A fluorescence polarization aptasensor coupled with polymerase chain reaction and streptavidin for chloramphenicol detection
TALANTA
Authors: Ma, Pengfei; Ye, Hua; Deng, Jieying; Khan, Imran Mahmood; Yue, Lin; Wang, Zhouping
Abstract
The authors describe a fluorescence polarization (FP) aptasensor based on the polymerase chain reaction (PCR) and streptavidin as dual FP amplifiers to detect chloramphenicol residues in food. Briefly, label-free aptamer was incubated with chloramphenicol and the aptamer-chloramphenicol conjugate was used as a template. Subsequently, the FAM-labeled forward primer and biotin-labeled reverse primer were added for PCR to amplify the template and the FAM-labeled primer. The molecular weight of FAM-labeled primer increased rapidly and the corresponding FP also enhanced. Finally, with the introduction of streptavidin, the PCR products and streptavidin were combined with the biotin-streptavidin interactions, resulting in much larger molecular weight. Thus, a dual amplified FP signal was obtained. Under optimal conditions, we were able to achieve a wide linear detection range of 0.001-200 nM. In addition, the designed strategy was applied to detect chloramphenicol in honey samples with high accuracy. Moreover, the strategy can be easily extended to detect other small molecules by changing the corresponding aptamers, which provide a promising avenue for the detection of small molecules by FP.
Preparation of Molecularly Imprinted Polymer Monolith with an Analogue of Thiamphenicol and Application to Selective Solid-Phase Microextraction
FOOD ANALYTICAL METHODS
Authors: Ma, Chao; Chen, Hui; Sun, Na; Ye, Yong; Chen, Huaixia
Abstract
A molecularly imprinted polymer (MIP) monolith has been prepared and characterized. Its application to the assay of thiamphenicol in milk with high-performance liquid chromatography-photodiodes array detector was validated. The newly developed MIP monolith was produced using an analogue to thiamphenicol as the template molecule to avoid major traditional drawback associated with MIPs of residual template bleeding. The MIP monolith synthesized in a micropipette tip could be connected with syringes in different sizes simply to perform solid-phase microextraction process without any other treatment. This molecularly imprinted polymer monolith microextraction (MIPMME) method showed high selectivity and enrichment ability for thiamphenicol (TAP). Several parameters affecting MIPMME were investigated, including the flow rate, volume, pH and salt concentration of sample, the type and volume of washing solution, and the type and flow rate of eluent. The recovery of this method for TAP was investigated and high recoveries of 93.5 similar to 96.8% from milk were obtained with relative standard deviations less than 6.3%.