Quantitative detection of malachite green in sediment by a time-resolved immunofluorescence method combined with a portable 3D printing equipment platform.

Rapid detection technology of aquaculture fishery drug residues is needed to supplement large-scale instrument methods. To do this, the time-resolved fluorescence immunoassay (TRFIA) method and portable three-dimensional (3D) printing equipment platform were used, in combination with smartphones, to detect malachite green (MG) in pond sediments. The TRFIA was coupled to MG monoclonal antibodies (mAb) through lanthanide metal microspheres europium (Eu3+). The labeled antibody produced competitive immunity in the immune reaction system, and the specific fluorescence intensity in the product was determined by a portable 3D printing equipment platform to achieve quantitative analysis. To test this method, leucomalachite green (LMG) was converted to MG by oxidation of dicyanoquinone (DDQ), and a qualitative analysis was achieved. Methodological evaluation results were satisfactory, recoveries were 83 %-104 %, the limit of detection (LOD) was 0.3 ng/g, the limit of quantitation (LOQ) was 0.7 ng/g, and the coefficient of variation was 1.3 %-7.3 %. The linear equation y = -0.1496x + 0.5585 was in the range of 0-10 ng/g. The linear regression correlation coefficient was 99.2 %. The TRFIA was confirmed and positive samples were measured. Results were consistent with the standard method, which demonstrated that the TRFIA was feasible and that the detection results were reliable. Compared with the national standard method, the TRFIA saves time, is more convenient, and has high sensitivity. It provides an efficient technical method for the rapid screening of MG in the sediments of aquaculture environments.

Quantitative detection on different HBsAg levels by chemiluminescence immunoassay and time-resolved immunofluorescence assay / 中国感染控制杂志

Objective To evaluate the accuracy and feasibility of time-resolved immunofluorometric assay (TRI FA) for detection of HBsAg based on Abbott automated chemiluminescence immunoassay(CMIA),so as to carry out this project in primary hospitals,and provide reference for individual antiviral strategy and prediction of therapeutic effect.Methods Serum of 157 patients infected with hepatitis B virus were detected with CMIA and TRIFA,specimens with HBsAg titers exceeding the detection limit were firstly diluted,then performed quantitative analysis.HBsAg levels were divided into 4 groups:≤100 IU/mL,101-1 000 IU/mL,1 001-20 000 IU/mL,and ＞ 20 000 IU/mL,quantitative correlation between two methods was analyzed.Results The linear regression equation of two methods was Y=2.323X-896.3,correlation coefficent r=0.943,P＜0.001.CMIA was as a reference,4 groups were divided for analysis,results showed that when detected specimens was at low concentration of HBsAg,TRIFA value was low compared with CMIA method,while detected specimens was at high concentration of HB sAg,CMIA value was high,two reagents had good consistency in the detection of different concentrations of HBsAg(both P＜0.05),when concentration was at 1 001-20 000 IU/mL,consistency was the best.Conclusion The accuracy of two reagents in the quantitative detection of HBsAg is similar,and the best correlation of detection value is 1 000-20 000 IU/mL.TRIFA assay has wide application for its low-cost and easy to be operated,which is especially suitable for primary hospitals.