RESUMO
Label selection is a critical factor for improving the sensitivity of lateral flow assay. Time-resolved fluorescent nanobeads, fluorescent submicrospheres, quantum dots, and colloidal gold-based lateral flow assay (TRFN-LFA, FM-LFA, QD-LFA, and CG-LFA) were first systematically compared for the quantitative detection of ractopamine in swine urine based on competitive format. The limits of detection (LOD) of TRFN-LFA, FM-LFA, QD-LFA, and CG-LFA were 7.2, 14.7, 23.6, and 40.1pg/mL in swine urine samples, respectively. The sensitivity of TRFN-LFA was highest. In the quantitative determination of ractopamine (RAC) in swine urine samples, TRFN-LFA exhibited a wide linear range of 5pg/mL to 2500pg/mL with a reliable coefficient of correlation (R2=0.9803). Relatively narrow linear ranges of 10-500pg/mL (FM-LFA) and 25-2500pg/mL (QD-LFA and CG-LFA) were acquired. Approximately 0.005µg of anti-RAC poly antibody (pAb) was used in each TRFN-LFA test strip, whereas 0.02, 0.054, and 0.15µg of pAb were used in each of the FM-LFA, QD-LFA, and CG-LFA test strips, respectively. In addition, TRFN-LFA required the least RAC-BSA antigens and exhibited the shortest detection time compared with the other lateral flow assays. Analysis of the RAC in swine urine samples showed that the result of TRFN-LFA was consistent with that of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and a commercial enzyme-linked immunosorbent assay (ELISA) kit.
Assuntos
Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Coloide de Ouro/química , Substâncias de Crescimento/urina , Fenetilaminas/urina , Pontos Quânticos/química , Animais , Técnicas Biossensoriais/instrumentação , Ensaio de Imunoadsorção Enzimática , Fluorescência , Imunoensaio/instrumentação , Imunoensaio/métodos , Limite de Detecção , Pontos Quânticos/ultraestrutura , Fitas Reagentes/análise , Suínos , Espectrometria de Massas em TandemRESUMO
An unusual aromadendrane-type sesquiterpenoid with a rare hemiketal-containing 10/3 ring system, named vladimuliecin C (1), and one new eudesmane-type sesquiterpenoid, named vladimuliecin D (4), together with four known sesquiterpenoids, were isolated from the roots of Vladimiria muliensis. The structures of these compounds were elucidated by analysis of spectroscopic data. The absolute configuration of 1 was assigned by X-ray diffraction analysis. A possible biosynthetic process for the formation of 1 is proposed. Compound 1 showed moderate cytotoxicity against three human tumor cell lines.
