同时测定葡萄果实中56种矿质元素的电热板消解-ICP/MS法的建立

采用电热板消解进行样品前处理,建立电感耦合等离子体质谱(ICP-MS)法同时检测葡萄果实中56种矿质元素的方法.在优化电子控温加热板的消解条件和仪器测定条件下,各元素的检出限为0.002 ng/g(Na)～32.89 ng/g(Se).各元素的相对标准偏差(RSD)均小于5%;各元素的加标回收率在80.79%(Al)～110.0%(Ga)之间,表明该方法具有灵敏、准确、可靠的特点,能够满足多元素同时分析的要求.应用该方法对赤霞珠、美乐和霞多丽成熟果实矿质元素进行测定,结果表明,在3个品种的葡萄果实中均可检测到56种矿质元素,其中矿质元素B,Mn,56Fe,As,Cd,Sb,稀土元素(Y,La,Ce,Pr,Nd,Tb) 和Tl,Th,U的含量在品种间具有显著差异.     

微波消解技术在农业样品分析中的应用

利用光纤压力自控密闭微波消解系统对土壤和植株样品中重金属元素测定的影响进行了研究，确立了样品消解试剂、微波消解每件及样品预处理方法。结果表明，该方法与常压湿法消解相比，具有样品消解时间短、消解试剂用量少、样品污染小等特点，是准确可靠的土壤及植株样品中重金属元素检测样品消解处理方法。     

ICP-OES测定三种方法消解土壤中重金属含量的研究

采用电热板消解、全自动石墨消解、微波消解三种不同的消解方法对四种土壤标准样品进行前处理消解,使用电感耦合等离子体发射光谱仪(ICP-OES)测定其中Pb、Cu、Zn、Ni、Cr五种重金属的含量,并对三种消解方法效果进行对比。结果表明,在检出限方面,三种方法均达到要求,微波消解检出限最低。在精密性上,三种方法的五种元素的相对标准偏差均小于10%。在准确性方面,电热板消解后Pb的测定出现个别值不在标准值范围。     

ICP-OES测定金矿尾矿区优势植物中的重金属元素

研究了3种消解方法对测定金矿尾矿区优势植物中多种重金属元素的消解效果。采用电热板敞开消解、高压罐密闭消解和微波消解对秭归月亮包金矿尾矿区节节草、五节芒和蜈蚣草3种优势植物进行前处理,ICP-OES测定Cr,M n,Zn,Cu,Ni,Pb,M g,Al和Fe 9种重金属元素含量,实验结果表明,3种消解方法都能满足测定要求,其中微波消解法的准确度、精密度和回收率最好;高压罐密闭消解试剂用量少、元素损失少;电热板敞开消解法波动性较大,但适于大批量样品分析。在实际分析中,应根据样品量、重金属元素含量和结果准确度等要求选择合适的消解方法。检测结果表明,矿区的优势植物五节芒、节节草和蜈蚣草具有较强的重金属耐性。     

微波消解-火焰原子吸收光谱法测定土壤中钴

土壤样品经硝酸、盐酸和氢氟酸(5+3+2)混合溶液微波消解后,用火焰原子吸收光谱法测定其钴含量.对消解体系、消解时间和消解温度的选择等进行了试验并予以优化.方法用于测定土壤样品中钴含量,加标回收率在96%～106%之间.与电热板消解法相比,经t检验,在置信水平α=0.05时,测定环境土壤标准样品,两方法无显著性差异.     

测定土壤中重金属元素的样品消解方法

探讨适用于重金属分析的土壤样品处理方法。利用原子吸收光谱法测定土壤中Cu,Mn,Ni,Pb和Zn 5种元素的含量,对电热板、微波和水浴3种消解方法进行比较,结果表明:3种样品预处理方法的检出限、准确度和精密度均满足分析检测要求。其中,电热板法样品消解较彻底,Cu和Pb的测定结果准确,但试剂、时间和人力消耗多,且为敞开式消解,高温及产生的大量酸雾危害环境与健康;微波法为密闭式消解,样品和试剂用量少,耗时短,自动化程度高,消解彻底,安全环保,Mn的测定结果准确,但成本高,不适于大批量样品分析;水浴法为半封闭式消解,简单易行,Ni和Zn的测定结果准确,但消解剂中不含氢氟酸,不适于含有大量硅酸盐样品的处理。     

微波消解-电感耦合等离子体质谱法测定土壤中10种重金属元素

利用硝酸、盐酸、氢氟酸混合液和微波消解仪密闭消解样品，建立了一种微波消解-电感耦合等离子体质谱（ICP-MS）法同时测定土壤中铜、铅、锌、锰、钒、铬、镉、镍、锡、铊10种重金属的分析方法。取0.100 0 g土壤样品于消解罐中，采用4 mL硝酸+1 mL盐酸+1 mL氢氟酸消解体系按照设定程序进行微波消解，冷却，定容后利用电感耦合等离子体质谱法进行。结果表明，以铑元素作为内标，10种重金属元素在一定的质量浓度范围内与其信号强度呈线性关系，线性相关系数均不小于0.999 8，检出限为0.010～0.92 mg/kg。对3种标准物质进行测定，测定值的相对标准偏差为2.89%～7.72%(n=10)，相对偏差为-5.95%～4.11%。该方法分析流程简单，工作效率高，检出限低，适合大批量土壤样品的多元素同时分析。     

ICP-MS法测定土壤中稀土元素的消解条件研究

本文采用"硝酸-氢氟酸-高氯酸-硫酸"的湿法消解体系,优化了各种酸的用量和消解条件,以103Rh、185Re为内标元素,采用He碰撞模式消除多原子离子对待测元素的干扰,建立了土壤中15种稀土元素ICP-MS检测的湿法消解及分析方法。在优化条件下,不同类型国家土壤标准样品中15种稀土元素的检测结果的回收率为82.3%～113%,相对标准偏差为1.5%～8.7%,方法检出限0.001～0.015mg·kg~(-1),方法测定下限0.004～0.060mg·kg~(-1),此方法可用于多种类型土壤中稀土元素的ICP-MS检测,具有普遍适用性。     

电感耦合等离子体质谱(ICP-MS)法测定农产品地土壤中铅、镉、铬消解方法的改进

采用赶酸电热板消解农产品地土壤中的重金属,电感耦合等离子体质谱(ICP-MS)法同时测定土壤中的铅、镉、铬。研究了酸体系及酸用量、赶酸电热板的升温程序,确定了最佳消解条件。通过统计50个批次土壤样品中加入的质控样,做出质控图,结果表明:各元素测定值均落在中心附近、上下警告线之内,批次内平行样品各元素相对标准偏差均小于5%。方法克服了传统的电热板消解法的缺点,弥补了高压罐消解法和微波消解法的不足,方法快速、准确,适合于大批量样品的分析。     

盐酸消解-原子荧光光谱仪测定土壤中总汞

本研究利用原子荧光光谱仪,探寻适合本实验室测定土壤总汞的方法。实验中对沸水浴消解和电热板消解这两种土壤样品的前处理方法、消解液种类以及仪器检测等因素进行条件试验,结果表明：土壤样品选用(1+1)盐酸溶液在沸水浴下加热消解、在热汞条件下分析待测液中的总汞含量是最佳样品消解及测定方法,该方法标准曲线的相关系数大于0.999,仪器最低检出限为0.006μg/g,精密度为1.2%~4.8%(n=7),样品准确度满足标准土样的要求。该方法快速简单,空白背景低,样品精密度准确度较高,适用于土壤中总汞的测定。     

化妆品中Hg、As和Pb的微波消解—氢化物发生ICP—AES法测定

采用微波消解－氢化物发生ICP－AES法测定化妆品中Hg、As和Pb,加入L－半胱氨酸消除了过渡金属离子的干扰,考察了微波消解、氢化物发生的最佳条件。建立的方法简便快速,测定Hg、As和Pb的RSD分别为0．59％、1．2％、2．4％（n=10),样品加标回收率分别为98．5％、99．3％和100．1％。该法已应用于化妆品的常规测定,得到满意的结果。     

Digestion of pretreated aspen substrates

Considerable controversy exists concerning the role lignin plays in the adsorption of cellulase enzymes on biomass. Recent studies using extracted, purified hardwood lignin have shown these materials have a propensity for cellulase adsorption; however, native lignin is carbohydrate-linked and far less condensed. In this study, we report the results of adsorption-kinetics analyses of cellulase-complex activities using five pretreated aspen substrates, including an exhaustively enzyme-hydrolyzed one. These data indicate that the polymer-binding cellulase activities are removed from solution at higher rates and extents in the presence of low lignin-content versus high lignin-content substrates. This order of adsorption was found to be essentially the inverse for beta-glucosidase adsorption.     

Microcalorimetric Monitoring of Anaerobic Digestion Processes

Microcalorimetry was used for monitoring anaerobic digestion processes of heavily polluted industrial waste waters (from cheese industry, distilleries, yeast plant). Interpreting the thermal power-time curves by HPLC, some sub-processes in batch cultures were tentatively identified as acidogenic, acetogenic and methanogenic. Processes underlying power-time curves up to 10 h were different for different wastes. In the case of cheese whey and distillery waste it was acidogenesis, in the case of sulfate containing waste - presumably reduction of sulfates. The effect of Biotreat 100 (BimKemi Eesti Ltd.), a preparation for removing H₂S from waste water, was observed for these processes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mesophilic Digestion Kinetics of Manure Slurry

Anaerobic digestion kinetics study of cow manure was performed at 35°C in bench-scale gas-lift digesters (3.78 l working volume) at eight different volatile solids (VS) loading rates in the range of 1.11–5.87 g l⁻¹ day⁻¹. The digesters produced methane at the rates of 0.44–1.18 l l⁻¹ day⁻¹, and the methane content of the biogas was found to increase with longer hydraulic retention time (HRT). Based on the experimental observations, the ultimate methane yield and the specific methane productivity were estimated to be 0.42 l CH₄ (g VS loaded)^–1 and 0.45 l CH₄ (g VS consumed)^–1, respectively. Total and dissolved chemical oxygen demand (COD) consumptions were calculated to be 59–17% and 78–43% at 24.4–4.6 days HRTs, respectively. Maximum concentration of volatile fatty acids in the effluent was observed as 0.7 g l^–1 at 4.6 days HRT, while it was below detection limit at HRTs longer than 11 days. The observed methane production rate did not compare well with the predictions of Chen and Hashimoto’s [1] and Hill’s [2] models using their recommended kinetic parameters. However, under the studied experimental conditions, the predictions of Chen and Hashimoto’s [1] model compared better to the observed data than that of Hill’s [2] model. The nonlinear regression analysis of the experimental data was performed using a derived methane production rate model, for a completely mixed anaerobic digester, involving Contois kinetics [3] with endogenous decay. The best fit values for the maximum specific growth rate (μ _m) and dimensionless kinetic parameter (K) were estimated as 0.43 day^–1 and 0.89, respectively. The experimental data were found to be within 95% confidence interval of the prediction of the derived methane production rate model with the sum of residual squared error as 0.02.     

Advance in Microwave-assisted Digestion Techniques

Since 1975 when Abu-samra first reported the use of microwave as a heat source for wet digestion methods, sample preparation techniques have ushered in a new era. Using this technique, not only has the sample matrix been decomposed completely, but also digestion times have been dramatically reduced with other benefits such as little contamination, less reagent and sample usage, reduction in loss of volatile species and low blank values. In this paper, some developments in microwave-assisted digestion (MAD) are presented.     

Non－decoloured In－gel Digestion of Coomassie Blue－stained Proteins

A simplified method is presented for tryptic digestion of Coomassie brilliant blue(CBB)-stained proteins in polyacrylamide gels. Compared with conventional methods, the proposed method does not require a re-moval of the dye before digestion, and is thus faster and saves a lot of labor. The resulted digest canbe ana-lyzed by either RPLC/ESIMS or MALDI MS for identification of the protein in a conventional way. Model studies with bovine serum albumin(BSA) showed that 50 ng of the protein could be routinely identified. The simplified procedure displays a tendency to produce more incompletely cleaved peptides, which is favorable for improving the sequence coverage.     

微波消解法测定高锰酸盐指数

高锰酸盐指数是以高锰酸钾为氧化剂 ,测得化学需氧量 ,一般仅限于地表水、饮用水、生活污水的测定[1] 。常规的高锰酸盐指数测定法需在常压下用沸水浴加热 30ｍｉｎ(从水浴重新沸腾起计时 ) [2 ] ,所需时间较长。用微波消解法测定ＣＯＤｃｒ方法已有报道[3,4 ] ,但对高锰酸盐指数测定方法未见报道。本文采用微波消解的方法对高锰酸盐指数测定方法进行改进 ,在常压下 ,用理论ＣＯＤ 5 0 0ｍｇ·Ｌ-1的葡萄糖溶液作为分析试样。通过对火力调节、微波时间、酸度等条件试验 ,建立了微波消解测定高锰酸盐指数方法。结果表明 ,微波消解具有高效、…     

米雅BM颗粒治疗消化功能紊乱62例的报告

用米雅治疗小儿消化功能紊乱６２例,取得了满意的疗效,治愈５８例,占９３％。     

厌氧消化过程化学变化的教学研究

有氧和无氧分解是生物体代谢有机物的2种途径,前者一直是生物化学课程中物质代谢的教学核心和重点。厌氧消化是有机物经无氧分解生成甲烷和二氧化碳的途径,相比于有氧分解,其具有化学反应众多、中间产物多、途径复杂等特点,同时对维护自然生态平衡、物质循环和人类社会的绿色健康发展等具有重要作用。如此重要的途径长期以来一直没有在生物化学教材与教学内容中体现,亟需进行教学改革。利用布鲁姆教学目标分类理论将厌氧消化过程中的主要反应、氧化还原过程及电子传递、热力学变化及串联反应等知识进行系统介绍,对物质代谢的另一条无氧路径进行补充,丰富了学生代谢网络的知识框架,完善了生物化学教学体系,相关教学内容和经验可供同行参考借鉴,对相关课程教学改革具有重要价值。     

Digestion of titanium bearing geologic materials involving microwaves

An environmentally friendly and rapid digestion procedure involving 10 mL of acid mixture (HNO3 : HCl : HF = 2:2:1) for 0.1 g of sample in closed vessel microwave digester following heating program : 250W for 10 min., hold time 2 min., 600 W for 17 min, and Ventilation time 10 min was developed. The operating parameters were varied and optimized by factorial design approach using "Steepest Ascent" method. The validity of the recommended digestion procedure were examined by analyzing several well characterized standard reference materials such as diabase (W2), basalt (BIR-1, JB-3, BHVO-1), granite (G2), gabbro (JGb-1), Mn-nodule (Nod-A-1, Nod-P-1), sediment (STSD-4, LKSD-2), limestone (KH-2), soil (SAu-1), ilmenite (IGS-31), rutile (IGS-32), Zircon (IGS-35) and titanium dioxide (SRM-154b) employing both inductively coupled plasma-atomic emission spectrometry (ICP-AES) and well known spectrophotometric method. An excellent agreement between the methods and the certified values of standard reference materials suggest that the digestion procedure can be used for quality control and allied purposes.