巧克力的营养特点和作用

巧克力是一种营养素很全面的食品。因其具有较高的能量和蛋白质,丰富的人体必需微量元素,以及“多酚”这种十分有利于人体健康的植物化合物等生理特点,所以具备了有益于人体的多种保健功能,应用前景十分广泛。巧克力对人体的积极作用体现在心血管病、糖尿病、癌症、贫血、止咳等诸多方面,将有效地帮助改善一系列营养问题。     

青海湖地区植物微量元素自然背景值及其特征

分析了以青海湖区各类植被中采集的４６种主要植物样品的８种微量元素,得到了区内植物和各类植被的微量元素自然背景值。为植物微量元素学、青海湖地区生态环境研究所 、草原建设、蓄业发展以及生物地球化学找破等提供了基础资料。     

植物源性食品中多农药残留GC-MS高通量快速检测技术研究进展

植物源性食品基质复杂、农药种类繁多、农药残留限量标准严格,因此建立植物源性食品中多农药残留高通量快速检测技术十分重要。气相色谱-质谱联用（GC-MS）技术是多农药残留高通量检测领域应用最为广泛的一种技术。然而现阶段植物源性食品中多农药残留GC-MS高通量检测仍存在问题。国内外科研工作者对其进行了大量研究,在现有设备的基础上开发前处理新技术以及复杂信号高通量解析新算法是提高该检测水平的关键。该文对近年来国内外发展的基于GC-MS的植物源性食品中多农药残留高通量快速检测技术及相关文献进行了归纳和总结,重点从适合于不同种类农药提取的新型样品前处理技术、基于“数学分离”的复杂信号高通量解析新算法等方面阐述了植物源性食品中多农药残留高通量快速检测的最新进展,并对其存在的问题提出了相关建议,旨在为食品多农药残留高通量快速检测提供参考。     

农药的加工剂型

农药不仅在消灭农作物病虫草害,保证农业丰收方面发挥着巨大作用,而且对于提高农产品质量、调节植物生长、节省劳力、改革耕作制度,也逐步显示威力。农药与化肥不同,它不是农作物的“食物”,而是用量很少的“药剂”。为了达到经济、有效、安全使用的目的,就必须对农药进行加工。加工时所用的辅助剂(填料、溶剂、表面活性剂等)不单起负载和稀释作用,有时还可以提高药效。如防治仓库粮食害虫和地下害虫时,选用硬度较大的多角形载体,易划破害虫体表,增强了药剂效果;又如少量表面活性物质(湿润剂、分散助悬     

水滴在超疏水植物叶片上的沉积方法和机理研究进展

自然界中有很多超疏水植物叶片, 水滴撞击在这些表面时极易产生溅射和反弹, 造成农用化学品喷雾施药时药物的大量损失, 利用率低下, 从而重复喷洒施药. 农用化学品过度使用将造成食品安全、 农药残留、 水资源浪费及环境生态污染等问题. 因此, 增加水滴在超疏水植物叶片表面的沉积效率对提高农药利用率尤为重要. 本文从分析水滴在超疏水表面的撞击动力学特征开始, 结合添加助剂后液滴的物理化学性质, 系统阐述了水滴在超疏水植物叶片上的沉积方法和机理, 并提出筛选助剂和研究机理不仅要考虑助剂性质还要结合基底结构、 撞击动力学特征等因素, 而且还要考虑单水滴尺寸大小、 基底运动和弹性及环境因素等对沉积的影响. 本文对农药喷洒及生物医学、 机械工程、 涂料喷涂和油墨打印等领域均有指导意义和应用价值.     

农作物病害的防治与药肥合一

叙述了农作物病害的发生与必需营养元素的关系。试验证明只有在平衡作物营养元素的基础上使用农药治病，才能标本兼治，收到事半功倍的效果。文章同时叙述了补充农作物中微量元素的方式以及药肥合一的使用领域、用法与用量。     

梅州地区几种蔬菜中硒含量的初步调查

采用原子荧光光度法测定了梅州地区种植的5种农作物生菜、西洋菜、春菜、番薯叶和茶树菇中微量元素硒的含量,为人们在饮食过程中摄入适量的硒,保障人体健康提供参考。     

四种药用香薷植物中多种微量元素分析

对高原香薷、萼果香薷、密花香薷、细穗香薷等四种药用香薷植物中的17种微量元素含量进行了测定和分析。结果表明,4种香薷植物中常量元素以K含量最高,其次为Ca、Mg、Na;必需微量元素中以Cu、Fe、Mn元素的含量为高;非必需微量元素As、Hg、Pb、Cd、Sb含量较低,从重金属元素的角度考虑,使用所测定的4种香薷植物是安全的。     

推荐一种硼肥中硼含量测定方法

硼虽仅占植物干重的十万分之一至万分之一,但它在植物糖类代谢过程中起着重要作用,是农作物不可缺少的微量元素之一.缺硼时,农作物根茎于腐、籽粒干瘪,甚至停止生长或死亡.由于硼肥成份复杂,除去干扰物比较困难,因此,其测定方法往往比较繁琐、费时.本文作者结合实验工作,探索出一种简便、快速的方法,并应用于硼肥中常量硼的测     

钼与社会

钼及其合金的优异机械性能与良好的物理化学性能,使其倍受工业各部门的青睐,导致85%的钼用于制备铁基合金;钼及其含氧化合物为化学石油工业的重要催化剂;二硫化钼则被誉为“润滑之王”;钼还被用于制备无机颜料。钼在生命系统中为必须的微量元素,它能促进植物生长发育,提高农作物产量;对人类防治一些癌症也有一定作用。预计本世纪末,世界对钼将出现供不应求的趋势。     

氨基酸微肥的生产和应用研究进展

总结了国内外复合氨基酸微量元素螯合物生产工艺的研究和进展情况以及降本增效的综合利用措施,对土壤补充微量元素的重要性和方法作了阐述,并介绍了该类微肥的使用范围和效果,复合氨基酸微量元素,稀土元素螯合物具有用量少,成本低,回报率高的特点,不但能提高农作物的产量,改善品质,还能有效地起到灭菌,杀虫,除草,降低农药残留量的作用,是很有发展前途的新型肥料。     

Applications of stripping voltammetric techniques in food analysis

Stripping voltammetric techniques are powerful analytical tools that are becoming widely used in various chemical analysis fields. Hence, the objective of this survey is to give a general overview on the scope of the applicability of stripping voltammetric methods in food industries. The applications discussed include recent studies on the utilization of these electroanalytical methods in determination of food contaminants (toxic metals, pesticide, fertilizers and veterinary drugs residuals), trace essential elements, food additive dyes and other organic compounds of biological significance. Tables that give method summaries referenced to the original work are provided.     

量子点传感器在有机磷农药残留检测中的应用

有机磷农药作为一种神经毒剂,在过量使用后会造成许多潜在危害,如污染作物、环境以及使人畜中毒等。因此,建立高灵敏、高特异的有机磷农药残留检测方法对于保障食品安全与人体健康具有重要意义。基于量子点的传感器分析检测方法因其具有灵敏度高、特异性强、响应速度快、操作简单等优势,在有机磷农药残留检测方面成为研究热点与发展趋势。本文对国内外近年来量子点传感器在作物、环境以及生物样品中有机磷农药残留检测的应用进展进行了综述,并对该领域的前景进行了展望。     

Concentration Levels of Trace Elements in Carrots,Onions, and Potatoes Cultivated in Asopos Region,Central Greece

The objective of the work was to investigate the correlation between the environmental pollution of Asopos river area in Viotia, Greece and the concentration of Ni, Cr, Cd, Pb, Cu, and As in specific crops (carrots, onions, and potatoes) produced in this region. Samples of these crops from Asopos and other Greek areas (control) were collected. For method accuracy, the Certified Reference Material, CRM 281 (trace elements in rye grass) was measured. Simultaneous multi-element graphite furnace atomic absorption spectrometry was used after a microwave acid digestion. The levels of Ni in Asopos food were found up to 9 times higher than control (e.g., Asopos potatoes had an average Ni content of 800 µg/kg compared to 78 µg/kg in control, whereas Asopos carrots had an average Ni content of 474 µg/kg compared to 93 µg/kg in control). Likewise, the levels of Cr were found to be about 2 times higher than control (e.g., Asopos carrots were found to have an average Cr content of 43 µg/kg compared to 20 µg/kg in control). The levels of Cd and Pb had a high variance in the Asopos sourced food. Arsenic was not detected in any sample. Our results indicate that the mean intake of trace elements (Ni, Cr, Pb, Cd, and Cu) by adults through consumption of crops from Asopos, for an average consumption pattern, generally is well below the Allowable Daily Intakes (ADIs). Comparison was also made with data from literature from Greece.     

Assessing the transfer of pesticides to the atmosphere during and after application. Development of a multiresidue method using adsorption on Tenax and thermal desorption-GC/MS

An air sampling and analytical method based on adsorption on porous polymer (Tenax TA) followed by automatic thermal desorption (ATD) and GC/MS analysis was developed for ten pesticides commonly used on major crops in Britanny and some of their metabolites in air (from spray drift and volatilisation transfer processes): alachlor, atrazine (and two major degradation products: deethylatrazine and deisopropylatrazine), carbofuran, cyprodinil, epoxyconazole, iprodione (and 3,5-dichloroaniline), lindane (and -HCH, its isomer), metolachlor, terbuconazole and trifluralin. This method was established with special consideration for optimal thermal desorption conditions, linear ranges, limits of detection and quantification. Moreover, collection efficiencies of Tenax TA at room temperature were examined. This method was then applied to the determination of ambient pesticide levels during the spraying season at a rural area. The method was also applied to determine the vertical gradient of alachlor concentrations on a treated maize parcel to evaluate volatilisation fluxes.     

火焰原子吸收光谱法测定煤矸石土种植的农作物中金属元素含量

采用干灰化法消化样品,火焰原子吸收光谱法测定了煤矸石土种植植物中的钙、镁、铜、锌、铁、锰等6种金属元素的含量。6种元素均在一定的质量浓度范围内与其吸光度呈线性关系,方法的检出限(3s)在0.002～0.017mg.L-1之间。回收率在96.8%～106.1%之间,相对标准偏差(n=6)在0.17%～4.25%之间。方法用于煤矸石土和沙土上种植的玉米、蚕豆和豌豆中6种金属元素含量的测定,结果表明:煤矸石土上种植粮食中6种元素的含量均高于沙土上种植的,矸石土壤种植的蚕豆中镁含量较高,豌豆中铁和锰含量较高。     

软硬酸碱理论与元素的存在形式

在无机化学元素部分教学中,元素的存在形式既是该元素化学性质的重要组成部分,又决定了元素单质和化合物的制备与合成方法。运用离子的电子结构知识及化学基本原理分析元素在自然界中的存在形式,既可以加深学生对化学基本知识和基本原理的理解,又可以将元素知识形成知识链以减少记忆量。本文利用软硬酸碱理论和地球环境的基本状况来分析元素在自然界的存在形式,得到了与实际较为符合的结果,表明这是一种简单实用的思路和方法。     

Metallofluorescent indicators as spray reagents for the in situ determination of organophosphorus pesticides on thin-layer chromatograms

Fluorescence-quenched solutions of palladium(II)-calcein and palladium(II)-calcein blue are shown to be sensitive spray reagents for the detection and in situ determination of organothiophosphorus insecticides on thin-layer chromatograms. The palladium is displaced from its non-fluorescent indicator complex by the pesticide producing fluorescent spots on the plate. Visual detection limits for 16 insecticides are given. As little as 10–50 ng of phosphorodithioate pesticides can be detected within l h after spraying and drying the plate, while the detection limits for phosphorothioates are somewhat higher (ca. 50–100 ng). Quantitative measurements may be conveniently made 18–24 h after spraying and drying the plate. Plots of fluorescence (as peak area) versus quantity of pesticide are linear over a 10–15 fold range. The relative standard deviation of replicate spots of Guthion (50–400 ng) and Cygon (50–100 ng) is 4–9 % and less than 15 % for 10 ng of Cygon or 20 ng of Guthion. The method was applied to the analysis of lake water spiked with Cygon. The recovery of 2–20 μg l^-1 of the pesticide was 87–113% with no clean-up other than t.l.c. required.     

A quick analytical method using direct solid sample introduction and GC-ECD for pesticide residues analysis in crops

In this work, an analytical method for GC using direct solid sample introduction was developed to tackle the problem regarding quick detection of pesticide residue in crops and large-scale screening of samples. 10 mg of the crop solid sample without sample pre-treatment was directly introduced into a modified split/splitless injector for GC analysis. A split/splitless injector was modified to quickly remove oxygen and low boiling-point matrices of the sample. The whole sampling procedure was simple and it required less than 5 min. The experimental parameters including injector-port temperature, removal of oxygen and low boiling point matrices, size and the amount of the solid sample, oven temperature program were studied. Satisfactory recoveries of 6 pesticides (methyl parathion, fenitrothion, aldrin, dieldrin, endosulfan, o,p′-DDT) were obtained in maize and rice sample. Relative standard deviation was less than 15%. Experimental results showed that the proposed method was quick and reliable for pesticide residues analysis in crops.