ABSTRACT
@#A sandwiched electrochemical immunoassay based on the AuNPs@GSH-CdTe as a signal label, which formed by GSH-CdTe QDs and AuNPs, with dual signal amplified by reduced graphene oxide and AuNPs was proposed for the sensitive detection of prostate specific antigen(PSA). Through a sandwich immunoreaction, the target PSA and AuNPs@GSH-CdTe labeled Ab1 were captured to rGO/AuNPs-Ab2 surface. After the HNO3-dissolution step, square wave stripping voltammetry(SWSV)analysis of the captured CdTe QDs was used to quantify the concentration of PSA. In this system, AuNPs possessedlarge specific surface and good biocompatibility, which could effectively expand the amount of antigen and GSH-CdTe QDs loading and signals amplifying, while rGO played a synergistic amplification role due to its large specific surface. The proposed method showed good linearity ranging from 0. 5 to 200 ng/mL with the detection limits of 5. 0 pg/mL. It also showed excellent selectivity, good reproducibility, satisfactory stability. In addition, the method was successfully applied to the determination of real samples. The result was satisfactory and the recovery could fall in 98. 20%- 106. 2%, which represented a novel approach for versatile detection of tumor markers.
ABSTRACT
OBJECTIVE:To establish the method for rapid determination of nuezhenoside in Salvia miltiorrhiza.METHODS:The contents of salvianolic acid B,rosmarinic acid,lithospermic acid and tanshinone (tanshinone Ⅱ A+tanshinone Ⅰ +cryptotanshinone) were determined by HPLC (as reference value).Quantitative model for the contents of above components was established by partial least square (PLS)-NIR spectra.According to the reference value,143 samples were collected and the spectrum was pretreated by first-order derivative.The optimal range of wave band for salvianolic acid B,rosmarinic acid,oxalic acid and tanshinone were 6 773.98-3 981.12,6 670.85-3 996.54,8 544.66-3 936.28,8 188.06-3 875.31 cm-1.RESULTS:The methodology for the content determination of salvianolic acid B,rosmarinic acid,oxalic acid and tanshinone were in line with the requirement.The coefficient (R2) of internal cross validation for quantitative correction model of salvianolic acid B,rosmarinic acid,oxalic acid and tanshinone were 0.919 0,0.832 2,0.821 5,0.925 6.The deviation of corrected mean square roots were 4.46,0.48,1.34,0.71,respectively.The R2 values of external validation were 0.852 6,0.957 3,0.819 3,0.953 1,respectively;and mean square root of prediction error (RMSEP)were 9.77,0.28,0.94,0.63,respectively.CONCLUSIONS:The method is rapid,accurate,simple and pollution-free,and can be used for rapid determination of multi-maker ingredients in S.miltiorrhiza.