A bulit-in self-calibration ratiometric self-powered photoelectrochemical sensor for high-precision and sensitive detection of microcystin-RR.

A novel high-precision aptasensor of microcystin-RR (MC-RR) is developed based on a ratiometric self-powered photoelectrochemical platform. In detail, the defective MoS 2 /Ti 3 C 2 nanocomposite with good photoelectric activity was designed to serve as the photoanode of the sensor for enhancing the signal and improving the detection sensitivity. In order to effectively eliminate external interferences, the key point of this ratiometric device is the introduction of the spatial-resolved technique, which includes the detection section and the reference section, generating reference signals and response signals, respectively. Moreover, output power was used as the detection signal, instead of the traditional photocurrent or photovoltage. Further, potassium persulfate was introduced as electron acceptor, which was beneficial for improving the electron transport efficiency, hindering electron-hole recombination, and significantly promoting the performance of the sensor. Finally, aptamer was adopted as recognition element to capture MC-RR molecules. The prepared sensor had a linear range from 10 -12  to 10 -6 M, and the detection limit was 5.6 × 10 -13 M (S/N = 3). It has good precision, selectivity, and sensitivity, which shows great prospects in the on-site accurate analysis of samples with high energy output in the self-powered sensing field.