铋膜电极微分电位溶出法测定酒中铅和锌

以镀铋膜电极代替汞膜电极为工作电极进行同位镀铋微分电位溶出分析，依据溶出峰值（dt/dE）与被测离子浓度成正比的关系进行定量。结果表明，在HAc—NaAc介质中，铅、锌可在镀铋膜电极上得到灵敏的微分电位溶出峰，峰电位分别为-0．55V和-1．10V，检出限铅为0、02μg／25mL，锌为0．03μg／25mL。该方法无污染，灵敏、简便，是一种快速绿色的分析方法。     

Determination of Total Sulphur Dioxide in Beer Samples by Flow‐Through Chronopotentiometry

A chronopotentiometric method for the determination of total sulphur dioxide in beer is described. Free and bound sulphites were converted to sulphite anions on alkalising the sample solutions. On acidifying the solution, the released sulphur dioxide was on‐line separated through a semipermeable membrane and transported by an electrolyte into the measuring cell and measured by stripping chronopotentiometry. The proposed method was validated and compared with the three EBC methods. The RSD of repeatability was 8.6% for the normal SO₂ level in the beer (3.4 mg/L). The results corresponded well with those obtained with the alternative EBC methods. The elaborated method was much faster and simpler than the EBC methods.     

甲烷氧化菌素-纳米金修饰金电极溶出伏安法对Cu2＋的检测

利用甲烷氧化菌素能捕捉环境中Cu2＋的特性,以及纳米金放大电信号的作用,制备甲烷氧化菌素功能化纳米金,通过将其修饰金电极的溶出伏安法对Cu2＋进行特异性检测。在优化条件下,峰电流与Cu2＋浓度的对数在10 nmol/L～100 μmol/L范围内线性关系良好,相关系数为0.960 09,检出限为1.15 nmol/L（信噪比3）。结果证明,本研究所建立的电化学新方法具有较高的检测灵敏度和稳定性,可以为未来食品中Cu2＋的检测提供一定理论依据。     

电位滴定法测定啤酒中氯离子含量

本文讨论了用银电极电位滴定法测定啤酒中氯离子含量。在20ml啤酒样品,0.5ml 6mol/LHNO_3和2.0ml 0.1g/mlKNO_3组成的体系中,测得滴定终点电位值为270±2mv。三种不同标准添加量的方法回收率都大于98.6％。方法精密度:同一样品连续测定12次,标准偏差为0.74,变异系数0.65％。同时测得三种国产啤酒中氯离子含量为114～152mg/L。     

同位镀汞阳极溶出伏安法测定牛奶中镉、铅、铜

建立阳极溶出伏安法同时快速测定牛奶中的镉、铅和铜元素的方法。利用同位镀汞阳极溶出伏安法对 牛奶样品中镉、铅和铜元素含量进行同时测定,并对测试条件进行优化。镉、铅和铜元素峰电位分别为－0.70、 －0.52、－0.08 V;线性范围分别为0.1～40、1～80、0.5～100 μg/L;检测限为0.06、0.3、0.1 μg/L。采用该方法测 定了牛奶样品中的镉、铅和铜含量,加标回收率分别为99.57%、101.3%、98.00%,相对标准偏差（n=5）分别为 4.0%、2.9%、2.7%,将测定结果与原子吸收光谱法检测结果对比,两者无显著性差异(P＞0.05）。结果表明该方法 快速、简单、准确,可用于牛奶中镉、铅和铜元素的同时检测。     

啤酒发酵过程中嘌呤含量的变化研究

研究旨在探讨啤酒酿造过程中腺嘌呤、鸟嘌呤、次黄嘌呤和黄嘌呤的含量,同时分析其与啤酒发酵常规指标的相关性。以反相离子对色谱法（RP-IPC）分析测定12批次相同浓度啤酒的嘌呤含量,利用数据分析软件spss分析嘌呤含量与啤酒发酵液常规指标的相关性。结果显示,啤酒发酵过程中,游离态嘌呤以黄嘌呤含量最高,其次是鸟嘌呤、腺嘌呤、次黄嘌呤;总嘌呤以鸟嘌呤含量最高,其次是黄嘌呤、腺嘌呤、次黄嘌呤;鸟嘌呤主要以结合态的核苷和核苷酸存在与发酵液中;无论是游离态总嘌呤含量还是总嘌呤含量均与发酵液pH值、还原糖、氨基氮、真浓极显著正相关,与酒精、发酵度极显著负相关;游离态总嘌呤含量与原浓、酵母代时极显著正相关,与酵母细胞数极显著负相关。     

电位滴定法测定大曲酸度的研究

大曲酸度是大曲的重要质量指标之一,采用传统指示剂法测定大曲酸度,受到大曲颜色干扰,误差较大。采用电位滴定法测定大曲酸度,通过大量实验数据绘图确定滴定终点pH值。该方法操作简便,提高了测定结果的准确性,用于生产过程大曲样品测定,结果令人满意。     

气相色谱法测定啤酒中的联二酮

本文介绍了采用GC-ECD分别测定啤酒中双乙酰和2,3-戊二酮的方法,文中讨论了样品制备及GC的测定条件。采用本法测定双乙酰的变异系数为2.4～5.3％,2,3-戊二酮为2.8～4.5％,添加联二酮标样的回收率良好。分别采用气相色谱法和比色法测定了25种不同啤酒样品中的联二酮含量,结果表明GC法明显优于比色法,GC法更适合作为质量控制分析用。     

微分电位溶出法直接测定食醋中铅的含量

采用微分电位溶出法对食醋中铅的含量进行直接测定,确定最佳条件为:介质采用0.1mol/L的盐酸,富集电位为-1.1 V,清洗电位为-0.05 V,电位上限-0.8 V,电位下限-0.2 V,富集时间为100 s.此法的应用测试结果令人满意.     

单克隆免疫亲和柱－高效液相色谱法测定啤酒中伏马毒素B 1、B 2

研究了单克隆免疫亲和柱－高效液相色谱法测定啤酒中伏马毒素B1、B2的方法。啤酒样品经脱气后,通过FumoniTest免疫亲和柱净化,净化液经柱前衍生,SpherisorbC18色谱柱分离,荧光检测器检测,外标法定量。对添加不同含量水平的伏马毒素B1、B2,5次重复实验的平均回收率为B186.1％～93.4％,B271.6％～82.0％。变异系数(CV)为B14.8％～7.2％,B26.3％～8.9％。检测低限为B10.005mg/kg,B20.01mg/kg。     

差示脉冲溶出伏安法测定皮蛋中铅含量

目的:建立一种快速、准确测定皮蛋中铅含量的方法。方法:采用LK98电化学微机分析系统,优化试验参数,如电解质浓度、pH值、电沉积电位以及脉冲间隔等。结果:线性范围为1×10-5￣7×10-5mg/mL,检出限为1×10-7mg/mL,RSD为3.5%。结论:该方法简便、快速、灵敏度高、重现性好、准确可靠。     

Monitoring of Beer Filtration Using Photon Correlation Spectroscopy (PCS)

In this work, different aspects of particles size distribution in filtered beer were investigated. The utilisation of commercial cellulase or protease formulations influenced significantly the stability of filtered beer. By using Photon Correlation Spectroscopy (PCS) untreated beer samples at 6 and 20°C showed good “chill” stability, while the samples treated with exogenous enzymes showed a significant modification in the particles size distribution and reduced colloidal stability. The particles size distribution in the filtrate appeared to be related to the decrease of the cut‐off size of the membrane and of the flux from the membrane. As reported, the largest particle size diameter flowing through the membrane decreased in each type of sample over the course of the filtration, due to the fouling of the filtering media. The results allowed confirmation that at the beginning of the filtration trials the main fouling cause was the decrease of the pores size within the membrane structure, more than cake formation over the membrane surface, although this second effect prevailed after a certain time.     

A Survey of Instrumentation used for the Determination of Haze in Beer

A survey has been carried out to determine the types of instruments in use within the brewing industry for the determination of haze. A questionnaire was circulated which asked users to identify and describe the instrument in use, its method of calibration and their procedures for preparation and examination of samples. The information collected was used to examine the results from respondents for haze determination on a range of beer samples in order to determine the comparative precision of each instrument type.     

动态顶空进祥分析啤酒的挥发性风味化合物

研究了采用动态顶空进样技术分析啤酒的挥发性风味化合物的方法。以高纯氮吹出并吸附于Tenax GC上的挥发性组份经加热脱附后直接注入毛细管色谱柱,将这一装置与GC-MS相连,从啤酒中检出了19种化合物,对其中的13种作了定量测定,方法具有良好的重现性和回收率。     

乳化剂OP微分电位溶出法快速测定啤酒中痕量铅的研究

探讨了乳化剂ＯＰ存在下，微分电位溶出法（ＤＰＳＡ）测定啤酒中铅的最佳条件。发现铅在含有０．１８～０．６０ｍｏｌ／ＬＨＣｌ介质中于－０．５２Ｖ（ＶＳ．ＳＣＥ）处有一灵敏的溶出峰。检出线为０．０３３μｇ／２０ｍｌ，加标回收率为９５．８％～１０２％，ＲＳＤ为１．５％～４．０％，方法已用于啤酒中铅的直接测定。     

单克隆免疫亲和柱—高效液相色谱法测定啤酒中伏马毒素B1、B2

研究了单克隆免疫亲和柱－高效液相色谱法测定啤酒中伏马毒素B1、B2的方法。啤酒样品经脱气后,通过FumoniTest免疫亲和柱净化,净化液经柱前衍生,Spherisorb C18色谱柱分离,荧光检测器检测,外标法定量。对添加不同含量水平的伏马毒素B1、B2,5次重复实验的平均回收率为B1 86．1％－93．4％,B2 71．6％－82．0％。变异系数（CV）为B1 4．8％－7．2％,B2 6．3％－8．9％。检测低限为B1 0．005mg/kg,B2 0.01mg/kg。     

电位滴定法测定干红葡萄酒中SO2含量

在生产中利用电位滴定法测定干红葡萄酒中SO2的含量,避免了直接碘量法终点识别的困难.总结出一种快速、准确而有效的分析方法.     

电位滴定法测定漂白废水中总有机氯化物的研究

利用电位滴定法测定漂白废水中的氯离子用银量法简单，终点判断容易，准确度高。以Ｓｃｈｏｎｉｇｅｒ燃烧法和电位滴定法测定漂白废水中的总有机氯化物，操作简单、准确度较高、测定时间短且费用低，适于国内纸厂日常检测。     

Determination of As(III) and As(V) in oilseeds by chronopotentiometric stripping analysis: development of a method

Chronopotentiometric stripping analysis (CSA) was used for selective determination of As(III) and As(V) in different oilseeds. After the optimization of experimental parameters an appropriate procedure for sample pretreatment was developed. A detection limit of 2 microg/dm3 for As(III) was obtained with an electrolysis time of 600 s. This method was used for arsenic determination in sunflower, pumpkin, and flax seed, as well as for soy flakes and almond.