RÉSUMÉ
A liquid chromatography-tandem mass spectrometry(LC-MS/MS)method was developed for determination of three kinds of β-agonists(Clenbuterol(CL),Ractopamine(RAC)and Salbutamol(SAL))residues in animal liver samples.The liver sample homogenates were extracted with organic solvent,followed by clean-up using the automatic magnetic solid-phase extraction(MSPE),and then analyzed using LC-MS/MS.The results showed that the magnetic mixed-mode cation exchange adsorbent(M-MCX)exhibited 34%higher adsorption capacity than the conventional mixed-mode cation exchange(MCX)column.Furthermore,the clean-up was conducted by using an automatic MSPE device,and 8 samples could be simultaneously treated within 30 min.The limits of detection(LOD)were 0.01-0.1 μg/kg,the average recoveries ranged from 88.2%to 110.5%,and the relative standard deviations(RSDs)were in range of 2.9%-10.3%at three spiked levels for the three kinds of β-agonists.Compared with the traditional SPE technique,the present method had many advantages such as simple operation,rapidity and high efficiency,which was suitable for high-throughput and automatic detection of residues in routine analysis.
RÉSUMÉ
A rapid and sensitive method for analyzing trace β-blockers in complex biological samples,which involved magnetic solid-phase extraction(MSPE)coupled with Fourier transform ion cyclotron reso-nance mass spectrometry(FTICR-MS),was developed.Novel nanosilver-functionalized magnetic nano-particles with an interlayer of poly(3,4-dihydroxyphenylalanine)(polyDOPA@Ag-MNPs)were synthesized and used as MSPE adsorbents to extract trace β-blockers from biological samples.After extraction,the analytes loaded on the polyDOPA@Ag-MNPs were desorbed using an organic solvent and analyzed by FTICR-MS.The method was rapid and sensitive,with a total detection procedure of less than 10 min as well as limits of detection and quantification in the ranges of 3.5-6.8 pg/mL and 11.7-22.8 pg/mL,respectively.The accuracy of the method was also desirable,with recoveries ranging from 80.9％to 91.0％following the detection of analytes in human blood samples.All the experimental results demonstrated that the developed MSPE-FTICR-MS method was suitable for the rapid and sensitive analysis of trace β-blockers in complex biological samples.
RÉSUMÉ
An innovative sandwich-structural Fe-based metal-organic framework magnetic material(Fe3O4@SW-MIL-101-NH2)was fabricated using a facile solvothermal method.The characteristic properties of the material were investigated by field emission scanning electron microscopy,transmission electron mi-croscopy(TEM),energy-dispersive X-ray spectroscopy,Fourier transform infrared spectroscopy,X-ray powder diffraction,vibrating sample magnetometry,and Brunauer-Emmett-Teller measurements.Fe3O4@SW-MIL-101-NH2 is associated with advantages,such as robust magnetic properties,high specific surface area,and satisfactory storage stability,as well as good selective recognition ability for chlorogenic acid(CA)and its metabolites via chelation,hydrogen bonding,and π-interaction.The results of the static adsorption experiment indicated that Fe3O4@SW-MIL-101-NH2 possessed a high adsorption capacity toward CA and its isomers,cryptochlorogenic acid(CCA)and neochlorogenic acid(NCA),and the adsorption behaviors were fitted using the Langmuir adsorption isotherm model.Then,a strategy using magnetic solid-phase extraction(MSPE)and ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry(UPLC-Q-TOF MS/MS)was developed and suc-cessfully employed for the selective pre-concentration and rapid identification of CA metabolites in rat plasma,urine,and feces samples.This work presents a prospective strategy for the synthesis of magnetic adsorbents and the high-efficiency pretreatment of CA metabolites.
RÉSUMÉ
Abstract Sunset yellow (SY), allura red (AR) and fast green (FG) are frequently used in commercial food products, although they are considered to be hazardous to public health due to their toxic efficacy and high exposure risk potency. In this study, a new, rapid, and reliable method based on a magnetic solid-phase extraction (MSPE) was developed for the simultaneous determination of SY, AR, and FG. Fe3O4 modified with Elaeagnus angustifolia was used for the first time as an adsorbent (Fe3O4-EA) in MSPE. It was characterized with scanning electron microscopy, Brunauer Emmet Teller surface area analysis and X-ray diffraction. MSPE parameters were optimized in terms of pH, adsorption, and elution time and elution volume. High-performance liquid chromatography was used for dye quantitation. Analytical separation was performed by applying ammonium acetate buffer, acetonitrile, and methanol as the mobile phase to a C18 reverse-phase analytical column. Intraday and inter-day repeatability of the method performed at the concentration of 0.2, 1.0 and 2.0 µg/mL exhibited <8.1% RSD (n=3). The limit of detection values was between 0.05-0.1 µg/mL. The adsorption data of SY, AR and FG on Fe3O4-EA were fitted with the Langmuir model with qmax values of 45.0, 70.4 and 73.0 mg/g, respectively.
RÉSUMÉ
The aim of this study is a present of a simple solvothermal synthesis approach to preparation of Cu-based magnetic metal organic framework (MMOF) and subsequently its application as sorbent for ultrasound assisted magnetic solid phase extraction (UAMSPE) of ampicillin (AMP) from cow milk samples prior to high performance liquid chromatography-Ultraviolet (HPLC-UV) determination. Characteristics of pre-pared MMOF were fully investigated by different techniques which showed the exclusive properties of proposed sorbent in terms of proper functionality, desirable magnetic property and also high specific surface area. Different influential factors on extraction recovery including sorbent dosage, ultrasonic time, washing solvent volume and eluent solvent volume were assessed using central composite design (CCD) based response surface methodology (RSM) as an operative and powerful optimization tool. This is the first report for determination of AMP using MMOF. The proposed method addressed some drawbacks of other methods and sorbents for determination of AMP. The presented method decreases the extraction time (4 min) and also enhances adsorption capacity (250 mg/g). Moreover, the magnetic property of presented sorbent (15 emu/g) accelerates the extraction process which does not need filtration, centrifuge and precipitation procedures. Under the optimized conditions, the proposed method is applicable for linear range of 1.0-5000.0μg/L with detection limit of 0.29μg/L, satisfactory recoveries (≥95.0％) and acceptable repeatability (RSD less than 4.0％). The present study indicates highly promising perspectives of MMOF for highly effective analysis of AMP in complicated matrices.
RÉSUMÉ
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.