在二氧化碳气氛中溶剂浮选高碘蛋总碘量的吸光光度法

浮选法是在二氧化碳气氛中,以溴化十六烷三甲基铵（ＣＴＭＡＢ）为捕收剂,用溶剂浮选吸光光度法,对离子缔合物（ＣＴＭＡ＾＋Ｉ３＾－）的组成进行测定。试验表明,方法有较高的灵敏度,较好的准确性和重性现。     

以十二烷基苯磺酸钠浮选铑(Ⅲ)水合阳离子及其与钯(Ⅱ)、铂(Ⅳ)分离的研究

本文提出了一个浮选Rh(Ⅲ)水合阳离子的新方法。首先将Rh(Ⅲ)转化为水合阳离子,然后以十二烷基苯磺酸钠浮选,与仍处于氯络阴离子状态的Pd(Ⅱ),Pt(Ⅳ)分离,研究了影响浮选分离的各种因素。本文还考察了经水解、酸化预处理后,阳离子表面活性剂浮选PdCl_4~(2-)、PtCl_6~(2-)与Rh(Ⅲ)水合阳离子分离的效果。     

溶剂浮选-气相色谱/质谱法测定蔬菜中氨基甲酸酯类农药残留

建立了一种有效分离富集并榆测蔬菜中氨基甲酸酯类农药残留的方法,即采用溶剂浮选法(SS)对蔬菜中的氨基甲酸酯类农药残留进行分离富集.然后用气相色谱,质谱(GC/MS)进行检测.考察了浮选溶剂、试液pH、通气速度及浮选时间等因索对浮选效果的影响,得剑了优化浮选条件 对此条件下的浮选产物进行气相色谱/质谱检测,回收率为81.6%～97.8%,RSD为1.39%～2.65%,定量限(LOQ)为0.39-6.17 pg/kg.     

温敏性聚合物EOPO-K2HPO4双水相浮选高效液相色谱分离/富集食品中痕量的环丙沙星

建立了温敏性聚合物EOPO-K2HPO4双水相浮选技术,并结合HPLC-UV,分离检测了日常食物中的痕量环丙沙星(CIP).讨论了盐浓度、EOPO浓度、pH值、浮选时间、浮选速率对浮选率的影响,并采用响应曲面法(RSM)对实验条件进行了优化.在最优条件(K2HPO4浓度为55％(w/w)、浮选时间为50 min、浮选流速为28 mL/min)下,CIP的萃取率达到了98.9％.在二次萃取中,随着温度的诱导,CIP的萃取率高达87.6％,且相对标准偏差(RSD)在0.3％ ～0.7％.双水相组分被成功回收利用达到两次以上.     

双水相浮选过程中青霉素的分离行为

基于双水相浮选技术(ATPF)分离富集水相中青霉素的方法,研究了双水相浮选过程中青霉素的分离行为.在常温下,2.5 g/L青霉素水溶液300 mL、初始pH 7、(NH4)2SO4浓度350 g/L、浮选溶剂为50%(w/w)PEG1000水溶液10 mL条件下,分别研究了青霉素在双水相浮选过程中的动力学行为和分离后的...     

硝酸钠-碘化钾-氯化十六烷基吡啶-水体系浮选分离汞(Ⅱ)的研究

研究了硝酸钠 碘化钾 氯化十六烷基吡啶 水体系浮选分离汞 (Ⅱ )的行为及其与常见离子分离的条件。控制pH 4 .0 ,在硝酸钠存在下 ,Hg(Ⅱ )可被碘化钾 氯化十六烷基吡啶 水体系浮选 ,而Zn(Ⅱ )、Ni(Ⅱ )、Co(Ⅱ )、Mn(Ⅱ )、Fe(Ⅱ)、Al(Ⅱ )等离子在该体系中不被浮选 ,从而实现了Hg(Ⅱ )与这些常见离子之间的定量分离     

硫氰酸铵-溴化十六烷基吡啶-水体系浮选分离汞

研究了氯化钠存在下硫氰酸铵-溴化十六烷基吡啶-水体系浮选分离Hg(Ⅱ)的行为及其与常见离子分离的条件。结果表明:pH 5.0,在1.0 g氯化钠存在下,当0.1 mol.L-1硫氰酸铵溶液0.5 mL,1.0×10-2mol.L-1溴化十六烷基吡啶溶液1.0 mL时,Hg(Ⅱ)可被此体系定量浮选,而Cd(Ⅱ)、Ni(Ⅱ)、Co(Ⅱ)、Mn(Ⅱ)、Fe(Ⅱ)、Al(Ⅲ)等离子在此体系中不被浮选,从而实现了Hg(Ⅱ)与这些常见离子之间的定量分离,对合成水样中微量Hg(Ⅱ)进行的定量浮选分离测定,测得平均回收率为100.5%。     

氯化钠-硫氰酸铵-十六烷基氯化吡啶(钅翁)-水体系浮选分离锌(Ⅱ)

研究了氯化钠-硫氰酸铵-十六烷基氯化吡啶(钅翁)-水体系浮选分离锌(Ⅱ)的行为及其与常见离子分离的条件. 结果表明,在1.0 g固体NaCl存在下,当硫氰酸铵(0.1 mol/L)和十六烷基氯化吡啶(钅翁)(0.01 mol/L)溶液的用量均为2.0 mL时,控制pH值为4.0,Zn(Ⅱ)可被该体系浮选,而Cd(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)、Mn(Ⅱ)、Fe(Ⅱ)、Al(Ⅲ)不被浮选,可实现Zn(Ⅱ)与这些离子的定量分离,对合成水样的定量浮选分离,结果满意.     

混酸体系中31种金属离子的浮选行为

在总浓度为0.17～3.4N的HCl-HNO_3(〔HCl〕:〔HNO_3〕=2.4:1)体系中,以(18～60)×10~(-5)M的CPC为捕集剂,对(2.755～28.69)×10~(-5)M的31种金属离子进行了浮选,表明Ir(Ⅳ)、Pt(Ⅳ)、Ge(Ⅳ)、Sn(Ⅳ)、Bi(Ⅲ)、Au(Ⅲ)、T1(Ⅱ)、Pd(Ⅱ)、Sn(Ⅱ)可浮选95％以上,而Cr(Ⅵ)、Ti (Ⅳ)、Zr(Ⅳ)、Ga(Ⅲ)、In(Ⅲ)、Fe(Ⅲ)、Sb(Ⅲ)、Al(Ⅲ)、Mn(Ⅱ)、Fe(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Zn(Ⅱ)、Cd(Ⅱ)、Pb(Ⅱ)浮选率低于20％或几乎不浮选,Ru(Ⅱ)、Rh(Ⅱ)、Ir(Ⅱ)、Hg(Ⅱ)、Ag(Ⅰ)、TI(Ⅰ)部分被浮选。与HCl体系的浮选结果进行了比较,发现贵金属的浮选率和选择性在HCl-HNO_3体系中更好。进行了Au(Ⅲ)、Pt(Ⅳ)、Pd(Ⅱ)与Zn(Ⅱ)、Cd(Ⅱ)、Hg(Ⅱ)、Sb (Ⅲ)的分离试验,结果令人满意。     

在NaNO3存在下浮选CuSCN间接测定抗坏血酸

建立了浮选CuSCN间接测定抗坏血酸(Vc)的方法。研究表明,在NaNO3存在下,Cu(Ⅱ)被抗坏血酸还原生成的Cu(Ⅰ)与SCN-形成CuSCN沉淀而被浮选。结果表明,Vc量在2.64~15.8 mg/L范围内与CuSCN的浮选率呈良好的线性关系,回归方程为:E/%=6.008ρ-3.673,r=0.9962。此方法可用于水果和药片中Vc量测定。     

Potentiometric study of reaction between periodate and iodide as their tetrabutylammonium salts in chloroform. Application to the determination of iodide and potentiometric detection of end points in acid-base titrations in chloroform

A potentiometric method for the titration of tetrabutylammonium iodide (TBAI) in chloroform using tetrabutylammonium periodate (TBAPI) as a strong and suitable oxidizing reagent is described. The potentiometric conditions were optimized and the equilibrium constants of the reactions occurring during the titration were determined. The method was used for the determination of iodide both in chloroform and aqueous solutions after extraction into chloroform as ion-association with tetraphenylarsonium. The reaction between TBAPI and TBAI was also used as acid indicator for the potentiometric detection of end points of acid-base titrations in chloroform.     

Third Order Derivative Spectrophotometry Determination of Mercury (II) as the Ternary Complex with Iodide and Pyronine G

Abstract

This paper describes a third order derivative mole cular absorption spectrophotometric procedure for the deter mination of traces of mercury based on the formation of ternary ion-association complex by reaction of mercury with pyronine G in the presence of iodide. The pink coloured ternary ion-association complex is readily formed in the pH range 1–7 and remained stable for 24 h. after stabilization with gelatin. The influence of various instru mental parameters and reaction conditions for maximum color development are discussed. The few interfering ions can be masked by the addition of appropriate reagent solutions.     

Ion Association Between Hexaamminecobalt (III) Ion and Monovalent Anions in Methanol-Water Mixtures from 10 to 50°C

The conductivities of chloride, bromide, iodide, nitrate, and perchlorate of hexaamminecobalt(III) complex were measured in 10-80 wt.% methanol-water mixtures at varying temperatures from 10 to 50°C. The ion association constants were estimated by analyzing conductivity data in terms of the Robinson-Stokes equations. Ion-association constants calculated for all complex salts in methanol-water mixtures increased, depending on the percentage of methanol. This was equivalent to the ion-association constants increasing with a decrease in the the dielectric constant of the mixtures. K _A values increased with increasing temperature for the chloride, bromide, and iodide of [Co(NH₃)₆]³⁺. It was observed that these values indicated some disorder, dependent on the temperature, for nitrate and perchlorate. Thermodynamic parameters (Gibbs' free energy, entropy and enthalpy of ion association) were estimated from the temperature dependence of the ion-association constant. The limiting molar conductivities of complex ion and monovalent anions in the mixed solvents were determined from our experimental data by using the Kohlraush equation.     

Study on the colour reaction of Te-KI-RhB system in the presence of PVA-OP

A new supersensitive spectrophotometric method for the determination of tellurium (IV) has been developed which is based on the formation of an ion-association complex with potassium iodide and rhodamine B (RhB) in the presence of polyvinyl alcohol (PVA) and polyethylene glycol octyl phenyl ether (OP). The molar absorptivity at 560 nm is 2.8 × 10⁶ 1 mol^–1 cm^–1. Beer's law is obeyed over the range of 20–70 ng/ml Te. The method has been applied successfully to determine tellurium in alloy, steel and some other samples.     

Calmagite as a spectrophotometric reagent for aluminium

Calmagite is proposed as a sensitive spectrophotometric reagent for aluminium, (570mmu) = 42000. After aqueous phase reaction at pH 8.6, the metal-reagent complex is extracted into chloroform by formation of an ion-association complex with a quaternary ammonium salt. The method is free from interference by common anions, and cationic interferences may be eliminated by the use of cyanide and EDTA as masking agents.     

Atomic absorption spectrophotometric determination of microgram quantities of copper in tea after solvent extraction

An atomic absorption spectrophotometric method is described for determining trace amounts of copper in tea. The method is based on the solvent extraction of the metal as tetraiodocuprate (I), from 2 M HCl solutions of tea samples which contain 12% (w/v) KI, into methylisobutyl ketone. The organic extracts, containing the ion-association complex of copper are atomized into an air-acetylene flame. The limit of detection is 1.14 micrograms g-1 Cu.     

〔I2Br〕- 与某些碱性三芳基甲烷染料的水相显色反应及其应用于碘的分光光度测定

研究〔I2Br〕-络阴离子与乙基紫、结晶紫、维多利亚蓝4R等碱性三芳基甲烷染料在聚乙烯醇存在下的离子缔合反应的条件、分光光度特征和分析化学性质。结果表明,在稀磷酸介质中,当形成上述离子缔合络合物时,溶液均发生明显的颜色变化。不同染料体系的摩尔吸光系数在2.6×104～6.2×104L*mol-1*cm-1之间,以乙基紫体系灵敏度最高。碘离子浓度在0～1.6mg/L（乙基紫体系）、0～1.4 mg/L（结晶紫体系）和0～0.8 mg/L(维多利亚蓝体系)符合比耳定律,可用于水相直接显色测定碘离子。方法也有良好的选择性,较大量的其他卤离子、一些无机酸根以及一定量的常见金属离子不干扰。用于海带、紫菜和黄豆中碘离子的测定,结果较为满意。     

铜(Ⅱ)-硫氰酸盐-乙基紫-微乳液分光光度法测定钢样中的微量铜

在非离子型微乳液(OP/n-C5H11OH/n-C7H16/H2O)存在下,Cu2+与硫氰酸盐形成络阴离子[Cu(SCN)4]2-,在pH 3.6乙酸盐缓冲溶液中,该络阴离子再与乙基紫(EV)形成吸附型离子络合物,该络合物的组成为[Cu(SCN)4]2-:EV=1:2,最大吸收波长为660nm,表观摩尔吸光系数ε660为1.08×l05L.mol-1.cm-1,Cu2+含量在1.7～18.0μg/50 mL范围内符合比尔定律,检出限为0.5μg/50 mL,用该方法测定了钢中的铜,相对标准偏差小于2%。     

Substoichiometric determination of zinc with thiocyanate and brilliant green

A method for the determination of microgram amounts of zinc has been developed. This is based on the substoichiometric extraction of its ion-association complex with brilliant green into benzene from thiocyanate solution.     

Indirect determination of cyanide in water by atomic-absorption spectrophotometry

An indirect method for determination of trace cyanide in water by atomic-absorption spectrophotometry is described. Cyanide forms a stable complex anion with Pd in alkaline solution. This complex anion can form an ion-association complex with tetra-alkylammonium ions which can be extracted into n-butyl alcohol with an efficiency higher than 90%. The extract can be analysed directly for palladium (and hence indirectly for cyanide) by flame atomic-absorption spectrophotometry. The detection limit for cyanide by this method is 0.1 mug ml in the n-butyl alcohol extract. Beer's law is obeyed for 0.13-9 mug of CN(-) per ml of n-butyl alcohol. Several foreign ions do not interfere.