Dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography–flame ionization detection (GC-FID), as a simple, rapid and efficient method, was developed for the determination of amitraz in honey sa...Dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography–flame ionization detection (GC-FID), as a simple, rapid and efficient method, was developed for the determination of amitraz in honey samples. This method involves the use of an appropriate mixture of the extraction and disperser solvents for the formation of a cloudy solution in 5.0 mL aqueous sample containing amitraz. After extraction, phase separation was performed by centrifugation and the concentrated amitraz in the sedimented phase was determined by gas chromatography—flame ionization detection (GC-FID). Some important parameters such as the type and volume of extraction and disperser solvents, and the effect of pH and salt on the extraction recovery of amitraz were investigated. Under the optimum conditions (13 μL of carbon tetrachloride as an extraction solvent, 1 mL of acetonitrile as a disperser solvent, no salt addition and pH 6) preconcentration factor and the extraction recovery were 955 and 95.5%, respectively. The linear range was 0.01 - 1.0 mg?kg–1 and the limit of detection was 0.0015 mg?kg–1. The relative standard deviation (RSD, n = 4) for 0.1 mg?kg–1 of amitraz was 3.2%. The recoveries of amitraz from honey samples at the spiking levels of 0.1 mg?kg-1 were 78.8 and 98.2%. The results indicated that DLLME is an efficient technique for the extraction of amitraz in honey samples.展开更多
As an effective and universal acaricide, amitraz is widely used on beehives against varroasis caused by the mite Varroa jacobsoni. Its residues in honey pose a great danger to human health. In this study, a sensitive,...As an effective and universal acaricide, amitraz is widely used on beehives against varroasis caused by the mite Varroa jacobsoni. Its residues in honey pose a great danger to human health. In this study, a sensitive, rapid, and environmentally friendly surface-enhanced Raman spectroscopy method (SERS) was developed for the determination of trace amount of amitraz in honey with the use of silver nanorod (AgNR) array substrate. The AgNR array substrate fabricated by an oblique angle deposition technique exhibited an excellent SERS activity with an enhancement factor of -10^7. Density function theory was employed to assign the characteristic peak of amitraz. The detection of amitraz was further explored and amitraz in honey at concentrations as low as 0.08 mg/kg can be identified. Specifically, partial least square regression analysis was employed to correlate the SERS spectra in full-wavelength with Camitraz to afford a multiple-quantitative amitraz predicting model. Preliminary results show that the predicted concentrations of amitraz in honey samples are in good agreement with their real concentrations. Compared with the conventional univariate quantitative model based on single peak’s intensity, the proposed multiple-quantitative predicting model integrates all the characteristic peaks of amitraz, thus offering an improved detecting accuracy and anti-interference ability.展开更多
Intra-abdominal injection of amitraz(0.25 nmol per honeybee,i.e.,approx 2.3 nmol/g)to emerging worker bees,in vivo,led to a significant hypertrehalosemia(300-400%)followed by a hyperglucosemia(≈600%).Maxima were reac...Intra-abdominal injection of amitraz(0.25 nmol per honeybee,i.e.,approx 2.3 nmol/g)to emerging worker bees,in vivo,led to a significant hypertrehalosemia(300-400%)followed by a hyperglucosemia(≈600%).Maxima were reached at 0.5 and 2h,respectively.A strong negative correlation between glucosemia and trehalosemia appeared after injection of pure phentolamine (1 nmol per bee),suggesting stimulation of trehalase activities.Simultaneous administration of the α-blocker at≥0.25 nmol per individual suppressed the hyperglycemic response of amitraz. The formamidine pesticide thus likely acts on the honeybee α-aminergic system.1989 Academic Press,Inc.展开更多
The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decrease...The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decreases were observed at 30-45 min with 0.25 nmols per bee, for phospholipids, fatty acids, steroids and triacylglycerols. However increases were observed either later or with higher doses. The decreasing action observed with 0.25 nmol AMZ per bee was inhibited by simultaneous injections of the a antagonist phentolamine (from 0.25 to 2.0 nmols per bee). The toxicity of AMZ to honeybees thus likely involves the mobilization of lipids from the gut, via action of this formamidine pesticide on a-adrenoceptors.展开更多
文摘Dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography–flame ionization detection (GC-FID), as a simple, rapid and efficient method, was developed for the determination of amitraz in honey samples. This method involves the use of an appropriate mixture of the extraction and disperser solvents for the formation of a cloudy solution in 5.0 mL aqueous sample containing amitraz. After extraction, phase separation was performed by centrifugation and the concentrated amitraz in the sedimented phase was determined by gas chromatography—flame ionization detection (GC-FID). Some important parameters such as the type and volume of extraction and disperser solvents, and the effect of pH and salt on the extraction recovery of amitraz were investigated. Under the optimum conditions (13 μL of carbon tetrachloride as an extraction solvent, 1 mL of acetonitrile as a disperser solvent, no salt addition and pH 6) preconcentration factor and the extraction recovery were 955 and 95.5%, respectively. The linear range was 0.01 - 1.0 mg?kg–1 and the limit of detection was 0.0015 mg?kg–1. The relative standard deviation (RSD, n = 4) for 0.1 mg?kg–1 of amitraz was 3.2%. The recoveries of amitraz from honey samples at the spiking levels of 0.1 mg?kg-1 were 78.8 and 98.2%. The results indicated that DLLME is an efficient technique for the extraction of amitraz in honey samples.
基金supported by the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province (No.16KJB510009 and No.17KJB510017)Jiangsu Province Natural Science Foundation of China (BK20150228)
文摘As an effective and universal acaricide, amitraz is widely used on beehives against varroasis caused by the mite Varroa jacobsoni. Its residues in honey pose a great danger to human health. In this study, a sensitive, rapid, and environmentally friendly surface-enhanced Raman spectroscopy method (SERS) was developed for the determination of trace amount of amitraz in honey with the use of silver nanorod (AgNR) array substrate. The AgNR array substrate fabricated by an oblique angle deposition technique exhibited an excellent SERS activity with an enhancement factor of -10^7. Density function theory was employed to assign the characteristic peak of amitraz. The detection of amitraz was further explored and amitraz in honey at concentrations as low as 0.08 mg/kg can be identified. Specifically, partial least square regression analysis was employed to correlate the SERS spectra in full-wavelength with Camitraz to afford a multiple-quantitative amitraz predicting model. Preliminary results show that the predicted concentrations of amitraz in honey samples are in good agreement with their real concentrations. Compared with the conventional univariate quantitative model based on single peak’s intensity, the proposed multiple-quantitative predicting model integrates all the characteristic peaks of amitraz, thus offering an improved detecting accuracy and anti-interference ability.
文摘Intra-abdominal injection of amitraz(0.25 nmol per honeybee,i.e.,approx 2.3 nmol/g)to emerging worker bees,in vivo,led to a significant hypertrehalosemia(300-400%)followed by a hyperglucosemia(≈600%).Maxima were reached at 0.5 and 2h,respectively.A strong negative correlation between glucosemia and trehalosemia appeared after injection of pure phentolamine (1 nmol per bee),suggesting stimulation of trehalase activities.Simultaneous administration of the α-blocker at≥0.25 nmol per individual suppressed the hyperglycemic response of amitraz. The formamidine pesticide thus likely acts on the honeybee α-aminergic system.1989 Academic Press,Inc.
文摘The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decreases were observed at 30-45 min with 0.25 nmols per bee, for phospholipids, fatty acids, steroids and triacylglycerols. However increases were observed either later or with higher doses. The decreasing action observed with 0.25 nmol AMZ per bee was inhibited by simultaneous injections of the a antagonist phentolamine (from 0.25 to 2.0 nmols per bee). The toxicity of AMZ to honeybees thus likely involves the mobilization of lipids from the gut, via action of this formamidine pesticide on a-adrenoceptors.
