Nutritional of assessment school lunches for primary and secondary school students in the Pearl River Delta / 中国学校卫生

Objective@#To investigate nutritional quality of school lunch in some primary schools and middle schools in the Pearl River Delta, and to provide the scientific basis for improving the nutritional quality of students lunch and formulating scientific and effective interventions.@*Methods@#Five-day lunch meal survey by chemical analysis were conducted, and students lunch at school were recorded by meal review in three age groups from 8 primary and middle schools in the Pear River Delat area. The energy and nutrient content were obtained and compared with the reference intake of dietary nutrients of student.@*Results@#The average protein intake at lunch of all age groups had reached the recommended standard (80%-95%), the energy supply ratio of carbohydrate in the range of 38.3%-42.3%, the energy supply ratio of fat in 63% school meal exceeded the recommended standard. Vitamin A, vitamin B 1, vitamin B 2, calcium, iron and other nutrients were seriously inadequate; while sodium intake far exceeded the recommended standard.@*Conclusion@#The main nutrients of school lunch of primary and middle school in Pearl River Delta can basically meet the growth and development needs, but there are still some deficiency and unbalanced diet nutrient content which are lower than the recommended intake. It is recommended to strengthen nutrition education of catering enterprises and school to improve the scientific combination of diets.

Carboxylated graphene oxide/polyvinyl chloride as solid-phase extraction sorbent combined with ion chromatography for the determination of sulfonamides in cosmetics.

A carboxylated graphene oxide/polyvinyl chloride (CGO/PVC) material was prepared as a sorbent for the selective extraction of sulphonamides from complex sample. After being dispersed in buffer solution, sample was transferred into the prefabricated solid-phase extraction (SPE) column, which integrated extraction and cleanup into one single-step. A multi-response optimization based on the Box-Behnken design was used to optimize factors affecting extraction efficiency. Compared with the commonly commercial sorbents including MCX, WCX and C18, CGO/PVC hybrid material had higher extraction selectivity and capacity to sulphonamides. The limits of detection and quantification for seven target compounds were in the range of 3.4-7.1 µg/L and 11.4-23.7 µg/L, respectively. The self-assembly SPE cartridge was successfully used to enrich seven analytes in anti-acne cosmetics prior to ion chromatography detection with good recoveries of 87.8-102.0% and relative standard deviations of 1.2-6.4%, implying that this method was suitable for routine analysis of cosmetics.

A strategy for improving the sensitivity of molecularly imprinted electrochemical sensors based on catalytic copper deposition.

A novel method to improve the sensitivity of molecularly imprinted polymer sensors was developed. Oxytetracycline (OTC), which was selected as the template molecule, was first rebound to the imprinted cavities. Gold nanoparticles were then labeled with the amino groups of OTC molecules via electrostatic adsorption and non-covalent interactions. Copper ions were catalytically reduced by the gold nanoparticles, and copper was deposited onto the electrode. The deposited copper was electrochemically dissolved, and its oxidative currents were recorded by differential pulse voltammetry (DPV). OTC could be determined indirectly within the concentration range of 3.0×10(-10) to 1.5×10(-7)mol L(-1) with a detection limit of 6.8×10(-11)mol L(-1).