High throughput and very specific screening of anabolic-androgenic steroid adulterants in healthy foods based on stable isotope labelling and flow injection analysis-tandem mass spectrometry with simultaneous monitoring proton adduct ions and chloride adduct ions.

In this work, a stable isotope labelling-flow injection analysis-tandem mass spectrometry (SIL-FIA-MS/MS) with simultaneous monitoring [M+H]+ and [M+Cl]- method was developed for very specific and high throughput screening of anabolic-androgenic steroids (AAS) illegally added to healthy foods. Initially, a simple centrifugation step was carried out for liquid samples, and for solid samples, a solid-liquid extraction step was conducted. Afterwards, batch chemical derivatization was carried out. After adding a certain amount of 13C6-3-NPH labelled AAS standards as the internal standards, it can be directly transferred for FIA-MS/MS analysis based on the no MS response characteristics of 3-NPH. The 3-NPH labelled AAS showed dual-polarity property, observing chloride adduct ion ([M+Cl]-) in negative ion mode and proton adduct ion ([M+H]+) in positive ion mode. The average time cost for pretreatment of each sample was less than 1 min by carrying out batch processing. The subsequent FIA-MS/MS detection enabled rapid and high throughput detection. The addition of 13C6-3-NPH-labelled AAS as internal standards can correct the matrix effect to achieve accurate quantitative analysis. The detection sensitivity was also improved by 2-5 folds after 3-NPH labelling. The limits of detection (LODs) in positive MRM mode were in ranges of 0.1-0.3 ng/mL. The validated method with simultaneous monitoring [M+H]+ and [M+Cl]- was validated in the range of 6.0-1000 ng/mL with the linear coefficient (R2) greater than 0.997. Satisfactory recoveries were found to be in ranges of 93.0-108.7%. The intra-day and inter-day RSDs were in the range of 3.5-9.9% and 5.1-14.1%, respectively. No changes in detection sensitivity of the mass spectrometry and no carry-over effects were found after numerous consecutive injections of AAS derivates. Compared with previously reported methods, the proposed method proved accurate, very specific, high throughput with good sensitivity.

Comparative life cycle assessment of biochar-based lignocellulosic biohydrogen production: Sustainability analysis and strategy optimization.

Lignocellulose has been considered a potential feedstock for biohydrogen production. Recently, a novel closed-loop concept of biochar approach was developed for enhanced lignocellulosic biohydrogen production. This study therefore targets to analyze the environmental impacts of the three existing lignocellulosic biohydrogen production processes, and evaluate the environmental performance of applying biochar in each process at this early stage of technological development. The results suggest that biochar dosing shows better environmental performance for all impact categories, especially in the consolidate bioprocessing case. Electricity consumption was found to be the dominant cause of environmental impact over the life cycle, while by-products generation was also found to have an effect on the life-cycle impacts. Future research focuses on the biohydrogen production scale, the electricity generation scheme transition towards renewable and cleaner energetic systems, and recovery the by-products to the maximum extent, that will make lignocellulosic biohydrogen production more environmentally sustainable.