RESUMEN
Exploiting adsorbents with highly efficient extraction performance is of great promise for extracting small organic molecules from biological samples. In this work, a novel Zn2+ -immobilized chitosan@silica hybrid monolith was prepared through a simple self-assembly Zn2+ -immobilization process. Exploited as an adsorbent in solid-phase micro-extraction for extracting trace ß-agonists, the monolith exhibited high extraction efficiencies for salbutamol, clenbuterol, and ractopamine with the enrichment factors approaching 120, 85, and 52, respectively. These could be attributed to the effective interaction between Zn2+ ions and the target molecule via coordination or other intermolecular interactions. Under optimized extraction operations, a sensitive determination was successfully developed coupling with high-performance liquid chromatography-ultraviolet detection. The linear range was 0.17-58.8, 0.12-68.5, and 0.18-65.5 ng/ml for salbutamol, clenbuterol, and ractopamine. The limits of detection of the ß-agonists were from 0.04 to 0.07 ng/ml, and the limits of quantification were from 0.12 to 0.18 ng/ml. The recoveries of spiking in mutton samples were observed in the range of 85.9%-95.7%, with relative standard deviations <8.0% (n = 3). Application tests demonstrated this newly developed determination was practical, accurate, and convenient for detecting trace content ß-agonists in meat.
Asunto(s)
Clenbuterol , Dióxido de Silicio , Extracción en Fase Sólida , Cromatografía Líquida de Alta Presión , Albuterol , ZincRESUMEN
Ionic liquid bonded polysiloxanes (PILs) are a class of polysiloxanes whose side chains contain ionic liquid (IL) moieties. They not only inherit the character of "dual nature" from ILs but also inherit the excellent film-forming ability and thermal stability from polysiloxanes. In this paper, the solvation parameter model is introduced to investigate the interaction characteristics of PILs. The experimental results show that the b values of PILs occur in a wider range than those previously reported for the stationary phases. The hydrogen bond acidity can be effectively adjusted by varying the ionic liquid content or substituents. Hindering the formation of the hydrogen-bonded networks and increasing the exposed hydrogens may be intrinsic to the strong hydrogen bond acidity of PILs. Subsequently, the separation performances of these PIL stationary phases were demonstrated by separating various mixed samples of aromatic isomers, dichloroanilines, substituted alkanes, alcohols, esters, etc. The results show that the PILs with strong hydrogen bond acidity have excellent selectivity performances for aromatic position isomers, alcohols, and substituted alkanes. This study is significant for understanding the hydrogen bond acidity and broadening the range of hydrogen bond acidity of ionic liquid stationary phases.
Asunto(s)
Líquidos Iónicos , Alcanos , Cromatografía de Gases , Enlace de Hidrógeno , SiloxanosRESUMEN
A facile in-tube solid phase microextraction (in-tube SPME) procedure was developed to enrich ractopamine before HPLC-UV analysis. This was achieved by employing amide groups modified polysaccharide-silica hybrid monolith as an efficient sorbent. The monolith was synthesized by a simple reaction with agarose oxide and tetramethoxylisane, followed by the modification of amide groups via subsequent ring opening, "thiol-ene" click and dehydration reactions. Under the optimized extraction conditions, the enrichment factors for ractopamine, dopamine, clenbuterol, para-methylphenol and phenol were determined to be 50.5, 32.2, 4.8, 2.1 and 1.8, respectively. The monolithic column has ideal selectivity for ractopamine. Coupled with HPLC-UV, this method demonstrated a linearity within 2.0-800 ng/g for ractopamine with spiking in pork muscles (R2 = 0.9958). The LOD was 0.64 ng/g (S/N = 3) and recoveries ranged from 85.2 to 108.1% (n = 3). This approach provides a feasible way for analysis of trace ractopamine in biological samples.
Asunto(s)
Cromatografía Líquida de Alta Presión , Análisis de los Alimentos/métodos , Músculos/química , Fenetilaminas/análisis , Carne de Cerdo/análisis , Dióxido de Silicio/química , Microextracción en Fase Sólida , Amidas/química , Animales , Fenetilaminas/aislamiento & purificación , PorcinosRESUMEN
Inspired by the special reducing capability of ascorbic acid (AA), ascorbic acid 2-phosphate (AA2P) has been extensively utilized as a substrate in current alkaline phosphatase (ALP) activity assays owing to the ALP-triggered transformation of AA2P into AA. However, such assays usually require AA-related complicated and laborious synthesis and/or signal generation procedures. Herein, we report an interesting in situ fluorogenic interaction between o-phenylenediamine (OPD) and AA, which inspires us to put forward a novel and simple AA2P/OPD-participated fluorescence turn-on ALP activity assay for the first time, and then the corresponding ALP-based fluorescence enzyme-linked immunosorbent assay (ELISA) has also been developed by means of the conventional ELISA platforms. According to the convenient and facile detection process with clear response mechanism, our fluorogenic reaction-based assay exhibits good sensitivity, selectivity, and excellent sensing performance, which ensures fluorescence ELISA to potentially be applied in clinical diagnosis by employing a well-studied biomarker of hepatocellular carcinoma, α-fetoprotein (AFP) as the model analyte. Such original ELISA via in situ formation of fluorophore from scratch gives a new sight to develop other potential immunoassay platforms in early clinical diagnosis by controlling the target antigens in the near future.
Asunto(s)
Fosfatasa Alcalina/análisis , Ácido Ascórbico/química , Carcinoma Hepatocelular/diagnóstico por imagen , Ensayo de Inmunoadsorción Enzimática , Fluorescencia , Colorantes Fluorescentes/química , Neoplasias Hepáticas/diagnóstico por imagen , Fenilendiaminas/química , Fosfatasa Alcalina/metabolismo , Ácido Ascórbico/metabolismo , Carcinoma Hepatocelular/metabolismo , Colorantes Fluorescentes/metabolismo , Humanos , Neoplasias Hepáticas/metabolismo , Estructura Molecular , Fenilendiaminas/metabolismoRESUMEN
A new material for solid-phase extraction of Pb(II) was prepared using chemically functionalized silica gel with alizarin violet. This material is stable in 6molL(-1) of HCl, 6molL(-1) of H(2)SO(4), common organic solvents and pH 1.0-9.0 aqueous solutions. The influences of analytical parameters including pH of the aqueous solution, amount of the functionalized silica gel, stirring time and flow rates of sample solutions on the quantitative recoveries of Pb(II) were investigated. At the optimum conditions, Pb(II) can be adsorbed with almost 100.0% retention, the adsorption equilibration for Pb(II) was achieved within 15min, and the adsorption capacity of the sorbent for Pb(II) is 3.45mgg(-1) of dry functionalized silica gel. For Pb(II) solution of 10ngmL(-1), the pre-concentration factor is as high as 500, and the recovery is higher than 92%. The new solid-phase extractant has been used for the pre-concentration of low level of Pb(II) in water and soil samples with high recoveries. The standard reference water sample (GSBZ 50009-88(2)) was introduced for accuracy and precision of analytical data.
Asunto(s)
Antraquinonas/química , Contaminantes Ambientales/aislamiento & purificación , Plomo/aislamiento & purificación , Dióxido de Silicio/química , Concentración de Iones de Hidrógeno , Gel de Sílice , Espectrofotometría InfrarrojaRESUMEN
A new selective solid phase extractor was prepared from silica gel modified with xylenol orange (SGMXO). The solid phase extractor is stable in 6molL(-1) HCl, common organic solvents, and pH 1.0-9.0 buffer solutions. In the batch experiments, Hg(II) can be adsorbed on SGMXO at pH 1.0 with 90.0% retention, whereas the retention of other common coexisting metal ions such as Cd(II), Pb(II), Cu(II), Ni(II), Co(II), Mn(II), Zn(II), and Fe(III) is less than 4.1%.. The adsorption equilibration for Hg(II) was achieved within 3min. At optimum conditions, the adsorption capacity of the extractor is 18.26micromolg(-1) of dry modified silica gel, and the preconcentration factor is as high as 333. The recovery is still higher than 95% for the preconcentration of 10ngmL(-1) Hg(II). The new solid phase extractor has been used for the preconcentration of low level of Hg(II) in surface water, tap water in chemistry laboratory and student's dormitory and a simulated sea water samples, recoveries of 98.2-100.6% were obtained. It is showed that low level of Hg(II) can be effectively preconcentrated by this new selective solid phase extractor.