Tándem , Cromatografía Líquida de Alta Presión , Cromatografía Liquida , Desinfección
8.
Wei Sheng Yan Jiu ; 49(2): 280-284, 2020 Mar.
Artículo en Chino | MEDLINE | ID: mdl-32290946

RESUMEN

OBJECTIVE: To develop a simple, fast and sensitive analytical method based on isotope dilution-headspace gas chromatography-mass spectrometry for the determination of 1, 4-dioxane residue in the aerosol cosmetics. METHODS: Sample was successive weighed and dissolved in 1, 3-dimehyl-2-imidazolidinone(DMI)solvent and isotope internal standard was added. Then transfered to a 20 mL headspace vial. The headspace vial was sealed and extracted 15 min by ultrasonic-assisted extraction. After separated by HP-5 MS fused silica capillary column(30 m×25 mm, 0. 25 µm), the compound was analyzed by gas chromatography-mass spectrometry in selected ion monitoring mode(GC-MS-SIM) and quantified by internal standard method. RESULTS: There were good linear correlations with R~2 no less than 0. 999 in the range of 1. 0-100 mg/kg. The limit of detection(LOD) of this method was 0. 3 mg/kg. At 0. 3, 1. 0, 5. 0 and 30 mg/kg four added concentration, recovery for five kinds of aerosol cosmetic were all between 91. 4% and 104. 2%. The relative standard deviations(RSDs) were 1. 5%-6. 3% and 1. 7%-6. 4%(n=6), respectively. CONCLUSION: The developed method has proved convenient, time-saving, accurate and sensitive and suited for determination 1, 4-dioxane in aerosol cosmetic.


Asunto(s)
Cosméticos/análisis , Aerosoles , Dioxanos , Cromatografía de Gases y Espectrometría de Masas , Espectrometría de Masas
9.
Se Pu ; 38(12): 1465-1471, 2020 Dec 08.
Artículo en Chino | MEDLINE | ID: mdl-34213262

RESUMEN

The widespread use of pharmaceutical and personal care products (PPCPs), including antipyretic and analgesic drugs, in the last two decades had led to the existence of PPCP residues in the environment, thus raising concerns about their pseudo-persistent nature and potential threat to human health. Generally, most of the detected contaminants are present at low levels (ranging from ng/L to µg/L) in environmental water. Therefore, advanced analytical methodologies are crucial to monitor the occurrence and distribution of antipyretic and analgesic drugs in environmental water. However, trace analysis of environmental pollutants is always challenging because it is necessary to extract analytes present in the sample at ultralow levels from complex environmental matrices. Therefore, an appropriate sample pretreatment is necessary to enrich the target compounds. Conventional solid-phase extraction materials show poor efficiency for the enrichment of antipyretic and analgesic drugs. We herein report a hydrophilic and lipophilic amphiphilic porous polymeric material GCHM (Guochuang hydrophilic material). GCHM was successfully prepared by a stepwise emulsification and micellization process using N-vinyl-2-pyrrolidone (NVP) and divinylbenzene (DVB) as raw materials. An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of four antipyretic and analgesic drugs in water using our solid-phase extraction (SPE) column. The water samples were extracted and purified by the GCHM solid-phase extraction column, and then analyzed by UPLC-MS/MS. Gradient elution was carried out with 0.1% formic acid aqueous solution and acetonitrile as the mobile phase. The target analytes were separated on an ACQUITY UPLC HSS T3 column (100 mm×2.1 mm, 1.8 µm), and multiple reaction monitoring (MRM) was conducted in the positive electrospray ionization mode. The isotope internal standard method was used for quantitative correction. Comparison of the enrichment efficiencies of Oasis HLB, Bond Elut Plexa, and GCHM revealed that GCHM showed the best performance. Different pH values affecting the enrichment efficiency of the GCHM SPE column were optimized, and the matrix effect was evaluated. The results showed that the four target analytes gave the best enrichment effect on the SPE column at pH 7, and the matrix effect for each substance was between 82.8% and 102.2%, indicating obvious matrix removal after the water sample was purified by the GCHM SPE column. Good correlation coefficients (r) greater than 0.995 were observed for all the target compounds in the range of 1-100 µg/L. The method limits of quantitation (S/N=10) ranged from 1 ng/L to 5 ng/L. The corrected recoveries were 85.6% to 106.4%, and the relative standard deviations (RSD) were under 5.6%. The GCHM solid-phase extraction column is inexpensive and efficient, being suitable for the detection of the four antipyretic and analgesic drugs in water. Subsequently, the occurrence of these selected antipyretic and analgesic drugs in water samples from Shanghai, Jiangsu, and Guangdong provinces were studied. The GCHM column has potential advantages over the commercial imported SPE column and is worthy of widespread application. This column can also aid the enrichment and purification of other compounds with similar structures or properties in water.


Asunto(s)
Analgésicos/análisis , Antipiréticos/análisis , Agua/análisis , China , Cromatografía Líquida de Alta Presión , Extracción en Fase Sólida , Espectrometría de Masas en Tándem
10.
Se Pu ; 35(9): 957-962, 2017 Sep 08.
Artículo en Chino | MEDLINE | ID: mdl-29048853

RESUMEN

A method was developed for the screening and detection of food poisonings by ultra high performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF MS). After extracted by acetonitrile and cleaned-up by QuEChERS, the extract was separated on a Waters Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 µm) with the gradient elution of 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in acetonitrile. TOF-MS scan-information dependent acquisition (IDA)-product ion scan was performed in positive electrospray ionization (ESI) mode to acquire high resolution MS and MS/MS spectra in one injection, and rapidly screen 581 target compounds by SCIEX OS software, including 546 pesticides, 24 mycotoxins, 11 rodenticides. The target compounds were qualitatively confirmed by mass accuracy of precursor, isotope distribution of precursor, fragment ions of precursor, and library search. Carbofuran was detected in 9 out of 11 samples with the proposed method. The retention time was further confirmed by the standard of carbofuran. The results showed the retention times were coincident between the samples and reference standard, and the deviations of accurate mass numbers were all less than 3.7×10-6. The scope of the relationship was good and the correlation coefficient was 0.998. The instrumental limit of detection (S/N=3) was 0.3 µg/kg, and the limit of quantification (S/N=10) was 1 µg/kg. The recoveries at 10, 50, 200 µg/kg levels were 75.6%-95.9%, and the RSDs (n=6) were 3.6%-6.9%. The method is rapid, simple, accurate and sensitive. It is suitable for the rapid screening and detection of public safety incidents.


Asunto(s)
Cromatografía Líquida de Alta Presión , Análisis de los Alimentos/métodos , Contaminación de Alimentos/análisis , Espectrometría de Masas en Tándem , Enfermedades Transmitidas por los Alimentos , Humanos , Micotoxinas/análisis , Plaguicidas/análisis , Rodenticidas/análisis
12.
Plant Physiol ; 169(4): 2496-512, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26471894

RESUMEN

Plastidial disproportionating enzyme1 (DPE1), an α-1,4-d-glucanotransferase, has been thought to be involved in storage starch synthesis in cereal crops. However, the precise function of DPE1 remains to be established. We present here the functional identification of DPE1 in storage starch synthesis in rice (Oryza sativa) by endosperm-specific gene overexpression and suppression. DPE1 overexpression decreased amylose content and resulted in small and tightly packed starch granules, whereas DPE1 suppression increased amylose content and formed heterogeneous-sized, spherical, and loosely packed starch granules. Chains with degree of polymerization (DP) of 6 to 10 and 23 to 38 were increased, while chains with DP of 11 to 22 were decreased in amylopectin from DPE1-overexpressing seeds. By contrast, chains with DP of 6 to 8 and 16 to 36 were decreased, while chains with DP of 9 to 15 were increased in amylopectin from DPE1-suppressed seeds. Changes in DPE1 gene expression also resulted in modifications in the thermal and pasting features of endosperm starch granules. In vitro analyses revealed that recombinant DPE1 can break down amylose into maltooligosaccharides in the presence of Glc, while it can transfer maltooligosyl groups from maltooligosaccharide to amylopectin or transfer maltooligosyl groups within and among amylopectin molecules in the absence of Glc. Moreover, a metabolic flow of maltooligosyl groups from amylose to amylopectin was clearly identifiable when comparing DPE1-overexpressing lines with DPE1-suppressed lines. These findings demonstrate that DPE1 participates substantially in starch synthesis in rice endosperm by transferring maltooligosyl groups from amylose and amylopectin to amylopectin.


Asunto(s)
Endospermo/enzimología , Sistema de la Enzima Desramificadora del Glucógeno/metabolismo , Oryza/enzimología , Almidón/metabolismo , Amilopectina/metabolismo , Amilosa/metabolismo , Metabolismo de los Hidratos de Carbono , Endospermo/genética , Expresión Génica , Sistema de la Enzima Desramificadora del Glucógeno/genética , Especificidad de Órganos , Oryza/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Semillas/enzimología , Semillas/genética
13.
Artículo en Chino | MEDLINE | ID: mdl-26887277

RESUMEN

OBJECTIVE: To establish a method for simultaneously determining the urinary concentrations of 8 carbamate pesticides. METHODS: After being purified by acetonitrile precipitation, urine samples were transferred to a liquid chromatography-tandem mass spectrometry system, and the concentrations of 8 carbamate pesticides were determined by external standard method. A C18 column was used for ultra-high-performance liquid chromatography; methanol/ammonium acetate solution was used as the mobile phase for gradient elution; the mass spectrometer was operated in a multi-reaction monitoring mode. RESULTS: The calibration curves were linear when the urinary concentrations of these carbamate pesticides were 20~800 µg/L, and the recovery rates were 61.0%~121% at spiked levels of 20, 200 and 800 µg/L, with a relative standard deviation of 1.7%~5.5%. CONCLUSION: This determination method meets the Guide for establishing occupational health standards-part 5: Determination methods of chemicals in biological materials, and can be used for simultaneous determination of 8 carbamate pesticides in the urine of poisoning patients.


Asunto(s)
Carbamatos/orina , Cromatografía Líquida de Alta Presión , Plaguicidas/orina , Espectrometría de Masas en Tándem , Calibración , Humanos
14.
Se Pu ; 32(1): 13-20, 2014 Jan.
Artículo en Chino | MEDLINE | ID: mdl-24783863

RESUMEN

A rapid method for the simultaneous screening and detection of 20 illegally added anti-diabetic chemical components in hypoglycemic and weight-reducing health foods was developed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After extracted by methanol, the sample was separated on a Poroshell 120 EC C18 column (100 mm x 2.1 mm, 2.7 microm) with the gradient elution of 5 mmol/L ammonium acetate and acetonitrile as mobile phases. The electrospray ionization (ESI) source in positive or negative ion mode was used for multiple reaction monitoring (MRM) mode. The 20 illegally added chemical components showed good linear relationships with the correlation coefficients more than 0.99. The recoveries were in the range of 75.9% - 114.0%, and the relative standard deviations (RSDs) were all not more than 11.3%. The limits of detection (LODs) were all in the range of 0.3 - 1.5 microg/L. This method is rapid, simple, sensitive, accurate and of good specificity for cracking down illegally added anti-diabetic chemical components.


Asunto(s)
Cromatografía Líquida de Alta Presión , Contaminación de Alimentos/análisis , Alimentos Orgánicos/análisis , Hipoglucemiantes/análisis , Espectrometría de Masas en Tándem
15.
Food Chem Toxicol ; 68: 290-6, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24685824

RESUMEN

Chronic fatigue accumulation increases the incidence of cardiovascular disease while the treatment of antioxidants could prevent this development. We have previously shown that quercetin-3-O-gentiobiose (QG), a flavonoid isolated from tonic herb Okra, possesses anti-oxidative properties. In the present study, the protective effects of QG were evaluated in a rat model of load-induced endurance swimming. Oral administration of QG at the doses of 25-75mg/kg could significantly improve the endurance capability of rats to fatigue along with decrease serum lactic acid and blood urea nitrogen levels were decreased. Moreover, QG could alleviate vascular impairments, enhance the activities of antioxidant enzymes and attenuate the levels of inflammatory cytokines (MCP-1, IL-6 and TNF-α). The results indicated that QG had anti-fatigue and vasoprotective effects and represented a potential agent for the treatment of aortic pathology involved with fatigue- and related syndrome.


Asunto(s)
Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/patología , Fatiga/tratamiento farmacológico , Glicósidos/farmacología , Estrés Oxidativo/efectos de los fármacos , Quercetina/análogos & derivados , Administración Oral , Animales , Antioxidantes/farmacología , Quimiocina CCL2/sangre , Interleucina-6/sangre , Masculino , Condicionamiento Físico Animal , Quercetina/farmacología , Ratas , Ratas Sprague-Dawley , Factor de Necrosis Tumoral alfa/sangre , Enfermedades Vasculares/tratamiento farmacológico , Enfermedades Vasculares/etiología , Enfermedades Vasculares/patología
16.
Eur J Pharmacol ; 730: 164-70, 2014 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-24631257

RESUMEN

Kir2.1 channel is a typical inward rectified channel with little outward currents when the membrane depolarized. Barium blocks the inward Kir2.1 currents in a voltage-dependent manner. However, in this study we found that barium would impair the rectification and open Kir2.1 outward currents at a depolarized voltage, causing increment of outward current amplitudes by 43±7% (n=5, P<0.01) after 200s barium application. In the meanwhile, a higher barium concentration did block the outward currents by 17.5±4.3% (n=4, P<0.01) and temporarily twisted current upward tendency. The increment was likely barium specific since both calcium and Kir2.1 specific blocker, Chloroethylclonidine (CEC), did not enhance the current amplitudes. The rectification of Kir2.1 was not recovered by washing barium off, which suggested a non-competitive mechanism. Since the currents occurred at phase 1, 2 of cardiac action potential, it would likely shorten the action potential plateau and it would decrease QT duration in electrocardiography (ECG).


Asunto(s)
Compuestos de Bario/farmacología , Cloruros/farmacología , Fenómenos Electrofisiológicos/efectos de los fármacos , Canales de Potasio de Rectificación Interna/genética , Canales de Potasio de Rectificación Interna/metabolismo , Células HEK293 , Humanos , Transfección
17.
Artículo en Chino | MEDLINE | ID: mdl-24630023

RESUMEN

OBJECTIVE: To establish a method for simultaneously determining the urinary concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), trans, trans-muconic acid (tt-MA), and S-phenylmercapturic acid (S-PMA) in subjects exposed to benzene. METHODS: After being purified by a solid-phase extraction column, the urine samples were transferred to a liquid chromatography-mass spectrometry system, and the concentrations of 8-OHdG, tt-MA, and S-PMA were determined by external standard method. A C18 reversed-phase column was used as the chromatographic column, and methanol/acidic ammonium formate solution was used as the mobile phase for gradient elution. The mass spectrometer was operated in a multi-reaction monitoring mode. RESULTS: For tt-MA, the calibration curves were linear in the range of 10-1000 µg/L, and the recovery rates were over 90% (relative standard deviation (RSD) < 3%) at spiked levels of 50 µg/L and 500 µg/L. For S-PMA and 8-OHdG, the calibration curves were linear in the range of 1-100 µg/L, and the recovery rates were over 85% (RSD < 5%) at spiked levels of 5 µg/L and 50 µg/L. CONCLUSION: This determination method meets the requirement of Biological materials- METHODS: of monitoring-Guide of development (WS/T 68-1996) and can be used for simultaneous determination of 8-OHdG, tt-MA, and S-PMA in urine.


Asunto(s)
Acetilcisteína/análogos & derivados , Benceno/envenenamiento , Desoxiguanosina/análogos & derivados , Exposición Profesional/prevención & control , Ácido Sórbico/análogos & derivados , 8-Hidroxi-2'-Desoxicoguanosina , Acetilcisteína/orina , Cromatografía Liquida/métodos , Desoxiguanosina/orina , Humanos , Espectrometría de Masas , Ácido Sórbico/metabolismo
18.
Artículo en Chino | MEDLINE | ID: mdl-24148959

RESUMEN

OBJECTIVE: To establish a method for determining glyphosate in the air of workplaces by ion chromatography. METHODS: Ultra-fine glass fiber filter paper was used to collect glyphosate from the workplace air. After being ultrasonically eluted with deionized water, samples were determined by ion chromatography using a conductivity detector. RESULTS: Within the range of 0.05-1.00 mg/L, a linear relationship was found with a limit of detection of 0.003 mg/m(3). The minimum detectable concentration was 0.000 41 mg/m(3) (calculated by sampling 75 L of air). For three different concentrations of glyphosate, the intra-batch relative standard deviations (RSDs) were 1.8%, 1.6%, and 0.8%, respectively, and the inter-batch RSDs were 1.9%, 2.1%, and 2.2%, respectively. The recovery rate ranged from 94.8% to 97.4%. The elution efficiency ranged from 94.5% to 96.7%. The sampling efficiency was 100%. Samples could be stored at room temperature for at least 7 days. CONCLUSION: This presented method meets the requirements of Guide for establishing occupational health standards-Part 4: Determination methods of air chemicals in workplace and is feasible for determination of glyphosate in the air of workplaces.


Asunto(s)
Contaminantes Ocupacionales del Aire/análisis , Cromatografía de Gases , Glicina/análogos & derivados , Lugar de Trabajo , Glicina/análisis , Glifosato
19.
Se Pu ; 31(7): 709-13, 2013 Jul.
Artículo en Chino | MEDLINE | ID: mdl-24164043

RESUMEN

An analytical method using HPLC-MS/MS was developed for qualitative and quantitative analysis of 23 sedative drugs in health foods. The method was based on the sonication-assisted extraction of the health food samples using 10 mL methanol. The extract was then isolated by centrifugation and the supernatant was separated on an Agilent Eclipse Plus C, column with gradient elution at a flow rate of 300 microL/min. A binary mobile phase was 10 mmol/L ammonium formate (solvent A) and acetonitrile/methanol (1:1, v/v; solvent B). The electrospray ionization (ESI) source in positive ion mode or negative ion mode was used for multiple reaction monitoring (MRM). The external standard method was used for the quantification. The calibration graphs were linear in their concentration ranges with the correlation coefficients more than 0. 990. The limits of detection (LOD, S/N= 3) were between 0. 02 - 1.0 microg/L. The recoveries for all the drugs in health foods were 82. 3% - 114. 8% with the relative standard deviations less than 14. 1% at three spiked levels. Thirteen kinds of health foods were tested, in which meprobamate and oxazepan were found in one sample separately, and zaleplon was found in two samples. The method is specific, sensitive, easy and quick and suitable for the confirmation and quantification of the 23 sedative drugs in health foods.


Asunto(s)
Residuos de Medicamentos/análisis , Contaminación de Alimentos/análisis , Alimentos Orgánicos/análisis , Hipnóticos y Sedantes/análisis , Calibración , Cromatografía Líquida de Alta Presión , Espectrometría de Masas en Tándem
20.
Se Pu ; 31(5): 473-6, 2013 May.
Artículo en Chino | MEDLINE | ID: mdl-24010349

RESUMEN

A rapid method for the simultaneous screening and detection of ten anticoagulant rodenticides in foods was developed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After the extraction by acetonitrile and clean-up by QuEChERS, the extract was separated on a Poroshell 120 EC-C18 column (100 mm x 2.1 mm, 2.7 microm) with the gradient elution of 5 mmol/L ammonium acetate and acetonitrile. The detection was carried out by UPLC-MS/MS using a negative electrospray ionization interface in multiple reaction monitoring (MRM) mode. The ten anticoagulant rodenticides showed a good linear relationship (r > 0.99) in the range of 5 - 500 microg/L. In the four samples of chili sauce, flour, vinegar and soy sauce, the spiked recoveries were in the range of 72.6% - 112%, and the relative standard deviations (RSD) were all not more than 11.2%. The limits of detection (LOD) were all in the range of 0.5 - 4.5 microg/kg. This method is rapid, simple, sensitive, accurate and of good specificity for the satisfactory rapid screening and detection of the ten anticoagulant rodenticides in the sudden public health security events.


Asunto(s)
Contaminación de Alimentos/análisis , Rodenticidas/análisis , Espectrometría de Masas en Tándem , Anticoagulantes/análisis , Cromatografía Líquida de Alta Presión
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA