Determination of 4-Hexylresorcinol in Shrimp Samples by Solid Phase Extraction Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry.

A method for the rapid determination of 4-hexylresorcinol (4-HR) residue in shrimp by solid phase extraction (SPE) ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established. 4-HR was extracted twice with methanol, and the extract was formulated into methanol-water solution (1:1). After being cleaned up and concentrated by a PRIME HLB solid phase extraction column, the sample was analyzed by UPLC-MS/MS and quantitatively determined by an external standard method. The separation was performed with a gradient system consisting of water and acetonitrile as the mobile phase. Monitoring was performed by electrospray ionization (ESI) in negative ion mode using multiple ion reaction monitoring (MRM). Good linearity was obtained in the concentration range of 1.0⁻100.0 µg/L, with correlation coefficients larger than 0.999. The limit of detection (LOD) was 0.25 µg/kg and the limit of quantification (LOQ) was 0.80 µg/kg. The average recoveries of 4-HR at spiked concentrations of 2.40, 6.40 and 16 µg/kg ranged from 81.35% to 94.68% with the relative standard deviations (n = 6) from 3.57% to 6.86%. The results showed that the method is simple, fast, sensitive, reliable, and reproducible; thus, it could be used as a rapid confirmation and quantitative analysis method of 4-HR residue in aquatic products.

Estimation of the psychoactive substances consumption within 12 wastewater treatment plants service areas in a certain city of Guangxi, China applying wastewater-based epidemiology.

The abuse of psychoactive substances has been increasing dramatically over the last few years, which is becoming a concern for human health and social stability. How to accurately estimate psychoactive substances' total consumption in certain areas is the key to manage such substances. In order to control psychoactive substances, 8 psychoactive substances' consumption within 12 wastewater treatment plants (WWTPs) service areas in a certain city of Guangxi, China was investigated in 2019. Firstly, a solid-phase extraction-liquid chromatography-tandem mass spectrometry method was used to determine the influent concentrations. Morphine (MOR), 3, 4-methylenedioxymethamphetamine (MDMA), methamphetamine (METH), ketamine (KET), and norketamine (NK) were detected, with the concentrations ranging from less than method detection limit (NK, MDMA) to 170.91 (METH) ng/L. Then, the back-estimation of consumption was conducted according to the objective and near real-time wastewater-based epidemiology (WBE). The results demonstrate that KET, MOR, and METH are the most abused psychoactive substances, with the mean consumption of 682.42, 167.81, and 44.56 mg/day/1000 inh, respectively. The psychoactive substance residues of WWTPs influent were analyzed to estimate such substances' consumption in specific areas, so as to provide support for risk prevention and control.

Ultrasound-assisted extraction of hesperidin from Penggan (Citrus reticulata) peel.

Hesperidin, an abundant and inexpensive bioflavonoid in Penggan (Citrus reticulata) peel, has been reported to possess a wide range of pharmacological properties. Ultrasonic extraction is an effective technique for the isolation of bioactive compounds from vegetable materials. In this study, the application of ultrasonic method was shown to be more efficient in extracting hesperidin from Penggan (C. reticulata) peel than the classical method. The effects of main ultrasonic-assisted extraction conditions on extraction yields of hesperidin from Penggan (C. reticulata) peel were evaluated, including extraction solvents, solvent volume, temperature, extraction time, ultrasonic power, ultrasonic frequency. Results showed that solvent, frequency and processing temperature were the most important factors for improving the extracting yields of hesperidin. When performed at the same temperature under the same time using three frequencies, methanol as the solvent improved the extraction yield evidently compared with ethanol or isopropanol; by comparison of the frequency influence, the yield of hesperidin was higher at 60 kHz than at 20 kHz and 100 kHz. The optimum ultrasonic conditions were determined as: methanol, frequency of 60 kHz, extraction time of 60 min, and temperature of 40 degrees C. In addition, the ultrasonic power had a weak effect on the yields of hesperidin within the experimental range. Extending ultrasonic treatment times did not result in degradation of hesperidin; the rotary beaker for materials can increase the yields of hesperidin.

Response surface methodology for the optimization of beta-lactoglobulin nano-liposomes.

Response surface methodology based on a central composite rotatable design has been successfully used to model and optimize biochemical and biotechnological processes. Heat treatment could have an effect on beta-lactoglobulin (ß-Lg) and lead to allergic reaction. To reduce this phenomenon, liposomes were used as carriers in this research. The mass ratio of phosphatidylcholine and cholesterol (2.5-12.5), ß-Lg concentration (2.5-12.5 mg mL(-1)), sonication time (5-25, min) and temperature (25-40 °C) were selected as independent variables with encapsulation efficiency as a dependent variable. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Applying a desirability function method the optimum parameters were: phosphatidylcholine to cholesterol ratio of 8.05, ß-Lg concentration of 9.09 mg mL(-1), sonication time of 17.71 min and temperature of 30 °C. The particle size and encapsulation efficiency were found to be 189 nm and 61.55%, respectively. Furthermore, the in vitro stability of ß-Lg nano-liposomes in simulated gastrointestinal juice was evaluated. The nano-liposomes showed an acceptable stability in simulated gastrointestinal juice at 37 °C for 4 h.