Application of potassium ferricyanide in the spectrophotometric determination of captopril

A novel method for the determination of captopril by spectrophotometer is described in this paper. The experiment is based on the fact that Fe（Ⅲ） is reduced to Fe（Ⅱ） by captopril, then the in sire formed Fe（Ⅱ） reacts with potassium ferricyanide to give the soluble prussian blue at pH 4.00, and its maximal adsorption wavelength （λmax） is 735 nm. Good linear relationship is obtained between the absorbance and the concentration of captopril in the wide range of 0.05-20 μg/mL. The linear regression equation is A = -0.04314 ＋ 0.11423C （μg/mL） with a correlation coefficient R = 0.9998. The detection limit （3σ/k） is 0.04 μg/mL, the molar absorption coefficient is 2.5×10^4 L/mol cm. By mensurating the absorbance of soluble prussian blue, the indirect determination of captopril can be obtained. This method has been successfully applied to determination of captopril in pharmaceutical samples. Analytical results obtained are satisfactory.

Developed New Procedure for Low Concentrations of Hydrazine Determination by Spectrophotometry: Hydrazine-Potassium Permanganate System

An indirect, sensitive and accurate method for the determination of trace amounts of hydrazine is described. In this proposed the spectrophotometric method is based on its reduction properties of hydrazine with a known concentration of potassium permanganate to reduce the colour. The absorbance of unreduced permanganate is measured the colour difference at different wavelengths 546 and 526 nm which show an absorption spectrum with hydrazine. Hydrazine can be determined in the range of 100 - 700 μg/ml with correlation coefficient of 0.999 and relative standard deviation 1%. The method is successfully applied for the determination of hydrazine in water streams in nuclear reactors/purex process/boiler water and polluted water samples.

Mechanistic Study and Kinetic Determination of Cu(Ⅱ) by the Catalytic Kinetic Spectrophotometric Method

A highly sensitive and selective catalytic kinetic spectrophotometric method for the determination of Cu(Ⅱ) is proposed. It is based on the catalytic effect of Cu(Ⅱ) on the oxidation of glutathione(GSH) by potassium hexacyanoferrate(Ⅲ) in acidic medium at 25.0℃. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of oxidant at 420 nm using the fix-time method. Under the optimum conditions, the proposed method allows the determination of Cu(Ⅱ) in a range of 0-35.0 ng m L^(-1) with good precision and accuracy and the limit of detection is down to 0.04 ng m L^(-1). The relative standard deviation(RSD) is 1.02%. The reaction orders with respect to each reagent are found to be 1, 1/2, and 1/2 for potassium hexacyanoferrate(Ⅲ), glutathione and Cu(Ⅱ) respectively. On the basis of these values, the rate equation is obtained and the possible mechanism is established. Moreover, few anions and cations can interfere with the determination of Cu(Ⅱ). The new proposed method can be successfully used to the determination of Cu(Ⅱ) in fresh water samples and seawater samples. It is found that the proposed method has fairly good selectivity, high sensitivity, good repeatability, simplicity and rapidity.

Application and Perception of Potassium Iodide Following Silver Diamine Fluoride Treatment

Silver Diamine Fluoride (SDF) is colorless and alkaline with a pH of 10. It has been used in Japan and other international countries for decades. The Food and Drug Administration gave approval for it as a means of treating hypersensitivity for individuals with chronic teeth pain. SDF is also used as a method to treat and arrest dental caries. SDF application is limited due to its negative esthetic effects, which is a black stain where the cavity was present on the tooth. Topical application of potassium iodide applied immediately after SDF has been shown in studies to reduce the color change caused by SDF. This study used topical application of silver diamine fluoride (SDF) and potassium iodide (KI) treatments on bovine teeth to determine if SDF and KI were efficacious in the treatment for carious lesions. The color change was detected by use of spectrophotometric analysis to determine L, a and b readings that demarcate light and color values following staining. The conclusion was made that the application of SDF followed directly by KI treatment produced L, a and b spectrophotometric values that indicated a significant reduction in teeth staining than the application of SDF alone. Therefore, this study supports the idea that SDF and KI can be used to treat carious lesions on bovine teeth while retaining surface enamel coloration.

萃取分光光度法测定氯化钾体系中的十八胺

十八胺是冷结晶-正浮选法生产氯化钾的常用捕收剂,用量显著影响浮选分离效率。由于其会吸附在氯化钾表面,不可避免地在氯化钾中残留,不利于高纯钾盐产品的开发。针对氯化钾生产过程及产品中十八胺含量测定的需求,依据十八胺和溴酚蓝通过范德华力和氢键络合的作用原理,开发了以乙酸丁酯为萃取剂、溴酚蓝钠盐为显色剂的萃取分光光度法测定氯化钾中十八胺的浓度。考察了溶液pH、十二烷基吗啉、共存盐、平衡时间、显色剂用量对十八胺浓度测量的影响。结果表明:当溶液pH从3~9逐渐增大时,十八胺与溴酚蓝的络合作用减弱且络合分子极性增大,导致吸光度降低;在pH<5时,十二烷基吗啉和溴酚蓝能形成有色络合物,当pH为6~9时萃取液吸光度值趋近于零;共存氯化钾、氯化钠、硫酸钾、氯化镁等溶液的离子强度增大,氢键作用减弱但络合分子的盐析效应增强,溶液中微量的Li^(+)、NH_(4)^(+)和B对萃取液吸光度影响不大;显色剂用量过大时,吸光度值太大且不符合朗伯-比尔定律,平衡时间影响较小。选择测定条件为:溶液的pH为6、离子强度为1 mol·L^(-1),2 mmol·L^(-1)显色剂的用量为0.50 mL,采用缓冲溶液定容至25 mL,反应5 min后加入5.00 mL乙酸丁酯萃取,待分层平衡2 min后于458 nm处测定萃取液吸光度,工作曲线为A=0.04949c+0.06624(R^(2)=0.9923,ε=1.33×10^(4) L·mol^(-1)·cm^(-1),0~10 mg·L^(-1))。该方法的相对标准偏差为0.33%~2.63%,平均相对误差为-0.90%,十八胺和十二烷基吗啉混合体系的平均相对误差为-0.25%。采用该方法测得正浮选精钾母液中十八胺含量为8.66 mg·L^(-1),加标回收率为95.5%~106%,可用于测定盐湖钾肥生产过程中十八胺的浓度。

在线紫外光直接活化过硫酸钾消解-磷钼蓝分光光度法测定环境水样中总磷的含量

设计并建立了一种在线紫外光直接活化过硫酸钾消解-磷钼蓝分光光度法测定环境水样中总磷含量的系统和方法,并优化验证了系统参数和方法,进行了实际水样的总磷含量测定。水样与过硫酸钾溶液注射混合进入石英螺旋管,紫外光照射活化过硫酸钾消解水样,与抗坏血酸和钼酸铵还原显色后在700 nm处测定吸光度。在石英螺旋管温度为20℃,水样、过硫酸钾、抗坏血酸、钼酸铵流量分别为1.00,0.15,0.06,0.08 mL·min^(-1)的优化条件下,消解率达到97.0%以上,总磷的质量浓度在0.1~5.0 mg·L^(-1)内与吸光度呈线性关系,检出限(3s/k)为0.007 mg·L^(-1)。本方法测定水样的结果与国家标准GB 11893—89进行对比,相对误差为-4.0%~-0.50%。按照标准加入法对湖水样品进行回收试验,回收率为93.0%~100%,测定值的相对标准偏差(n=6)小于3.0%。

碱性过硫酸钾-紫外分光光度法测定水质总氮方法的改进

水质总氮是指示水体富营养化的重要标志物,因此,开发测定水体中总氮的准确方法,对研究水体中的污染物来源、污染程度及总氮的地球化学循环过程具有重要意义。测定水质样品中的总氮,通常采用碱性过硫酸钾-紫外分光光度法,但该法对空白吸光度有严苛的要求,空白吸光度一旦超过0.030,就有可能导致测定结果严重偏低,其中,过硫酸钾的纯度和存放时间可能对测定结果影响最大;同时,采用比色管捆绑方式高温高压消解水质样品,导热较慢,消解时间偏长,捆绑时一旦比色管上的标签或记号脱落,容易导致样品混乱;样品保存条件不当也很容易造成测定结果偏低。为提高水质样品中总氮测定结果的准确性和效率,本文通过对国内外不同厂家生产的过硫酸钾进行总氮空白吸光度和存放时间对比实验,然后对两种消解方法进行消解时间对比实验,最后,对比了两种不同水质样品保存方法对测定结果的影响。对比实验结果表明:国产优级纯碱性过硫酸钾存放时间在30天内,其水质总氮空白吸光度均小于0.030;在124℃条件下,使用插置法消解样品,只用20min就能使样品消解完全;对酸化后的水质样品,其保质期从1天延长至7天。研究认为,选用国产优级纯过硫酸钾和改良过的插置法消解水质样品,与捆绑法相比,其水质总氮检出限更低,消解效率更高,且不容易出现互相污染和样品错位等情况,提高了水质总氮测定的准确度。

天然水体中钾、钠、钙、镁测定方法的比对

电感耦合等离子体发射光谱法和火焰原子吸收分光光度法测定天然水体中钾、钠、钙、镁,比较相关系数、检出限、精密度、准确度和实际样品的测定,结果表明:两种方法均可用于天然水体中钾、钠、钙、镁的测定,且电感耦合等离子体发射光谱法更优。

原子吸收分光光度法-火焰法测定复方醋酸钠林格注射液中钠、钾、镁、钙离子的含量

目的:建立复方醋酸钠林格注射液中钠、钾、镁、钙离子含量的原子吸收分光光度法-火焰法测定方法。方法:采用A3AFG-12型A3原子吸收分光光度计和XS205DU型、XP6型电子天平,以氯化铯作为测定钠离子和钾离子时的电离抑制剂,氯化镧为测定镁离子和钙离子时电离抑制剂,分别在589.3、766.5、285.2、422.7 nm处测定钠、钾、镁、钙离子含量,并进行方法学验证。结果:4种离子分别在0.15~1.20、0.2~1.6、0.05~0.4、1.014~5.069μg·mL^(-1)的浓度范围内线性关系良好,相关系数分别为r=0.9996、r=0.9993、r=0.9996、r=0.9990;4种离子平均回收率分别为98.5%,98.1%,93.2%,95.0%;测定注射液样品5批,钠、钾、镁、钙离子含量分别在3.186~3.221、0.155~0.160、0.023~0.026、0.056~0.059 mg·mL^(-1)范围内。结论:经方法学验证,所建立的方法重现性强、准确度高,适用于复方醋酸钠林格注射液中钠、钾、镁、钙离子的含量测定。

重铬酸钾分光光度法测定平湖糟蛋中乙醇含量

通过对平湖糟蛋样品前处理方式以及乙醇测定反应体系的优化,建立了重铬酸钾分光光度法测定平湖糟蛋中乙醇含量的方法。平湖糟蛋样品中的乙醇经蒸馏法充分提取,提取液在5.0mL重铬酸钾溶液(50g/L)和2.5mL硫酸溶液(50∶50,v/v)介质中于100℃水浴反应15min,恢复室温后采用分光光度法在585nm处测定吸光度值。该方法能较好排除基质效应影响,测定结果准确度高,乙醇含量在0.00~250.00g/kg范围内线性关系良好,相关系数大于0.999,加标回收率为96.2%~99.5%,精密度(relative standard deviation,RSD)为0.69%~2.28%。该方法操作简单、准确度高、回收率好,能准确地对糟蛋样品中乙醇进行定量检测。

食品中亚硝酸盐检测关键影响因素探究

目的:运用《食品安全国家标准食品中亚硝酸盐与硝酸盐的测定》(GB 5009.33—2016)第二法分光光度法对食品中亚硝酸盐进行检测,分析影响检测结果的关键因素。方法:将标准溶液和待测溶液在同等条件下进行测定,扩展标准曲线线性范围,将检测过程分为4个步骤,分别进行加标回收试验,结合氧化还原反应标准电极电势分析影响检测结果的关键因素。结果:亚铁氰化钾溶液久置后可能分解产生Fe^(3+),Fe^(3+)可氧化亚硝酸根导致检测结果偏低,其他溶液相对稳定。结论:GB 5009.33—2016中分光光度法稳定可靠,亚铁氰化钾溶液的稳定性是影响检测结果的关键因素。

铅酸蓄电池稀硫酸溶液中铁杂质含量检测方法的探讨

采用硫氰酸钾比色法、原子吸收分光光度法、邻菲啉分光光度法,对蓄电池中铁含量的检测方法与结果进行阐述、分析。并且,对不同检测方法的优、缺点进行比较。按实用性的原则,根据成本、效率、简繁程度等不同需求,选择合适的检测方法,在满足生产检测要求的同时,达到成本经济、时间短的目的。

碱性过硫酸钾消解紫外分光光度法测定水质总氮的不确定度评定研究

本文分析了使用碱性过硫酸钾消解紫外分光光度法测定水质总氮过程中的不确定度影响因素,比如标准曲线拟合、测量重复性等有可能对测定结果产生影响的因素,探索了减少干扰的方式方法,使实验室实验过程处于可控状态。

中空玻璃干燥剂钾交换率的测定——原子吸收分光光度法

介绍了一种中空玻璃干燥剂钾交换率测定的新方法。中空玻璃干燥剂经研磨、混合酸溶解后,消除待测溶液中铝对钾钠离子的干扰,采用原子吸收分光光度法测定溶液中氧化钾、氧化钠的含量后折算出钾交换率。

用铬(Ⅵ)-糗酸钾-茜素绿体系催化光度法测定痕量铬(Ⅵ)

基于酸性介质中溴酸钾氧化茜素绿的反应,提出了测定痕量铬(Ⅵ)的新催化光度法.方法检出限为 3.0×10^(-9)g/mL,可测铬(Ⅵ)量的范围为 0.01~0.24μge/mL,应用于测定电镀废水和电镀排放水中铬(Ⅵ).

痕量间苯二酚的KBrO_3-KBr紫外分光光度法测定

研究了HCl溶液中KBrO3 -KBr紫外分光光度法测定间苯二酚的条件 ,建立了测定痕量间苯二酚的方法。结果表明 ,在0.6mol/LHCl-4×10-5 mol/LKBrO3-6×10-4 mol/LKBr-6×10-4 mol/LKI溶液中测定间苯二酚 ,其线性范围为0.2～4.0mg/L ,表观摩尔吸光系数为2.34×104 L·mol-1 ·cm-1 ,Sandell灵敏度为0.0047μg/cm2。该法用于自制废水中间苯二酚的测定 。

丁基罗丹明B-高碘酸钾动力学光度法测定铑

报道了以铐催化高碘酸钾氧化丁基罗丹明B为基础的动力学测定痕量铑的方法,详细研究了动力学条件,建立了动力学光度测定痕量铑的新方法,铑浓度在0～180μg/L范围内与log(A_o/A)呈线性关系,检出限为2.84×10^(-7)g/L,该反应对Rh(Ⅲ)或丁基罗丹明B为一级反应,表观活化能为64.04kJ/mol.本方法用于某些催化剂中铑的测定,其相对标准偏差为1.76%～3.46%,回收率为96.8%～104.7%.

催化动力学光度法测定痕量钴(Ⅱ)

本法基于钴 (Ⅱ )对高碘酸钾氧化孔雀绿的催化作用 ,提出一种灵敏地测定痕量钴 (Ⅱ )的新方法。该方法线性范围在 0～ 0 8μg·2 5mL- 1 ,检测限为 2 1× 10 - 1 0 g·mL- 1 。测定出反应表现活化能Ea=37 94kJ·mol- 1 。此法用于茶叶、维生素B1 2 中钴的测定 。

镉-碘化物-吖啶红高灵敏显色反应及其分析应用

基于在稀磷酸溶液中，镉（Ⅱ）与碘化物和吖啶红（ＡＤＲ）的离了缔合反应，发展了一种高灵敏测定镉的分光光度法。当以试剂空白作参比，离子缔合物的最大吸收波长位于５８０ｎｍ处，摩尔吸光系数达５．６ × １０５Ｌ·ｍｏｌ－１·ｃｍ－１，Ｃｄ（Ⅱ）在０～８０ μｇ／Ｌ的浓度范围内符合比尔定律，方法有较好的选择性，可用于某些样品中痕量镉的测定。

派罗宁GS-高碘酸钾催化光度法测定痕量钌

依据钌对高碘酸钾氧化派罗宁GS(PGS)的催化反应 ,建立了催化动力学测定痕量钌的新方法。在最佳测定条件下 ,本法测定钌的线性范围为 2 5mL溶液中 0 0 5～ 2 0ng钌 ,检出限为 1 66pg/mL ,于 2 5mL溶液中 ,对 1 0ngRu 测定的相对标准偏差为 0 72 % (n =10 )。测定了催化反应的动力学参数 ,初步探讨了反应机理 ,并将所建立的新方法用于冶金产品及岩矿中钌的测定 ,其相对标准偏差为 0 96%～ 2 5 % ,标准加入回收率为 96 0 %～ 10 3 9%。