葡萄酒中二氧化硫含量的快速测定

采用凯氏定氮仪对葡萄酒样品进行蒸馏,然后用自动电位滴定仪测定葡萄酒中二氧化硫的含量。考察了凯氏定氮仪与玻璃蒸馏仪、自动电位滴定仪与玻璃滴定管、搅拌速度及滴定速度对测定结果的影响。测定结果显示,凯氏定氮仪-自动电位滴定仪测定结果与GB/T5009.34-2003规定的采用玻璃仪器方法测定结果无显著性差异。该方法的加标回收率为88.8%~103.6%。     

自动电位滴定法测定高纯氯化铵的纯度

建立自动电位滴定法测定高纯试剂氯化铵纯度的方法。以硝酸银标准滴定溶液作滴定剂,采用自动电位滴定仪测定高纯氯化铵的含量。测定结果的相对标准偏差为0.03%(n=6)。采用该法与化学滴定法对高纯氯化铵样品进行测定,两种方法的测定结果无显著性差异。该方法操作简便、快捷,自动化程度高,滴定终点判断敏锐,测定结果准确可靠。     

连续流动法同时测定污水中氨氮和总磷

采用连续流动分析法测定污水中氨氮、总磷的含量。比较了污水样品不同的稀释倍数对测定结果的影响。实验结果表明:氨氮和总磷的质量浓度在0.1~8 mg/L范围内线性良好,线性相关系数均为0.99997;测量结果的相对标准偏差分别为2.01%,0.84%(n=7);方法检出限分别为0.012,0.009 mg/L;质控样测量值均在标示值范围内;样品加标回收率为93.4%~101.1%。污水的洁净程度对测定结果影响较大。洁净度高的污水,直接测定与稀释后测定,测定值无显著性差异;而洁净度低的污水,直接测定与稀释后测定结果差异比较大。该法采用全谱直读CCD检测方式,灵敏度高,稳定性好,无光谱干扰,且支持氨氮和总磷同时测定,方便快捷,适合污水中氨氮和总磷的测定。     

全自动电位滴定法测定锂电池原料碳酸锂中碳酸锂的含量

采用全自动电位滴定法测定锂电池原料碳酸锂中碳酸锂的含量,用盐酸标准溶液进行滴定,考虑自动电位滴定仪的灵敏性和准确度,通过多次对比实验,确定了仪器的最佳工作参数、滴定剂浓度和样品称样量等滴定条件;对2个不同品味试样分别进行了11次平行测定,相对标准偏差（RSD）均小于 1%。在碳酸锂试样中加入基准物质无水碳酸钠进行碳酸根的加标回收实验,碳酸根的加标回收率在99.4%～100.2%之间。与传统的酸碱滴定法相比,全自动电位滴定法方便、快捷,同时该方法测定结果准确、可靠、精密度高,适合大批量快速分析样品。     

全自动电位滴定法测定锂电池原料碳酸锂中主成分的含量

采用全自动电位滴定法测定锂电池原料碳酸锂中主成分的含量,用盐酸标准溶液进行滴定,考虑自动电位滴定仪的灵敏性和准确度,通过多次对比实验,确定了仪器的最佳工作参数、滴定剂浓度和样品称样量等滴定条件;对两个不同品位试样分别进行了11次平行测定,相对标准偏差(RSD)均小于1%。在碳酸锂试样中加入基准物质无水碳酸钠进行碳酸根的加标回收实验,碳酸根的加标回收率在99.4%~100%。与传统的酸碱滴定法相比,全自动电位滴定法方便、快捷,同时方法测定结果准确、可靠、精密度高,适合大批量样品快速分析。     

电位滴定法测定抛光液中的三酸含量

探讨了利用自动电位滴定仪对抛光液中磷酸、硫酸及硝酸的分析方法,以及对溶剂的标定方法。电位滴定法测定三酸,先用硫酸亚铁铵滴定硝酸,再用氢氧化钠滴定磷酸和硫酸,从而计算三酸含量。结果表明,与传统滴定法相比,电位滴定法标定硫酸亚铁铵的相对标准偏差(RSD)从1.1%降至0.13%,标定氢氧化钠的RSD从0.72%降至0.06%。电位滴定法测定自配样品及工厂抛光产品中的硝酸,回收率分别在96%及93%以上。电位滴定法测定自配样品及工厂抛光产品中磷酸和硫酸的回收率偏差在3%以内。手动滴定法测定磷酸和硫酸的回收率偏差在5%~10%,回收效果不如电位滴定法。电位滴定法测定工厂抛光液的三酸加标回收率偏差均小于3%。自动电位滴定法比手工滴定的准确性和精密度明显提高,弥补了手工滴定法只能分析磷酸和硫酸,而无法测定硝酸的缺陷。     

电位滴定法测定抛光液中的三酸含量

探讨了利用自动电位滴定仪对抛光液中磷酸、硫酸及硝酸的分析方法,以及对溶剂的标定方法。电位滴定法测定三酸,先用硫酸亚铁铵滴定硝酸,再用氢氧化钠滴定磷酸和硫酸,从而计算三酸含量。结果表明,与传统滴定法相比,电位滴定法标定硫酸亚铁铵的相对标准偏差(RSD)从1.1%降至0.13%,标定氢氧化钠的RSD从0.72%降至0.06%。电位滴定法测定自配样品及工厂抛光产品中的硝酸,回收率分别在96%及93%以上。电位滴定法测定自配样品及工厂抛光产品中磷酸和硫酸的回收率偏差在3%以内。手动滴定法测定磷酸和硫酸的回收率偏差在5%～10%,回收效果不如电位滴定法。电位滴定法测定工厂抛光液的三酸加标回收率偏差均小于3%。自动电位滴定法比手工滴定的准确性和精密度明显提高,弥补了手工滴定法只能分析磷酸和硫酸,而无法测定硝酸的缺陷。     

电位滴定法测定火试金得到的金银合粒中的银

本文研究了用自动电位滴定仪测定外购铜物料样品中经火试金熔炼、富集、灰吹后得到的金银合粒中银的方法。金银合粒用硝酸溶解后在自动电位滴定仪上用硫氰酸钾标准溶液滴定银量,选择了仪器的测定条件,考察了溶液酸度、共存元素对测定的干扰。方法相对标准偏差为1.34％～3.62％,测定结果与硫氰酸钾手工滴定法和减杂法相一致。方法的准确度和精密度均能满足分析需要,具有较强的实用性和推广价值。     

ICP-AES法测定高含量有机物中镧系元素的消解方法比较

采用HNO3消解法、HNO3-双氧水消解法、HNO3-HCl O4消解法处理高含量有机物体系中镧系金属样品,用HK-8100型ICP-AES光谱仪测定消解后的镧系金属离子浓度,比较3种酸消解方法的相对误差率,发现HNO3-双氧水消解法中,10 m L样品中HNO3和双氧水用量为1 m L和2 m L时,误差率最小,消解效果最好。     

自动电位滴定法测定对氨基苯酚氨基值

建立了一种利用自动电位滴定仪测定对氨基苯酚(PAP)氨基值的方法,根据重氮化反应的原理,分别从反应温度、滴定方式以及无机酸的种类和浓度条件进行了优化,样品在氢溴酸/盐酸体系,35℃滴定温度自动滴定氨基值。结果表明,对氨基苯酚样品的氨基值与手动滴定法相差较小,加标回收率在98.8%～101%,与国家标准方法"GB/T 21892—2015"对比,具有操作简便,自动化程度高,滴定终点判断敏锐,测定结果准确可靠的优点,可用于PAP的氨基值测定。     

复混肥料中氯离子含量测量不确定度的评定

对硫氰酸铵滴定法测定复混肥料中氯离子含量的测量不确定度进行了评定。分析了测量重复性、滴定管、标准溶液浓度等因素对氯离子含量测量不确定度的影响。计算得复混肥料中氯离子含量测定结果的扩展不确定度为0．049％。     

离子色谱法测定“地沟油”中钠离子和氯离子的含量及其比例关系

采用离子色谱法测定“地沟油”样品中钠离子和氯离子的含量,通过计算两者的比例关系确定样品中是否含有“地沟油”。使用去离子水提取“地沟油”样品中钠离子和氯离子。氯离子以20 nmol/L KOH溶液为淋洗液,AS19分离柱(250 mm×4 mm)分离,抑制器电流112 mA;钠离子以20 nmol/L甲基磺酸(MSA)为淋洗液,CS12分离柱(250 mm×4 mm)分离,抑制器电流59 mA;两者分离采用的其他相同色谱条件为: 柱温、检测器温度30 ℃,电导检测器检测,进样量25 μL,流量1 mL/min,峰面积定量。氯离子的检出限为0.005 mg/L,在0～5 mg/L范围内有良好的线性关系（r2=0.999988）;钠离子的检出限为0.001 mg/L,在0～5 mg/L范围内有良好的线性关系（r2=0.999926）。氯离子平均加标回收率为94.2%,相对标准偏差(RSD)为2.4%;钠离子平均加标回收率为92.5%, RSD为2.7%。经测定、计算,正常食用油中钠离子和氯离子的物质的量比约为1,而“地沟油”中钠离子与氯离子的物质的量比高于4。“地沟油”中钠离子和氯离子的含量及其比例关系可作为判断“地沟油”的重要依据。     

A rapid and mercury pollution-free redoximetry determination of total iron in copper ore

A rapid and mercury pollution-free method for the determination of total iron in the presence of copper is described. The sample was decomposed either by an acid attack of hydrochloric acid-nitric acid (1 + 2) or by fusion with sodium peroxide. The ferric ion in the sample solution was amenable to direct reduction to ferrous ion with potassium borohydride in sulphuric acid medium under the catalysis of cupric ion, followed by titration with potassium dichromate using sodium diphenylaminesulfonate as an indicator. After reduction, the iron (II) in the solution was stable for 300 min. The proposed method is free of interference from copper and has been successfully used for the large-scale routine determination of total iron in copper ores showing the same or better degree of precision and accuracy as those obtained by the classic standard stannous chloride-mercuric chloride method with the separation of iron from copper.     

Energy dispersive X-ray fluorescence analysis of chloride in reforming catalysts

A relatively less expensive Phillips PV 9500/SY 585 automatic energy dispersive X-ray fluorescence (EDXFR) spectrometer with rhodium target, was modified using a commercial kitchen aluminium wrapping foil filter, for the determination of chloride in bifunctional reforming catalysts. Quantitation of chloride was carried out by the Claisse-Quintin method with a catalyst sample of known chloride content as an external standard. The results of EDXRF chloride analysis of different catalyst samples, containing varying amounts of percent carbon and chloride, compared well (p>0.75) with those obtained by silver chloride precipitation method. The small values of percent relative standard deviations at 0.4 to 4.5% showed a good reproducibility of the method. With the total analysis time of a few minutes combined with no sample preparation, the present method seems to be superior as compared to presently employed methods of chloride analysis in reforming catalysts.     

全自动电位滴定法测定混凝土中酸溶氯离子含量

采用全自动电位滴定仪测定混凝土中氯离子含量,研究了实验相关影响因素.实验结果表明,pH值和AgNO3溶液浓度对试验结果无显著影响,在水溶液中加入乙醇有利于提高终点电位突跃,该方法加标回收率为96.9%～98.7%,测量结果的相对标准偏差为2.74%(n=6).     

全自动凯氏定氮仪测定化肥中的含氮量

建立全自动凯氏定氮仪检测化肥中氮含量的分析方法。称取总氮量在0.03~0.3 g范围的样品,经消解仪消解及全自动凯氏定氮仪碱化蒸馏,以硼酸为接收液,用0.15~0.20 mol/L的盐酸标准溶液进行自动滴定。该方法加标回收率为99.0%~101.5%,测定结果的相对标准偏差小于1.0%(n=6)。与国标GB/T 8527–2010法测定结果无显著性差异,全自动凯式定氮仪法的准确度、精密度均优于国标方法,而且所用试剂少、分析时间短,满足实验室快速检测大批量化肥中含氮量的需要。     

Enzymatic determination of choline in milk using a FIA system with potentiometric detection

The development of a FIA system for the determination of total choline content in several types of milk is described. The samples were submitted to hydrochloric acid digestion before injection into the system and passed through an enzymatic reactor containing choline oxidase immobilised on glass beads. This enzymatic reaction releases hydrogen peroxide which then reacts with a solution of iodide. The decrease in the concentration of iodide ion is quantified using an iodide ion selective tubular electrode based on a homogeneous crystalline membrane. Validation of the results obtained with this system was performed by comparison with results from a method described in the literature and applied to the determination of total choline in milks. The relative deviation was always < 5%. The repeatability of the method developed was assessed by calculation of the relative standard deviation (RSD) for 12 consecutive injections of one sample. The RSD obtained was < 0.6%.     

硫氰酸汞间接分光光度法测定三乙基铝中氯的含量

建立了测定三乙基铝中氯含量的硫氰酸汞间接分光光度法。在酸性溶液中,硫氰酸汞与氯离子反应后游离出硫氰酸根离子,硫氰酸根离子与铁离子反应生成红色硫氰酸铁络合物,于460 nm波长处测定该络合物的吸光度,从而间接获得氯的含量。对测量过程的波长、酸度、显色剂的用量、显色剂的稳定性等因素进行了探讨。氯的质量在0~50μg范围内与吸光度呈良好的线性关系,线性相关系数r=1.000 0,测定结果的相对标准偏差为0.07%~0.20%(n=6),加标回收率为94.8%~105.0%。该法适用于三乙基铝工业品中氯含量的测定。     

Pollution-free method for the determination of iron in iron ore

A method for the determination of total iron in iron ores and concentrates is described which avoids the use of mercuric chloride. The sample is decomposed either by an acid attack or by fusion with sodium peroxide. The hot sample solution in about 6M hydrochloric acid is treated with hot 10% stannous chloride solution till pale yellow, followed by addition of a slight excess of 2% titanous chloride solution; the excess is then oxidized with perchloric acid (1 + 1). The solution is rapidly cooled in ice-water, and the iron (II) is titrated with potassium dichromate (sodium diphenylsulphonate as indicator). The results show the same degree of precision, accuracy, and degree of interference as those obtained by the standard stannous chloride-mercuric chloride method.     

Cobalt chloride in a saturated calcium chloride solution as a titrant for the determination of moisture traces in oil

A new titrimetric procedure has been developed for the determination of moisture traces in oil. The procedure uses cobalt chloride in a saturated calcium chloride solution as a titrant. The relative standard deviation of the procedure is no more than 0.17%, the relative error is 3.8%, and the analytical range of the moisture content is 0.010-0.100%.