ABSTRACT
Background & objectives: Avian influenza (AI) viruses have been a major cause of public health concern. Wild migratory birds and contaminated environmental sources such as waterbodies soiled with bird droppings play a significant role in the transmission of AI viruses. The objective of the present study was to develop a sensitive and user-friendly method for the concentration and detection of AI viruses from environmental water sources. Methods: Municipal potable water, surface water from reservoirs and sea were spiked with low pathogenic AI viruses. To concentrate the viruses by precipitation, a combination of potassium aluminium sulphate with milk powder was used. Real-time reverse transcription-polymerase chain reaction was performed for virus detection, and the results were compared with a virus concentration method using erythrocytes. Drinking water specimens from poultry markets were also tested for the presence of AI viruses. Results: A minimum of 101.0 EID50(50% egg infectious dose)/ml spiked H5N1 and 101.7 EID50/ml spiked H9N2 viruses were detected from spiked potable water; 101.0 and 102.0 EID50/ml spiked H5N1 virus was detected from surface water and seawater samples, respectively. The present method was more sensitive than the erythrocyte-binding method as approximately 10-fold higher infectious virus titres were obtained. AI H9N2 viruses were detected and isolated from water from local poultry markets, using this method. Interpretation & conclusions: Viability and recovery of the spiked viruses were not affected by precipitation. The present method may be suitable for the detection of AI viruses from different environmental water sources and can also be applied during outbreak investigations.
ABSTRACT
The environmental organic pollutant of di-2-ethylhexy phthalate ( DEHP ) was analyzed by extractive electrospray ionization mass spectrometry ( EESI-MS ). Effect of some important experimental conditions were investigated systematically, including the electrospray voltage, temperature of ion-transport tube, sample injection rate and extractant composition. Under the optimal conditions, a method for rapid detection of DEHP in water sample was established. DEHP levels in different samples with complex matrixes were measured, including landfill leachate, urban sewage and lake water. The results showed that DEHP in water samples could be ionized by EESI source and obtained the molecule ion (m/ z 391. 28) at the positive detection mode, and then CID experiment were performed to obtain the secondary fragment ions m/ z 279. 26, 167. 12 and 149. 11. The intensity of characteristic peak m/ z 149. 11 possessed a good linearity with the concentration of DEHP in the range of 5-1000 μg / L with the correlation coefficient of R2 = 0. 9991, and the detection limit (LOD) of 0. 21 μg / L. The recoveries of DEHP at three spiked levels (8, 80, 400 μg / L) were 96. 2％ - 111. 2％ , with RSDs of 5. 6％ - 11. 8％ . With the developed EESI-MS method, the concentrations of DEHP in landfill leachate, urban sewage and Yan lake water were 556. 5, 275. 3 and 37. 8 μg / L, respectively. The EESI-MS method possessed many advantages such as no requirement of sample pretreatment, fast analysis speed ( about 3 min per sample), simple operation and high sensitivity, thus providing a new mass spectrometric method for rapid detection of phthalate esters.
ABSTRACT
Fe3O4-grafted nitrogen-doped graphene (Fe3O4/N-G) nanomaterials were synthesized by chemical co-precipitation method, and its adsorption properties were discussed preliminarily.It was demonstrated that the adsorption of parachlormetaxylenol on Fe3O4/N-G was not limited to uniform monolayer adsorption and the adsorption kinetic followed the pseudo-second-order kinetic mode.Then, an ultrasound-assisted magnetic solid-phase extraction with Fe3O4/N-G as the magnetic adsorbent has been developed for the determination of four compounds including triclosan, chloroxylenol, hexachlorobenzene and 2,2′,4,4′,5,5′-hexachlorobiphenyl in environmental water samples, in combination with gas chromatography coupled to tandem mass spectrometry.Several factors related to extraction efficiencies, such as the amount of adsorbent, extraction time, sample pH and desorption conditions were investigated.The proposed preparation procedure was as follows: 6.0 mg of Fe3O4/N-G was dispersed into 100 mL of water sample under ultrasound.After 15 s, the Fe3O4/N-G carrying four compounds was separated from the water sample by an external magnetic field.Then, the targets were eluted from Fe3O4/N-G with 3 mL of ethanol and 2 mL of dichloromethane, sequentially.Finally, the eluent was dried under a mild stream of nitrogen and reconstituted with methanol and dichloromethane (1∶1, V/V) for the subsequent GC-MS/MS analysis.Under the optimized condition, an excellent linearity was observed in the range of 0.1-10 ng/L for the four compounds, with the correlation coefficients ranging from 0.9983 to 0.9999.The limits of detections (S/N=3) ranged from 0.05 to 0.6 ng/L and the limits of quantity (S/N=10) ranged from 0.2 to 2.4 ng/L.The mean recoveries at three spiked levels ranged from 68.2% to 99.6%.The relative standard deviations (RSDs) of intraday and interday were in the range of 3.3%-6.9% and 3.4%-9.4% (n=6), respectively.The proposed method was demonstrated to be simple and feasible for the trace analysis of antimicrobial agents and organochlorine contaminants in environmental water samples.
ABSTRACT
Objective To establish a continuous flow analytical method for determination of potassium in environmental water sample.Methods The concentration of patassium in environmental water sample was determined by ALLIANCE auto-matic analyzer,and its data were compared with the data obtained from atomic absorption spectrophotometry.Results The de-tection limit of this method was0.5?g /ml.The method revealed linear relationship at the potassium concentrations of5-1000?g /ml.The recovery rate of standard addition method ranged from to97%to102%.The relative standard deviations were0.82%-1.23%.Conclusion The contents of potassium in environmental water samples could be accurately and rapidly deter-mined by continuous flow analysis.