Spectrophotometric Determination of Chlorprothixene with Eriochrome Cyanine R

 Two spectrophotometric methods are described for the determination of chlorprothixene (CPT). The first method is based on the extraction of the ion-association compound of CPT with eriochrome cyanine R (ECR) into butanol. The extracted compound in the organic solvent obeys Beer’s law in the range 5–80 μg mL ⁻¹. The second method is based on the measuring of the absorbance of the aqueous solution of the compound of CPT with ECR in presence of methylcellulose. Conformity with Beer’s law was evident in the range 0.7–10 μg mL ⁻¹ of chlorprothixene. The methods were applied for the determination of chlorprothixene contents in pharmaceuticals. Received July 30, 1998. Revision July 20, 1999.     

Spectrophotometric determination of titanium with Chrome Azurol S (or Eriochrome Cyanine R) in the presence of some cationic surfactants

A new sensitive spectrophotometric method for titanium determination, based on the ternary Ti-Chrome Azurol S (CAS)-cetyltrimethylammonium (CTA) system, was developed. The molar absorptivity is 7.3 × 10⁴ liters mol^?1 cm^?1 at λ_max = 565 nm. The maximum absorbance is attained in 5 min at pH 1.3 ± 0.1 and at CAS and CTA concentrations of 1.5 × 10^?4 and 5 × 10^?4M, respectively. Zirconium and hafnium in the presence of ascorbic acid are the only interfering metals. Hydrogen peroxide and EDTA interfere with the titanium determination as well. The proposed method was applied to the determination of titanium (about 1 × 10^?2%) in aluminum metal. The method, based on the Ti-Eriochrome Cyanine R-CTA system, is similar to the above method. Among other cationic surfactants, cetylpyridinium chloride (CP) and zephiramine were examined. The color effects when using CP, and especially zephiramine, are worse than in the presence of CTA.     

羊毛铬菁R分光光度法测定土壤中的活性铝

利用羊毛铭菁R作显色剂测定土壤中的铝,具有方法简单,快速和测定精度较高等优点,曾被用于测定西南地区受酸雨影响之土壤中的铝和不同体系中各种形态的铝。本法最小检测量为6μgAl/l。回收率为94～106%。     

Determination of Chromium(III) with Eriochrome Cyanine R by Fourth-Derivative Spectrophotometry

Summary

A fourth-derivative spectrophotometric determination of chromium(III) with Eriochrome Cyanine R (ECR) was described. The method was based on measuring the fourth-derivative value (D₄) at 545 nm. The experimental and instrumental variables (wavelength range, scan speed, band width and order of derivative) were optimized. Under the optimum conditions, the calibration graph fit the equation d⁴ A/d⁴ = 3.75 × 10⁵ [Cr(III)] + 0.003 (r=0.9991) and have a relative standard deviation of 1.19%. The method was valid for concentrations between 20 ng/ml and 80 ng/ml of chromium(III). The molar ratio of the formed complex was 1:2 (M:L). The proposed method was successfully applied to the determination of chromium in steel.     

Spectrophotometric determination of iron(III) with chrome azurol s or eriochrome cyanine r and some cationic surfactants

Sensitive spectrophotometric methods for the determination of iron(III), based on ternary complexes with a triphenylmethane reagent, chrome azurol S (CAS) or eriochrome cyanine R (ECR), and cetyltrimethylammonium (CTA) or cetylpyridinium (CP) ions, are described. For the system Fe—CAS—CTA, the molar absorptivity is 1.35 × 10⁵ l mol^-1 cm^-1 at 645 nm; for Fe—ECR—CTA it is 1.28 × 10⁵ l mol^-1 cm^-1 at 635 nm. Maximum absorbance is attained (at about pH 4) when the molar ratio (to iron) or CAS or ECR is about 20 and that of CTA or CP is 60–80. Citrate, tartrate, oxalate and EDTA interfere. Interference by metals (e.g. Be, Al, Ga, In, Sc, Zr, Th) can be eliminated by preliminary extraction of iron(III) as thiocyanate complex. The method was successfully applied to determining traces of iron in analytical-grade sodium hydroxide.     

Complex formation of iron (III) with chrome azurol s

The complex formation of iron(IIl) with 3”-sulpho-2”,6”-dichloro-3,3'-dimethyl-4'-hydroxy-fuchson-5,5'-dicarboxylic acid (chrome azurol S) was studied by spectrophotometric, conductometric and potentiometric methods. The pure tetrabasic acid of the ligand was prepared from the impure trisodium salt (commercially availalile), and the dissociation constants of the ligand were redetermined. At 20° ± 1° and in the presence of 0.10 M potassium chloride the dissociation constants were: pk₁ < 0.0, pk₂ = 2.25 ± 0.05, pk₃ = 4.71 ± 0.03 and pk₄ = 11.81 ± 0.03.In the pH range 2–4, four complexes were detected (the absolute stability constants at 20° ± 5° and at an ionic strength of 0.10 M are given in parentheses) : a ring-formed dimer complex [Fe(H₂O)₂]₂Ch₂^2- (log k_2,2 = 36.2); a monomer of composition [Fe(H₂O)₄]HCh or [Fe(H₂O)₄]HCh^- (the absolute stability constant was calculated as log k_1,1 = 15.6 for the latter composition); a complex [Fe(H₂O)₄]₂Ch²⁺ (log k_3.1=20.2) and, finally, a complex of composition [Fe(H₂O)₂]H_xCh₂^x-5 (the value of x being unknown). In addition, hydroxo complexes of the dimer were formed at higher pH values.     

Spectrophotometric determination of trace uranium with Eriochrome Azurol B and Chrome Azurol S in the presence of the cationic surfactant Septonex

Procedures for the spectrophotometric determination of UO(2+)(2) with Eriochrome Azurol B and Chrome Azurol S in the presence of the cationic surfactant Septonex have been developed from studies of the complex equilibria in solution, and simplex and single-factor optimization. They are suitable for the determination of UO(2+)(2) in drinking, surface and waste waters after prior separation with tri-n-octylamine in benzene or Freon 113 from 4M hydrochloric acid and stripping with 0.3M hydrochloric acid.     

Complex formation of copper(II) with chrome azurol s

The complex formation of copper(II) with chrome azurol S (CAS) was studied by spectrophotometric and potentiometric methods. In the pH range 5–7, two complexes with the composition Cu(H₂O)₂HCAS- and (Cu(H₂O)₂)₂CAS were detected; the stability constants were calculated to be log K = 4.02 ±0.05 and log K = 13.7±0.1, respectively (at 25° and ionic strength 0.1 (KCl)). A comparison is made between the copper(II)-CAS and iron(III)-CAS systems.     

新试剂5-(4-氯苯基偶氮)-8-苯磺酰氨基喹啉光度法测定微量铜

在 p H 8.5的 Na2 B4 O7- HCl介质及有氯化十六烷基吡啶 ( CPC)存在时 ,室温下铜 ( )与 5 - ( 4 -氯苯基偶氮 ) - 8-苯基磺酰氨基喹啉 ( CPBSQ)迅速反应 ,生成络合比为 1∶ 3的有色络合物。研究了反应的最佳条件 ,建立了一个测定 Cu( )的光度分析新方法。Cu( )的浓度在 0～ 1 4.0 μg/2 5 m L 范围内符合比耳定律 ,其摩尔吸光系数为 8.1 2× 1 0 4 L· mol- 1· cm- 1。方法用于面粉、茶叶及奶粉中铜的测定 ,其相对标准偏差为 0 .5 8%～ 1 .2 % ,标准加入回收率为 95 .5 %～ 1 0 4 .5 %。     

Polarographic and Voltammetric Study of the Sc(III)-Acid Chrome Blue K Complex and Determination of Trace Scandium

Abstract

A new system of polarographic adsorptive wave for determining trace scandium was proposed. In 0.2 mol/L NH₄OAc, the Sc(III)- ACBK [1,8- dihydroxy- 2- (2- hydroxy- 5- sulfo- 1- phenylazo)- 3,6- disulfo- naphthalene, called acid chrome blue K] complex emerged a sensitive adsorptive complex wave(Ep′ = -0.67V). The molar ratio of Sc(III) to ACBK in the complex was established as 1: 2 and the apparent stability constant β₂ = 2.7 × 10¹⁵. But for Y(III), the molar ratio was 1: 1 and β = 1.5 × 10⁵. Because of the particularity of Sc complex, the sensitivity and the selectivity of determination Sc are much better than that of other rare earth ions. The detection limit is 1.1 × 10^?7 mol/L for oscillopolarography and 2.0 × 10^?8 mol/L for adsorptive stripping voltammetry.     

Spectrophotometric determination of samarium(III) with chrome azurol S in the presence of cetylpyridinium chloride

A sensitive, simple method for the determination of trace amounts of samarium by spectrophotometry is described based on the formation of the samarium-chrome azurol S (CAS) complex in micellar medium. The molar absorptivities of the complexes at pH 7.5 at 505 nm were 3.6x10(4) and 1.4x10(5) l mol(-1) cm(-1) for water media and cetylpyridinium chloride (CPC), respectively. Beer's law is obeyed from 0.05-2 mg l(-1) of samarium at 505 nm as Sm-CAS-CPC complex. Optimal conditions such as reagent amounts, and pH for the samarium determination were reported. The effects of foreign ions were also investigated. The proposed method was successfully applied to the determination of samarium contents in synthetic samples.     

Ir(Ⅳ)-KIO4-偶氮氯膦-PA催化分光光度法测定痕量铱的研究

在酸性介质中，高碘酸钾使显色剂偶氮氯膦－PA的褪色反应在痕量铱的催化作用下才能实现，其褪色度与铱浓度有良好的线性关系，研究了此反应的最佳条件，提出了在水相中直接测定痕量铱的催化分光光度分析法，方法检出限可达0．01ug/10mL，铱含量在0．03－0．45ug/10mL范围内符合比尔定律，此法灵敏度高，简便易行快速，选择性好。     

Spectrophotometric Determination of Sulfate Ion Through Copper(II)-azide System

Abstract

An indirect and alternative method for the determination of sulfate ion has been established by spectrophotometry. The procedure is based on the formation of copper(II) monoazido species, in water/acetone medium, in which a discoloration effect of system is caused by sulfate presence. In the recommended conditions, sulfate ions can be determined in the concentration range from 40 to 5000 mg/l (ppm), at 375 nm, in natural samples of waters. The best experimental conditions were determined analysing the different factors involved. Studies about the formation equilibria of the CuN₃ ⁺ and CuSO₄ species were realized in water and their respective stability constants (β₁ = 225 M^?1 and 7.15 M^?1) were determined by spectrophotometry at 25.0° C and ionic strength 1.0 M (NaClO₄). Equilibrium investigations were also made in presence of acetone. Additional studies on the ternary system Cu(II)/N₃ ^?/SO₄ ^2-) indicated some evidences of mixed complexes.     

Determination of (S)-(-)-cathinone and its metabolites (R,S)-(-)-norephedrine and (R,R)-(-)-norpseudoephedrine in urine by high-performance liquid chromatography with photodiode-array detection.

A high-performance liquid chromatographic (HPLC) procedure with photodiode-array detection (DAD) is described for the determination of (S)-(-)-cathinone (S-CA) and its metabolites (R,S)-(-)-norephedrine (R-NE) and (R,R)-(-)-norpseudoephedrine (R-NPE) in urine. Extraction and clean-up of 1-ml urine samples were performed on a cyano-bonded solid-phase column using (+/-)-amphetamine as internal standard. The concentrated extracts were separated on a 3-microns ODS-1 column with acetonitrile-water-phosphoric acid-hexylamine as the mobile phase. Peak detection was done at 192 nm. The detection limits for S-CA and R-NE/R-NPE in urine were 50 and 25 ng/ml, respectively. The differentiation of the enantiomers of cathinone and norephedrine was achieved by derivatization with (S)-(-)-1-phenylethyl isocyanate to the corresponding diastereomers followed by HPLC-DAD on a 5-microns normal-phase column. The R and S enantiomers of norpseudoephedrine were determined by gas chromatography-mass spectrometry after on-column derivatization with (S)-(-)-N-trifluoroacetylprolyl chloride. Following a single oral dose of 0.5 mg/kg of S-CA, the concentrations found in urine ranged from 0.2 to 3.8 micrograms/ml of S-CA, from 7.2 to 46.0 micrograms/ml of R-NE and from 0.5 to 2.5 micrograms/ml of R-NPE.     

2-(2-喹啉偶氮)-1,5-苯二酚光度法测定钴的研究

钴是人体生命活动不可缺少的重要元素 ,痕量钴的测定具有重要意义。吡啶偶氮类试剂、苯并噻唑偶氮类试剂和 8-氨基喹啉类试剂用于钴的测定已有不少报道 ,但是用 2 -氨基衍生物作钴的显色剂的研究报道较少。我们合成了新试剂 2 - ( 2 -喹啉偶氮 ) - 1 ,5 -苯二酚 ( QADHB) ,并研究了其和钴的显色反应 ,方法用于维生素 B12 针剂及烟草样品中钴含量的测定 ,结果满意     

微乳液--1-(2-吡啶偶氮)-2-萘酚体系测定Co(Ⅱ)

The spectrohpotometric determination of Co(Ⅱ) was studied with 1-( 2 -pyridylazo)-2-naphthol in the sodium dodecyl sulphate/n-heptane/water micr oemulsion medium.The apparent molar absorptivity is 1.84×10⁴ L^.mol -1^.cm^-1 at 575 nm.Beer's law is obeyed in the range of 0～ 50 μg/25 mL for Co(Ⅱ).     

微乳液增稳1-(2-吡啶偶氮)-2-萘酚光度法测定汽油中痕量抗静电剂环烷酸钴

本文研究了以微乳液为介质时钴与PAN的显色反应,该体系在570nm处有最大吸收,其表观摩尔吸光系数为2.2×10~4L·mol~(-1)·cm~(-1),钴量在0～50μg/25ml范围内符合比耳定律。该法适用于汽油中环烷酸钴的测定。     

5-(对-甲基苯基偶氮)-8-氨基喹啉分光光度法测定铝合金中微量铜

本文研究了5-(对-甲基苯基偶氮)-8-氨基喹啉(p-MPAQ)分光光度法测定微量铜(Ⅱ)的条件。在阳离子表面活性剂CTMAB存在下,于pH9.0～10.0的缓冲介质中,铜与p-MPAQ形成1:1的棕红色配合物,其表观摩尔吸光系数ε_(547)为3.62×10~4L·mol~(-1)·cm~(-1),Aλ高达117nm,铜量在0～13μg/10mL范围内服从比尔定律。采用氟化钠作掩蔽剂,可不经分离,直接测定铝合金中的微量铜。