RESUMO
A simple,rapid and sensitive upconversion immunochromatographic assay(UICA) was developed to detect imidaclothiz using NaYF4:Yb,Er upconversion nanoparticles(UCNPs) labeled with anti-imidaclothiz monoclonal antibody. The amino-modified UCNPs were conjugated with anti-imidaclothiz monoclonal antibody to prepare the UICA strip,which could realize the quantitative detection of imidaclothiz using a fluorescence photometer with an external 980 nm laser source. The working conditions of the UICA were systematically optimized, and the sensitivity, specificity, precision and accuracy were assessed by the studies of cross-reactivity (CR), spiked recovery and validation with HPLC. Under the optimal conditions (pH 8. 0, 0.3 mol/L NaCl,2.5% methanol and 0.2% PEG2000), the UICA could be completed in 25 min for the detection of imidaclothiz. The half-maximal inhibition concentration (IC50), limit of detection (IC10) and linear range (IC10-IC90) were 97.37 ng/mL,26.30 ng/mL and 26.30-363.08 ng/mL, respectively. The UICA had no CR with the analogues of imidaclothiz except for imidacloprid. The average spiked recoveries were 71.8%-97.2% with the relative standard deviations of 0.7%-10.7% in the matrices of paddy water, soil,pear,peach,wheat,cucumber,tomato and rice. The detection results of UICA for the authentic paddy water and pear samples were consistent with that of high performance liquid chromatography (HPLC).
RESUMO
An enhanced gold immunochromatographic assay ( GICA ) with simplicity, rapidity and high sensitivity was developed to detect imidaclothiz by using the high affinity between biotin and streptavidin. The 13-nm AuNPs were double-labeled with anti-imidaclothiz antibody and biotinylated DNA, and the 41-nm AuNPs were labeled with streptavidin to prepare an enhanced gold immunochromatographic test strip for imidaclothiz. The working conditions of the strip were systematically optimized, and the sensitivity, specificity, precision and accuracy were assessed by testing the cross-reactivity ( CR) , spiked recovery and validation with high performance liquid chromatography ( HPLC) . Under the optimal conditions, the detection could be completed in 10 min with visual result, and the limit of detection ( LOD ) was 25 ng/mL. The analysis showed no cross-reactivity with analogues of imidaclothiz except for imidacloprid. The detection results of GICA agreed with the spiked concentrations of imidaclothiz at spiked levels of 0 . 05 , 0 . 5 and 5 μg/g in river water, rice, cucumber, tomato, pear, cabbage and apple samples. The detection results of GICA for imidaclothiz in unknown concentration river water and pear samples were consistent with that of HPLC.
RESUMO
A molecularly imprinted polymer (MIP) for the selective solid phase extraction of imidacloprid, imidaclothiz, thiacloprid was synthesized by polymerization for 24 h using thiacloprid as template. Dynamic adsorption and selective adsorption test showed that the MIP could quickly adsorb the imidacloprid, imidaclothiz, thiacloprid, with good selectivity for targets. The maximum static adsorption capacity of MIP was 31. 7, 36. 7 and 45. 3 mg / g, respectively. A molecularly imprinted solid phase extraction (MIP-SPE) was developed to separate, clean up and enrich the thiacloprid, imidacloprid and imidaclothiz residue in paddy water, soil, rice, tomato, cucumber. The average recoveries were 80. 2% -98. 8% , with relative standard deviation of 1. 4% -4. 5% . The MIP-SPE was used to analyses the real samples, the result was satisfied.