刚果红水杨酸法测定水中的微量镁

建立一种简便快速的水中微量镁的测定新方法。利用镁离子与刚果红、水杨酸反应,在0.08mol/L的NaOH溶液的条件下显色,进行分光光度分析。在实验最适条件下,镁离子含量在0.01μg-2μg/ml之间时,镁离子含量与吸光度线性关系良好,方法检出限为0.08μg/ml相对标准偏差4.3%,样品加标回收率在96%~106%。本方法操作简便,灵敏度高。用于水中微量镁的测定,结果满意。     

乳与乳制品中L（-）-羟脯氨酸含量的测定方法

目的：改进乳与乳制品中动物水解蛋白鉴定-L（-）-羟脯氨酸含量测定法（卫生部指定方法）。方法：在其前处理过程中用硫酸溶液代替氯化亚锡盐酸溶液水解样品,用烘箱代替了水浴水解样品,改动了试样前处理和测定操作。方法的线性范围0μg/L～2．0μ／mL,相关系数7-0．99993,加标回收率为89．5％-101．0％。结论：该方法显色灵敏,稳定性好,准确,干扰少,适用于乳及乳制品中-L（-）-羟脯氨酸含量测定。     

硫酸铁铵滴定法测定低密度铌合金中钛元素

通过对干扰元素和试剂加入量进行实验分析,建立了用硫酸铁铵滴定法测定铌钛铝基低密度铌合金中钛元素含量的方法,根据所用硫酸铁铵滴定溶液的体积计算样品中的钛含量。该方法钛元素含量加标回收率在98.48%~102.19%之间,RSD为0.37%。     

苯芴酮光度法快速测定镀银溶液中的微量锑

利用苯芴酮与锑(Ⅲ)的显色反应,对镀银溶液中的锑进行光度测定.试验结果表明,在乳化剂OP存在下的0.09～0.18 mol/L硫酸介质中,显色体系的最大吸收波长位于560 nm.表明摩尔吸光系数为5.85×104L/(mol·cm),锑浓度介于0.14～1.40μg/mL,遵守比尔定律.加标回收率97.3%～104.7%,本方法简便快速,且具有良好的选择性.     

紫甘蓝花青素分光光度法同时测定微量铝和铁

在pH 4.7的醋酸-醋酸钠缓冲体系中,自紫甘蓝中提取并经纯化的花青素与Al3+和Fe3+发生络合反应,花青素和两种络合物最大吸收波长分别为550,585,630nm。利用吸光度的加和性,建立起铝和铁混合溶液在585nm和630 nm波长处的工作曲线方程组,铝和铁含量在0.1～1.0 mg/25 mL范围内与吸光度呈良好的线性关系,相关系数大于0.995,络合物摩尔吸光系数大于103L.mol-.1cm-1。方法定量检出限铝为47.71μg/25mL、铁为26.12μg/25mL。方法应用于国家土壤标准样品(GBW07408)的测定获得准确结果,土壤样品加标回收率铝在96.1%¹08.0%之间、铁在95.4%108.0%之间、铁在95.4%¹08.1%之间,土壤样品测定精密度符合光度法要求。该方法干扰离子较少、显色时间短、络合物稳定,可用于低常量和微量铝和铁的同时测定。     

分光光度法快速测定液态食品中糖精含量的研究

利用糖精在磷酸缓冲液中与天青Ⅰ反应生成蓝色化合物,二氯甲烷能萃取糖精与天青Ⅰ形成的蓝色复合物而不萃取天青Ⅰ,通过分光光度法可以快速简便地测定液态食品中糖精的含量.糖精与天青Ⅰ形成的蓝色复合物的最大吸收波长为640nm,当样品液取样量为10.0mL、0.2mol/L pH5.0磷酸氢二钠-柠檬酸缓冲液用量为10mL、0.05%天青Ⅰ溶液用量为0.5mL、显色时间为5min、二氯甲烷萃取剂用量为10.0mL时,糖精质量浓度在0～120mg/L范围内与吸光度值呈线性,最低检出限为1.5mg/L.该法应用于四种液态食品中糖精含量的测定,回收率在90%～103%之间,相对标准偏差小于5.0%.     

用双环己酮乙二酰二腙分光光度法测定浸锌液中的Cu2+

基于铜与双环己酮乙二酰二腙(BCO)的显色反应,以柠檬酸铵为掩蔽剂,氯化铵-氨水为缓冲溶液,调节溶液pH值为8.6～10.0,使铜与BCO的蓝色生成物稳定保持在水相中,直接进行光度分析,据此建立了测定浸锌液中铜的分光光度分析法.测试结果显示:显色溶液在600nm处有最大吸收峰,Cu2+测量的范围是0.02～4.00mg...     

连续流动法快速测定电子烟烟油中甲醛和乙醛总含量

称取电子烟烟油1.0000g,用20％的乙醇水溶液定容至25mL,摇匀后采用连续流动-分光光度法分析,烟油中醛基与酚试剂在线反应生嗪,嗪在酸性溶液中被高铁离子氧化形成630nm处有吸收的蓝色绿色复合物,通过监测630nm处吸光度的变化,可推算得到烟油中甲醛和乙醛的总含量.结果表明:①该方法仪器流路最佳配制为样品溶液和硫酸铁铵试剂用橙/白泵管,酚试剂用灰/灰泵管,反应混合圈为5匝;②在优化的实验条件下,该方法检出限为0.42mg/kg,定量限为1.40mg/kg,加标回收率为(96.50～106.44)％,相对标准偏差均小于2％;③该方法成本低廉、前处理简单、测定快速、定量准确、检出限低,非常适合大批量电子烟烟油的检测.     

火焰原子吸收分光光度法测定环境水样中钾和钠

采用火焰原子吸收分光光度法测定环境水样中钾和钠的含量,通过对不同波长条件下钾钠吸光度的比较,选择出最佳灵敏线应用于本机分析试验,过程简单,效果十分理想。方法灵敏度高、线性关系良好、结果准确稳定,检出限钾为0.005mg/L、钠为0.008mg/L。应用此方法测定2种水样中的钾和钠,相对标准偏差1.2%～1.9%,回收率95.2%～103.2%。     

催化光度法测定处理电镀废水中的微量镉

在HAc-NaAc缓冲溶液中,痕量镉(Ⅱ)对H2O2氧化还原型若丹明B的显色反应有强的催化作用,催化程度与镉(Ⅱ)量呈线性关系.由此建立了测定痕量镉(Ⅱ)的分光光度法.结果表明,有色溶液的最大吸收波长为560 nm,方法检出限为0.32μg/L,催化程度与镉(Ⅱ)量在0～0.040 mg/L范围内符合比耳定律,加标回收率为96.5%～100.1%之间,结合KI-MIBK萃取分离,测定了处理电镀废水中的微量镉(Ⅱ).     

Chloroform Aided Extraction Spectrophotometric Determination of Rhenium Using Thiocyanate Complexing Agent

A new technique is developed for quantitative determination of rhenium in aqueous media containing molybdenum, iron and copper ions. The method seems easier and more accurate than the traditional ones. It consists of the formation of rhenium thiocyanate complex, which is extracted with chloroform at the presence of hydrochloric acid. This complex is a highly visible light absorbent that can easily be detected with the aid of a spectrophotometer. The maximum absorbance (λmax) observed for this complex was in the visible range of 430-435 nm. The experimental results showed that in a concentration range from 0.5-8 mg/L, the absorbance behavior of the rhenium thiocyanate complex is followed to the Beer-Lambert law.     

原料奶中尿的掺假定性检测方法

研究了原料乳中尿的检测方法,尿中含有肌酐,复合苦味酸肌酐就是在pH值为12的条件下,肌酐与苦味酸反应而成的。通过颜色的变化判断鲜乳中是否有尿的存在。结果表明,该方法用于检测原料乳中尿含量在4%以上含量具有明显的颜色变化,同时方法操作简单,结果判定较直观。适用于乳品企业进行尿定性的检测。     

高效液相色谱法测定罗汉果甜甙中甜蜜素

采用高效液相色谱法测定了罗汉果甜甙中的甜蜜素。将样品溶于水后,用Carrez试剂沉淀其中的杂质,离心,用次氯酸钠将样品溶液中的甜蜜素转化为N,N-二氯环己胺经正己烷萃取后测定。采用EclipseXDB-C18不锈钢柱分离,以乙腈-水(85+15)作流动相,二极管阵列检测器检测波长为314nm。结果显示,甜蜜素在样品溶液浓度为0.1mg/L~2mg/L范围内呈良好的线性关系,回收率为89.9%~94.7%,检出限为5mg/kg,测定结果的相对标准偏差小于5%。方法操作简便,结果准确可靠。     

微波辅助萃取/分光光度法快速测定抗菌纺织品中的三氯生

为了测定抗菌纺织品中三氯生的含量,本文以二氯甲烷为萃取溶剂,采用微波萃取技术萃取抗菌纺织品中的抗菌剂三氯生。萃取液蒸发至干后,用甲醇定容,然后以甲醇为参比溶液,在282nm波长下测定其吸光度,从而建立了一种测定抗菌纺织品中的抗菌剂三氯生的分光光度方法,并对萃取条件、方法的线性关系、精密度、回收率、检出限等进行了研究。三氯生在0.2-80mg/L范围内呈现良好的线性关系,线性相关系数为0.9998,回收率为91.98%-104.94%,相对标准偏差均小于6%,检出限为0.1mg/kg(S/N=3)。采用该方法对市售抗菌纺织品进行检测,发现部分抗菌纺织品中使用高含量的三氯生。     

The Inhibitive Effect of para-Amino Benzoic Acid and Its Polymer on Corrosion of Iron in 1 mol/L HC1 Solution

Poly p-aminobenzoic acid has been synthesized by chemical oxidation method. The inhibitive effect of poly p-aminobenzoic acid on iron in 1 mol/L HCl solution was investigated by polarization and electrochemical impedance spectroscopy and compared with that of monomer p-aminobenzoic acid. The effectiveness of poly p-aminobenzoic acid is very high in comparison with that of monomer. The results show that both cathodic and anodic processes were suppressed by p-aminobenzoic acid and poly p-aminobenzoic acid of iron dissolution in 1 mol/L HCI by their adsorption on the iron surface. The inhibition efficiency of both p-aminobenzoic acid and poly p-aminobenzoic acid were found to increase with the inhibitor concentrations. Ultraviolet (UV) reflectance studies of the iron surface after exposure to inhibitor acid show that poly p-aminobenzoic acid is strongly adsorbed on iron surface.     

Autoanalyzer for milk quality control based on the lactose,fat, and total protein contents

A novel autoanalyzer was developed to assess the quality of milk samples according to the percentage of lactose, fat, and total protein they contain. The module comprises two pumps (one of high pressure), an injection valve, a filter, and an evaporative light-scattering detector. A volume of 15 microL of dilute milk was injected in an ethanol-water (50% v/v) stream for precipitation/retention of protein/fat, being the lactose content determined in the filtrate. The fat fraction was calculated using an ethanol stream, and total protein was finally dissolved by means of a 1.7 mol/L acetic acid solution. The simplicity of the proposed automatic module lies in the universal response of the detector, which permits the determination of the three macrocomponents in milk. In addition, the flow injection method allows their sequential analysis in the same injected sample by using selective reagents for each compound. The proposed method was validated with an SRM milk sample as well as by comparison of the results obtained with those provided by the IR method. In addition, the proposed analyzer is cheaper than its counterpart that is based on infrared technique.     

氧化铁皮制备纳米高纯氧化铁

本文介绍了以氧化铁皮为原料,经过盐酸酸浸、还原铁粉除杂获得净化的FeCl2溶液,纯净FeCl2溶液的合理工艺条件为：盐酸浓度为6mol／1,酸浸温度80℃,酸浸时间30min,盐酸过量系数为1．74。此工艺条件下,铁的浸出率达94．5％。制备FeCO3条件：FeCl2的初始浓度为0．8mol／l,CO3^2-：Fe^2＋摩尔比为2;反应时间为60min;反应温度40℃;搅拌速度为250r／min;沉淀物在60℃下干燥1h,700℃下煅烧2h,获得椭球形分散性较好的,平均粒径为47nm的氧化铁。     

氢化物发生原子荧光谱法测定婴幼儿奶粉中硒

本文采用硝酸-高氯酸处理样品,以氢化物发生原子荧光谱法测定婴幼儿奶粉中硒的含量,方法检出限为0.2μg/L,在0~150μg/L范围内线性相关系数0.9995,样品加标回收率92.5%~105.8%,相对标准偏差为5.6%。     

The Inhibitive Effect of para-Amino Benzoic Acid and Its Polymer on Corrosion of Iron in 1 mol/L HCl Solution

Poly p-aminobenzoic acid has been synthesized by chemical oxidation method. The inhibitive effect of poly p-aminobenzoic acid on iron in 1 mol/L HCI solution was investigated by polarization and electrochemical impedance spectroscopy and compared with that of monomer p-aminobenzoic acid. The effectiveness of poly p-aminobenzoic acid is very high in comparison with that of monomer. The results show that both cathodic and anodic processes were suppressed by p-aminobenzoic acid and poly p-aminobenzoic acid of iron dissolution in 1 mol/L HCI by their adsorption on the iron surface. The inhibition efficiency of both p-aminobenzoic acid and poly p-aminobenzoic acid were found to increase with the inhibitor concentrations. Ultraviolet （UV） reflectance studies of the iron surface after exposure to inhibitor acid show that poly p-aminobenzoic acid is strongly adsorbed on iron surface.