Community structure and species diversity dynamics of a subtropical evergreen broad-leaved forest in China: 2005 to 2020.

Here, we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in China. We found that community structure in this forest changed over a 15-year period. Specifically, renewal and death of common species was large, with the renewal of individuals mainly concentrated within a few populations, especially those of Aidia canthioides and Cryptocarya concinna. The numbers of individual deaths for common species were concentrated in the small and mid-diameter level. The spatial distribution of community species diversity fluctuated in each monitoring period, showing a more dispersed diversity after the 15-year study period, and the coefficient of variation on quadrats increased. In 2010, the death and renewal of the community and the spatial variation of species diversity were different compared to other survey years. Extreme weather may have affected species regeneration and community stability in our subtropical monsoon evergreen broad-leaved forests. Our findings suggest that strengthening the monitoring and management of the forest community will help better understand the long- and short-term causes of dynamic fluctuations of community structure and species diversity, and reveal the factors that drive changes in community structure.

Trihalomethanes in water samples: Recent update on pretreatment and detection methods.

Trihalomethanes (THMs) are classified as volatile organic compounds, considered to be a disinfection by-product during water disinfection process. THMs have been shown to be cytotoxic, genotoxic and mutagenic, with a risk of cancer when they contact with people directly. To protect public health and monitor water quality, it is important to monitor and measure THMs in drinking water. Therefore, it is crucial to develop fast, accurate, highly sensitivity and green analysis methods of THMs in various complicated matrices. Here, this review presents an overall summary of the current state of the pretreatment and detection methods for THMs in various sample matrices since 2005. In addition to the traditionally used pretreatment methods for THMs (such as headspace extraction, microwave-assisted extraction, liquid-liquid extraction), the new-developed methods, including solid-phase extraction, QuEChERS and different microextraction methods, have been summarized. The detection methods include gas chromatography-based methods, sensors and several other approaches. Additionally, benefits and limitations of different techniques were also discussed and compared. This study is anticipated to offer fruitful insights into the further advancement and widespread applications of pretreatment and detection technologies for THMs as well as for related substances.

A Review on Recent Innovations of Pretreatment and Analysis Methods for Sulfonylurea Herbicides.

Sulfonylurea herbicides (SUHs) are widely used in agriculture because of their low dosage, low cost, and high selectivity. However, due to improper use and lack of effective management, their residues pose a threat to the human health through environment and food pollution. Therefore, there is a need for simple, quick, economical, and effective methods to analyze SUHs in plant-derived foods, crops, and environmental samples. The present article presents a comprehensive review of the pretreatment and analytical technologies used for SUHs in various sample matrices, focusing on the developments since 2010. The main pretreatment methods include liquid-liquid extraction, solid-phase extraction, QuEChERS, and different microextraction methods, whereas analytical methods mainly include liquid chromatography coupled with different detectors, capillary electrophoresis, among others. In addition, the present study also compared the advantages and disadvantages of the methods and the future development is prospected.

HIGHLIGHTProgress in pretreatment and analytical methods of sulfonylurea herbicides are summarized.Pros and cons of the pretreatment and determination methods have been given.Novel materials in solid-phase extraction and solid-phase microextraction are depicted.

Capsaicinoids in Food: An Update on Pretreatment and Analysis Methods since 2010.

Capsaicinoids, whose basic chemical structure is the vanilla amide of n-nonanoic acid, are responsible for chili pepper fruits' spicy flavor (pungency) and multiple pharmacological actions. Capsaicinoids are widely used to produce intense flavor food additives due to their sensory attributes of pungency, aroma, and color. To ensure strict quality control for capsaicinoids and maximize their positive effects, valid and sensitive pretreatment and determination methods are urgently needed. Consequently, this review provides a comprehensive summary of capsaicinoids' preparation and analytical technologies in food samples. Pretreatment techniques mainly include liquid-liquid extraction, solid-phase extraction, solid-phase microextraction, and dispersive solid-phase microextraction, among others. Detection methods include liquid chromatography coupled with different detectors, gas chromatography, electrochemical sensor methods, capillary electrophoresis, etc. Furthermore, the advantages and disadvantages of various pretreatment and analytical methods are compared and discussed. Thus, the present paper has attempted to shed light on novel and traditionalpretreatment methods and determination approaches and provided proper comments about their new developments and applications.