Solid Phase Extraction and Spectrophotometric Determination of Silver with 2-(2-Quinolylazo)-5-diethylaminoaniline as Chromogenic Reagent

 A new chromogenic reagent, 2-(2-quinolylazo)-5-diethylaminoaniline(QADEAA), was synthesized. A highly sensitive, selective and rapid method for the determination of silver was developed. It is based on the rapid reaction of silver (I) with QADEAA and the solid phase extraction of colored chelate using reversed-phase separation cartridge. At pH 6.5 in the presence of sodium dodecyl sulfonate (SDS), QADEAA reacts with silver to form a violet chelate in a molar ratio of 1:2 (silver to QADEAA). This chelate was enriched by solid phase extraction. The retained chelate can be eluted from the cartridge with ethanol. In ethanol medium, the molar absorptivity of the chelate is 1.36×10⁵ L·mol⁻¹·cm⁻¹ at 590 nm. Beer’s law is obeyed in the range 0.01–0.6 μg L⁻¹. The relative standard deviation for eleven replicate samples of 0.01 μg L⁻¹ level is 1.9%. The detection limit reaches the 0.02 μg L⁻¹ level. This method shows satisfactory results when used for the determination of silver in water. Correspondence: Department of Chemistry, Yuxi Teacher’s College, Yuxi, 653100, P.R. China. e-mail: hugiufena@163.com Received 19 August 2002; accepted 20 October 2002     

2-[2-(4-甲基喹啉)-偶氮]-5-二乙氨基苯酚固相萃取光度法测定水和食品中的镉

研究了新试剂2[2(4甲基喹啉)偶氮]5二乙氨基苯酚(QADP)与镉的显色反应。在pH为8.0的硼酸氢氧化钠缓冲介质中,TritonX100存在下,QADP与镉反应生成2∶1稳定络合物。体系最大吸收波长λmax=590nm,摩尔吸光系数ε=1.56×105L·mol-1·cm-1。样品中的镉用强阴离子交换固相萃取柱固相萃取预分离和富集后用该方法测定,结果令人满意。     

固相萃取光度法测定水样中的银

银是一种重要的环境元素,已被列为水质常规检测项目之一。本实验研究了氯磺酚偶氮硫代若丹宁[5-(2-羟基,4-磺酸基,5-氯苯-1-偶氮)-硫代若丹宁(HSCT)]与银的显色反应及C18固相萃取小柱对络合物的固相萃取,并基于此建立了一种用固相萃取光度法测定环境水样中μg／L级银含量的新方法。     

2-(2-喹啉偶氮)-1,5-苯二酚固相萃取光度法测定饮用水中铜的研究

根据新试剂2－（2－喹啉偶氮）－1，5－苯二酚（QADHB）与铜的显色反应及Waters Porapak Sep-Park固相萃取小柱对显色络合物的固相萃取，建立了一种测定水样中铜的新方法。在pH=4.0 HAc-NaAc缓冲介质中，溴化十六烷基三甲基铵（CTMAB）存在下，QADHB与铜反应生成2：1稳定络合物，该络合物可用Waters Porapak Sep-Park固相萃取小柱富集，用乙醇洗脱后用光度法测定，可测定水柱中μg/L级的铜。方法用于几种饮用水中铜的分析，结果令人满意。     

Spectrophotometric Determination of Microamounts of Ruthenium Using 2-(3,5-Dichloro-2-Pyridylazo)-5-Dimethylaminophenol and its Application

Binary component colour systems of spectrophotometric determination of Ru using heterocyclic-azo reagents have been reported, but their apparent molar absorptivities are low.     

2-(2-喹啉偶氮)-4-甲基-1, 5-苯二酚测定银的研究

合成了新试剂2-(2-喹啉偶氮)-4-甲基-1,5-苯二酚(QAMDHB),研究了其与银的显色反应.在pH=4.7的乙酸-乙酸钠缓冲介质中,QAMDHB与银反应生成2∶1的稳定络合物,λmax=558 nm,ε=5.8×104 L*mol-1*cm-1,银含量在0～1.6 mg/L内符合比耳定律.方法用于环境废水中银含量的测定,结果满意.     

8-羟基喹哪啶固相萃取光度法测定水样中的铁

研究了8-羟基喹哪啶与铁的显色反应，在pH为8．0的氯化氨-氨水缓冲介质中，在十六烷基三甲基溴化铵(CTMAB)存在下，8-羟基喹哪啶与铁反应生成3：1稳定的蓝紫色络合物，该络合物可被Waters Sep-Park-C18固相萃取小柱萃取，用乙醇洗脱后用光度法测定，络合物λmax=600nm。在此波长下其它金属离子的络合物无光吸收，对铁选择性很好，铁含量在0-5mg/L内符合比尔定律，方法用于水样中痕量铁的测定，结果令人满意。     

2-(2-喹啉偶氮)-5-二乙氨基苯甲酸固相萃取光度法测定环境水样中的镍

用2－（2－喹啉偶氮）－5－二乙氨基苯甲酸（QADEAB）与镍的显色反应及Waters Porapak^R Sep-Park固术萃取小柱对显色络合物的固相萃取，建立了测定水样中μg/L级镍的新方法。水样中的镍在pH=8.0的硼酸－磷酸二氢钾缓冲介质中和Tween 80存在下与QADEAB反应生成2：1稳定有色络合物，该络合物可用Waters Porapak^R Sep-Park固相萃取小柱富集，用乙醇洗脱后用光度法测定，可测定水样中μg/L级的镍。方法用于几种环境水样分析，结果令人满意。     

Study of Solid Phase Extraction Prior to Spectrophotometric Determination of Platinum with N-(3,5-Dimethylphenyl)-N′-(4-Aminobenzenesulfonate)-Thiourea

A highly sensitive, selective and rapid method for the determination of platinum based on the rapid reaction of platinum(IV) with N-(3,5-dimethylphenyl)-N′-(4-aminobenzenesulfonate)-thiourea (DMMPT) and the solid phase extraction of the Pt(IV)-DMMPT complex with C₁₈ membrane disks was developed. In the presence of pH = 3.8 buffer solution and cetyl trimethylammonium bromide (CTMAB) medium, DMMPT reacts with platinum to form a violet complex of a molar ratio of 1:3 (platinum to DMMPT). This complex was enriched by solid phase extraction with C₁₈ membrane disks, and an enrichment factor of 200 was obtained. The molar absorptivity of the complex is 9.51 × 10⁴ L · mol⁻¹ · cm⁻¹ at 755 nm, and Beer’s law is obeyed in the range of 0.01–3.0 μg mL⁻¹ in the measured solution. The relative standard deviation for eleven replicate samples of 0.01 μg mL⁻¹ level is 1.79%. The detection limit reaches 0.02 μg L⁻¹ in the original samples. This method was applied to the determination of platinum in water and soil samples. The relative standard deviations are 2.9–3.4%. The recoveries are 94–105%. The values of determination obtained agree with those of the ICP-MS method. The results are satisfactory.     

Spectrophotometric Determination of Mercury Using 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol

Abstract

Mercuric ion with 5-Br-PADAP forms a 1:2 complex at pH 8.0–10, which, with the addition of Triton X-100, has a molar absorptivity of 1.10 × 10⁵ at 565 nm. A method is described for the determination of mercury in industrial waste water and sludge.     

显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸与钯(Ⅱ)的显色反应研究

研究了显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸(CTZDBA)与钯(Ⅱ)的显色反应。结果表明,Pd(Ⅱ)与CTZDBA生成稳定的1∶2的紫红色配合物,其最大吸收波长为548 nm,配合物的表观摩尔吸光系数为9.32×104L.mol-1.cm-1,Pd(Ⅱ)质量浓度在0.08~0.8 mg/L范围内符合比耳定律。该方法可不经分离直接测定钯碳催化剂和钯纳米碳催化剂中的微量钯,测定结果与原子吸收法(AAS)基本相符。     

对磺酸基苯亚甲基硫代若丹宁固相萃取光度法测定烟草添加剂中的汞

合成了新试剂对磺酸基苯亚甲基硫代若丹宁(SBDTR),并用红外光谱、核磁共振氢谱和元素分析鉴定其结构。研究了SBDTR与汞的显色反应。在pH3.5的HAc NaAc缓冲介质中,吐温 80存在下,SBDTR与汞反应生成2∶1稳定络合物。该络合物可用WatersSep ParkC18固相萃取柱萃取,用乙醇洗脱后,在乙醇介质中用分光光度法测定,体系摩尔吸光系数为8.36×104L·mol-1·cm-1。汞含量在0～4μg/mL内符合比耳定律。本方法可用于烟草添加剂中汞含量的测定,结果满意。     

2-(2-喹啉偶氮)-1,5-二氨基苯固相萃取光度法测定痕量钯

根据2-(2-喹啉偶氮)-1,5-二氨基苯(QADAB)与钯的显色反应及MCI-GEL反相固相萃取小柱对显色络合物的固相萃取,建立了一种测定痕量钯的方法.在0.2～3.0 mol·L-1高氯酸介质中,溴化十六烷基三甲胺(CTMAB)存在下,QADAB与钯反应生成2:1稳定络合物,该络合物可被MCI-GEL反相固相萃取小柱萃取富集,富集的络合物用丙酮洗脱后用光度法测定,在丙酮介质中体系的最大吸收波长为600 nm,表观摩尔吸光率为9.63×104L·mol-1·cm-1.钯质量浓度在0.01～L 5 mg·L-1内符合比耳定律,方法用于几种实样中痕量钯的测定,测得回收率在86%～96%间.     

微波消解和固相萃取光度法测定氰化渣中痕量钯

根据 2_(2_喹啉偶氮 )_5_二甲氨基苯甲酸 (QADMAB)与钯的显色反应及C18固相萃取小柱对显色络合物的固相萃取 ,并结合微波消解样品 ,建立了一种测定氰化渣中痕量钯的方法。即在pH为 3 5的HAc_NaAc缓冲介质中 ,溴化十六烷基三甲胺 (CTMAB)存在下 ,QADMAB与钯反应生成 2 1稳定络合物 ,该络合物可被C18小柱萃取富集 ,富集的络合物用乙醇洗脱后用光度法测定 ,在乙醇介质中体系λmax=63 0nm ,ε=1 2 0× 1 0 5L·mol-1·cm-1。钯含量在 0 0 1～ 1 5mg L内符合比尔定律 ,方法用于氰化渣中钯含量的测定 ,结果令人满意。     

2-(2-喹啉偶氮)-5-二乙氨基苯胺光度法测定钴

合成了新试剂 2 (2 喹啉偶氮 ) 5 二乙氨基苯胺 (QADEAA) ,并研究了其与钴的显色反应 ,在pH为5 .5的磷酸盐缓冲介质中 ,在CTMAB存在下 ,QADEAA与钴反应生成 2∶1稳定络合物 ;用磷酸酸化后 ,在酸介质中 ,体系λmax=6 2 5nm ,ε =1 .4 6× 1 0 5L·mol-1 ·cm-1 。钴含量在 0 .0 1～ 0 .30mg/L内符合比尔定律。方法用于大米、猪肝及水样中钴含量的测定 ,结果令人满意     

3,5-二溴-PADAP 分光光度法测定微量离子的研究

系统研究了3,5-二溴-PADAP 在酸性介质中质子化后与 NO-2和 SCN- 形成三元离子缔合物的最佳条件.提出了测定微量 NO-2 的分光光度新方法,表观摩尔吸光系数 ε630=1.2×104L.mol-1.cm-1,缔合物组成比为 n(3,5-二溴-PADAP)∶n(NO2-)∶n(SCN-)=1∶1∶1.本法应用环境水体中微量的测定,与经典方法对照结果吻合.     

3,5—二溴—PADAP分光光度法测定微量NO2—离子的研究

系统研究了３,５－二溴－ＰＡＤＡＰ在酸性介质中质子化后与ＮＯ２和ＳＣ怙元离子缔合物的最佳条件。提出了测定微量ＮＯ２的光度新方法,表观摩尔吸光系数ε６３０＝１．２×１０＾４Ｌ·ｍｏｌ＾－１·ｃｍ＾－１,缔合物组成比为ｎ（３,５－ｆｇ ｉｔｈｄ－ＰＡＤＡＰ）：ｎ（ＮＯ２）：ｎ（ＳＣＮ）＝１：１：！。ｓｇ ｉｆ ｙｉｅｔｇｇｆｕｉｉ ｗｓｇ ｋ ｔｍｇ ｊｇ ＮＯ２ｒ ｉｍｐｇ,ｇｎ ｘ ｍａｗ ｙｙｉ     

Selective Spectrophotometric Determination of Palladium (II) With 2-(5-Bromo-2-Pyridylazo)-5-(Diethylamino)-Phenol

Abstract

A spectrophotometric study of the Pd(II) complex of a reagent 2-(5-Bromo-2-Pyridylazo)-5-(diethylamino)-Phenol (5-Br-PADAP) is presented. A violet complex is formed at pH 3.53, and shows maximal absorbance at 585 nm with molar absorptivity of 3.86 × 10⁴ 1. mol^?1 cm^?1. Beer's law is obeyed up to 50 μ of Pd(II). The method offers the advantages of simplicity, high precision, requires no extraction and is very selective, where 5.0 mg Pt(VI) and 0.3 mg Au(III) ions do not interfere.     

Rapid and Sensitive Spectrophotometric Determination of Hafuium(IV) With 2-(5-Bromo-2-Pyridylazo)-5-Diethylaminophenol

Abstract

Hafnium(IV) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in the pH range 3.3–11.0 to yield a sparingly soluble red-coloured chelate that can be dissolved with Triton X-100. Effect of initial pH of metal ion and order of addition of reagents was studied in detail. The 1:3 complex adheres to Beer's law over the concentration range 0.02–1.12 μg/ml of Hf(IV), has a molar absorptivity 1.33x10⁵ 1 mol^?1cm^?1, Sandell sensitivity 1.3 ng cm^?2, formation constant (log K) 11.94 and the method had a relative standard deviation of ± 1.5%. Effect of 60 diverse ions on the determination of hafnium(IV) was studied. This fairly selective method is the most sensitive so far reported for the spectrophotometric determination of hafnium(IV).