Papers by Keyword: Solid-Phase Extraction (SPE)

Abstract: HAAs content was investigated in five meat products (including roasted chicken, mutton, beef, pork, fish) using solid-phase extraction-high performance liquid chromatography ( SPE-HPLC). The linear range was between 0.05 ~ 16.0μg ·mL^-1, the detection limits (S/N=3) were in the range of 0.13 ~ 0.42ng·g^-1, and the recoveries were in the range of 63.08 ~ 105.03%, while RSD was from 1.96 ~ 8.77%.

Abstract: This study focused on using liquid Chromatography Tandem Mass Spectrometry to detect N-Nitrosodimethylamine (NDMA) at trace concentrations in water. The water sample was preconcentrated by solid-phase extraction method. To find an elution which can obtain higher recovery, three reagents with different organic solvents were examined. After comparing the recoveries and the standard deviation of the elution, finally the dichloromethane was determined as the elution of the experiment. Then the concentrated sample was analyzed by a method combining SPE pretreatment and LC separation with tandem mass spectrometry using multiple reaction monitoring (MRM).

Abstract: This work describes a routine monitoring method for simultaneous determination of three classes of veterinary antibiotics (quinolones, sulfonamides, and tetracylines) in the aquaculture water. The selected eleven pharmaceuticals include four quinolones (enoxacin, ofloxacin, ciprofloxacin and lomefloxacin), four sulfonamides (sulfadiazine, sulfadimidine, sulfamethoxazole and sulfisoxazole) and three tetracyclines (tetracycline, chlortetracycline, and doxycycline). The entire procedures for pre-concentration by solid phase extraction (SPE) using Oasis HLB, and liquid chromatography-ultraviolet spectrometry (LC-UV) quantification were examined and optimized. The chromatographic separations were performed on a Kromasil 100-C₁₈ (250 mm×4.6 mm, 5 μm) column, using 0.1% (v/v) formic acid in water and acetonitrile as mobile phase with gradient elution, and 280 nm as the detective wavelength. The recovery efficiencies were found to be 85-117% for quinolones, 81-109% for sulfonamides, and 84-110% for tetracyclines at three spiking levels (5, 10 and 50 μg/L). The developed method was applied to real water samples collected from four aquafarms located in Yichang, Hubei Province, China. Three or four tested antibiotics were detected in all water samples, with concentrations ranging from 0.65 μg/L to 4.33 μg/L. The method is convenient and rapid, and provides a quantitative measurement of multi-residue antibiotics without complex and expensive analytical equipment.

Abstract: A novel surface ion-imprinted polymer (S-IIP) has been synthesized by surface ion-imprinting concept in the presence of sodium trititanate whisker, Sr(II), chitosan and γ-Glycidoxypropyl trimethoxysilane (KH-560) for selective solid-phase extraction (SPE) of trace Co(II) from aqueous solutions. Characterizations of S-IIP were achieved by FT-IR spectra, SEM and surface area measurement. Results showed that the adsorption of cobalt(II) onto S-IIP follows pseudo-second order kinetics and could be fitted by the Langmuir isotherm with the maximum adsorption capacity Q being 8.27 mg×g^-1 at 25°C. Thermodynamic parameters including DHº, DGº and DSº were calculated and it is indicated that Co(II) adsorption on S-IIP is exothermic, spontaneous and physical adsorption reaction. Moreover, according to the dimensionless separation factor R_L (R_L<1) it indicates that it’s a highly favourable adsorption. Finally, the detection limit (3s) of 5.6 ng·mL^-1 with the relative standard deviation (RSD) for 1.0 μg×mL^-1 cobalt(II) of 1.86% (n=10) were obtained.

Abstract: Ion exchange solid phase extraction has been applied broadly in the complex sample pretreatment in recent years. This paper has introduced the basic principle, types, influence factors and operation process of ion exchange solid phase extraction, and reviewed the application of ion exchange solid phase extraction technique to residue analysis of pesticide, veterinary drug, environment and biomedical metabolites.

Abstract: In this paper, a novel microdevice-based solid phase extraction (SPE) method has been developed to extract genomic DNA from real biological samples, such as whole blood, by using a green reagent NaCl as the new binding salt. Guanidine as a bind salt was widely used for extraction DNA with a high extraction efficiency. But it was proved that guanidine was a kind of polymerase chain reaction (PCR) inhibitors, which is also toxic and the waste of guanidine might contaminate environment. NaCl is a natural, nontoxic, cheap, and green reagent, which would be a perfect candidate to replace guanidine. Silicon - polydimethylsiloxane (PDMS) - glass microdevice with a microchannel was designed and fabricated by micro electromechanical system (MEMS) technology. The DNA adsorption on the surface of the microchannel was observed by scan electron microscopy (SEM) technology. Then both NaCl and guanidine were used as the binding salt to extract genomic DNA from real biological sample. Compared with the binding salt of guanidine, the microdevice-based SPE method using NaCl is able to extract enough genomic DNA from rat whole blood in 30 min. About 725.2-1279.3 ng/mL genomic DNA was successfully extracted from whole blood by using NaCl. This highly efficient, effortless, and green method can be widely used as a lab-on-a-chip component for initial biologic sample preparation.

Abstract: A new solid phase extractant silica aerogel immobilized with Cyanex 301 {bis (2,4,4-trimethylpentyl) dithiophosphinic acid} (SAWC) was prepared via a sol-gel method and investigated for the extraction of Zn (II) from aqueous solution by a batch extraction technique. It is found that SAWC can extract about 100% zinc at equilibrium pH 1.7. Prepared SAWC was characterized by FT-IR, BET, EDX and SEM which proved the presence of Cyanex 301 into silica aerogel. Moreover, the material is also easily regenerated and reused in the subsequent removal of Zn (II) in five cycles. Therefore, it could be concluded that it may perform as a solid phase extractant in the extraction of metal ions from the aqueous solution.

Abstract: The synthesis and performance of a molecularly imprinted polymer (MIP) designed to enable the clean-up of the interferences existing in alprazolam (Alpra) drug samples is described. The MIP was synthesized using non-covalent molecularly imprinted method. Nimetazepam (Nimet), which has a similar chemical structure as the major impurities in Alpra drug samples, was used as the dummy template. Methacrylic acid was used as the monomer. Both the affinity and selectivity of the MIP for Nimet and structurally related compounds were examined through batch-rebinding studies. The specific binding amount of Nimet was determined to be 11.4 mg•g-1. The MIP was used as the sorbent in solid phase extraction (MI-SPE) and methanol was used as the washing solvent for the clean-up of Nimet in the Alpra complex samples. The effective clean-up of Nimet was achieved, with a recovery > 90% for Alpra, in the stimulated samples.

Abstract: A novel micro-extraction procedure was developed through the use of an electrospun polymer nanofiber as a solid-phase extraction (SPE) sorbent to directly extract benzimidazoles in pork. The target compound was then monitored by a high performance liquid chromatography with ultraviolet detector (HPLC-UV) system. The eluted solvent was investigated meanwhile. Under the optimized conditions, a linear response for benzimidazoles over the range of 20-1000 ng mL−1 was achieved with the γ2 >0.99. The recoveries were in the range of 95.4%~101.2%. RSDs of intra-day and inter-day assays were 3.5%~6.3% and 5.7%~9.9%. The method is simple, sensitive, accurate and repeatable, which can be used for the determination of benzimidazoles in pork.

Abstract: Chemically bonded solid phase materials are very important in separation chemistry. The chemically modified silica gel contains rest silanol groups that can affect the retention properties when they are used for separation of compounds. Some commercially available solid phase extraction (SPE) materials based on silica gel were analysed for rest silanol groups by near infrared spectroscopy. The combination frequency of the water molecules in the 5500- 5000 cm ^-1 region was used in identifying the nature of water molecules on the surface and the information was used to identify the types of silanol groups on the surface. Second derivative technique was employed in the detailed analysis. Nine different SPE materials including C18, C8, C₆H₅, NH₂, OH, CN, SiOH, SA (SCX) and SB (SAX) were examined by near infrared spectroscopy for rest silanol groups. The results show that the non-polar and polar stationary phases contain vicinal silanol groups and the ion exchange solid phase materials contain free, vicinal and geminal silanol groups.