Rapid qualitative and quantitative analysis of trace aconitum phytotoxin by SERS.

The dual functions of phytotoxin, such as aconitine, with biological activity and toxicity ignited the related food poisoning intentionally or accidentally from time to time. The fast and accurate qualitative analysis is a prerequisite for tracking the source of poisoning and taking correct treatments. Taking the single molecule level sensitivity and molecular fingerprinting of Surface-enhanced Raman spectroscopy (SERS), we developed a highly sensitive and accurate strategy for the trace detection of three structurally similar aconitines (ATs) (aconitine, mesaconitine and hypoaconitine) by employing the 100 nm Ag NPs colloid as the SERS substrate. It was figured out that the lowest detectable concentration is in the level of 5.0 µg/L for these three ATs with the linear range of 5.0-100.0 µg/L. The qualitative and quantitative analysis of trace ATs spiked in various food samples was realized in 3 mins, which demonstrated the SERS based strategy is very promising towards the fast and on-site detection of ATs in the field of food safety or criminal identification.

Adaptive harmony search algorithm utilizing differential evolution and opposition-based learning.

An adaptive harmony search algorithm utilizing differential evolution and opposition-based learning (AHS-DE-OBL) is proposed to overcome the drawbacks of the harmony search (HS) algorithm, such as its low fine-tuning ability, slow convergence speed, and easily falling into a local optimum. In AHS-DE-OBL, three main innovative strategies are adopted. First, inspired by the differential evolution algorithm, the differential harmonies in the population are used to randomly perturb individuals to improve the fine-tuning ability. Then, the search domain is adaptively adjusted to accelerate the algorithm convergence. Finally, an opposition-based learning strategy is introduced to prevent the algorithm from falling into a local optimum. The experimental results show that the proposed algorithm has a better global search ability and faster convergence speed than other selected improved harmony search algorithms and selected metaheuristic approaches.