共查询到20条相似文献,搜索用时 15 毫秒
1.
溴酸钾氧化酸性铬蓝K催化光度法测定痕量铜的研究 总被引:10,自引:3,他引:10
研究了在稀硫酸介质中,痕量铜催化溴酸钾氧化酸性铬蓝K的褪色反应,建立了一种高灵敏,高选择性测定痕量铜的新方法,方法的线性范围为0.0012~0.14mg/L,检出限为4.2×10^-7g/L,用于水,茶叶和粮食中铜的测定,结果满意。 相似文献
2.
A sensitive catalytic method is developed for the spectrophotometric determination of oxalic acid. The procedure is based on the effect of oxalate on the oxidation of Victoria blue B by dichromate in dilute sulfuric acid medium. The reaction is quantitatively estimated by measuring the decrease in absorbance of Victoria blue B at the maximum wavelength of 610nm after quenching the reaction with tap water. The factors effecting the sensitivity and reproducibility of the reaction were studied. The method is not interfered with by foreign species generally associated with oxalate and oxalic acid. The described method is simple, specific, inexpensive and suitable for oxalic acid concentrations of between 0.06 and 9.0µgmL–1. It was validated with satisfactory results by determining oxalic acid content in water extracts from plant materials such as spinach and Lathyrus sativus. 相似文献
3.
4.
A kinetic method is presented for the determination of Cu(II) in water. It is based on the catalytic effect of Cu(II) on
the oxidation of mercaptosuccinic acid by chromate in acidic media. The extent of the reaction is followed spectrophotometrically
at 345 nm and pseudo-first order rate coefficients are determined as a function of catalyst concentration. The optimum operating
conditions regarding ionic strength, temperature and concentration of reagents were established. Interference by several ionic
species was studied and the effects of Fe(III) and Pb(II) were suppressed by complexation with pyrophosphate. Calibration
lines were obtained for both low (30–640 μg · l−1) and high (640–1500 μg · l−1) catalyst concentrations. The relative standard deviation for 625 μg · l−1 Cu(II) is 6.1% (n = 5). The detection limit is 22 μg · l−1. The method was applied to real samples of river water of the mining region of Baia-Mare, Northern Romania. The results were
compared to those obtained by an officially standardized AAS method. Good agreement was attained. The method is inexpensive,
fairly rapid and sensitive. Moreover, its working range covers the exact range of concentrations usually encountered in the
mentioned geographic area.
Received July 28, 2000; accepted December 10, 2001; published online June 24, 2002 相似文献
5.
6.
高碘酸盐氧化耐尔蓝动力学光度法测定锇 总被引:3,自引:0,他引:3
在硫酸介质和热水浴中 ,Os( )对高碘酸盐氧化耐尔蓝有催化作用。研究了反应速率对酸度、浓度、温度和离子强度的依赖关系 ,采用 0 .0 1 0mol/ L硫酸 ,反应的灵敏度随温度升高而增大 ,反应速率对反应混合物的离子强度依赖较小。线性范围为 0~ 0 .2 5μg/ 2 5m L;检出限为 8.0 2× 1 0 -5 μg/ m L;对质量浓度为 0 .1 0 μg/ 2 5m L 的 Os( )测定的相对标准偏差为 1 .0 2 % ( n=1 1 ) ;导出了催化反应的动力学方程 ;探讨了反应机理。4 0 0倍量以上常见金属离子不干扰锇的测定 ,1 0倍量以上的 Ru( )、Fe3 +有干扰。本法已用于贵金属冶金样品中锇的测定。 相似文献
7.
Theodosios S. Sikalos Yannis M. Arabatzis Mamas I. Prodromidis Panayotis G. Veltsistas Miltiades I. Karayannis 《Mikrochimica acta》2000,135(3-4):197-201
In this work a kinetic spectrophotometric method for the determination of trace amounts of vanadium is presented. The method
is based on the catalytic effect of the vanadium(V) on the reaction between diphenylamine (DPhA) and hydrogen peroxide in
a concentrated solution of formic acid. The formation of the deep-blue oxidation product is followed by a filter spectrophotometer,
equipped with an optical fiber assembly, on line with a PC provided with the suitable software. The measurements were taken
at 583 nm, with an immersed type cell of 1 cm light path length. The optimization of the operating conditions regarding concentrations
of the reagents, temperature and interferences are also investigated. The working curve is linear over the concentration range
0.40–4.0 μg/ml vanadium(V). The relative standard deviation for a standard solution of 0.6 μg/ml of vanadium is 0.5% (n = 5).
The proposed method proved highly sensitive, selective and relatively rapid for the assay of vanadium, at low level of 0.40 μg/ml
without any pre-concentration step. The method was applied to alloys and cosmetics samples. The results were compared to those
received with a reference method. Good agreement was attained, with a mean error of 0.5%.
Received February 25, 2000. Revision May 15, 2000. 相似文献
8.
A novel kinetic spectrophotometry for the determination of trace aluminum is described based on the catalytic activity of Al3+ on the redox reaction between methylene blue (MB) and hydrogen peroxide in acetate buffer (pH 3.8). The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dye at the maximum absorption wavelength of 670nm. The variables that affected the reaction rate were fully investigated, and the optimum conditions were established. Aluminum can be determined in the range of 0–80ngmL–1 with a detection limit of 1.0ngmL–1. The relative standard deviation for 10 replicate determinations of 40ngmL–1 aluminum is 0.9%. The method was used to determine aluminum in tap water and biological samples and produced satisfactory results.Received December 18, 2002; accepted May 5, 2003
published online August 22, 2003 相似文献
9.
A simple and sensitive kinetic spectrophotometric method is described for the determination of micro amounts of ammonia.
The method is based on the inhibiting effect of ammonia on the oxidation rate of aqua ethylenediamine-tetraacetate chromium(III)
[Cr(HEDTA)(H2O)] with N-bromo succinimide (NBS) to yield chromium(VI). The reaction was followed spectrophotometrically by measuring the
rate of change in absorbance with time at 365 nm, which is the maximum absorption wavelength of chromium(VI). Using the recommended
procedure, ammonia can be determined up to 153 μg ml−1 with a linear calibration graph and a detection limit of 0.09 μg ml−1. The method was successfully applied to the determination of ammonia in waste water samples. Recovery experiments for the
analyzed samples were 97–100% with relative standard deviation, Sr (%) of ≤ 2.9% indicating high accuracy and precision of
the proposed method. The interference of various cations and anions in the determination of ammonia was investigated.
Received March 30, 2001 Revision September 3, 2001 相似文献
10.
用金钨杂多酸和耐尔蓝光度法测定纳克量金 总被引:3,自引:2,他引:3
在阿拉伯胶存在下,金与钨酸钠和耐尔蓝(NB)形成离子缔合物,它的最大吸收位于580nm,表观摩尔吸光系数ε值为2.38×10^7L·mol^-1·cm^-1,体系至少稳定24h。金量在0 ̄4.4μg/L范围内服从比尔定律,检测限(3σ)为0.069μg/L(n=12),对4.0μg/L Au(Ⅲ)测定的相对标准偏差为1.9%(n=11),离子缔合物的摩尔比为Au(Ⅲ):NB=1:3。考察了40多种 相似文献
11.
Soledad García Concepción Sánchez-Pedreño Isabel Albero Concepción García 《Mikrochimica acta》2001,136(1-2):67-71
Two flow injection (FI) spectrophotometric methods are proposed for the determination of diclofenac (DCF) or mefenamic acid
(MF) in bulk samples and pharmaceuticals. Both methods are based on the reaction of DCF or MF with potassium ferricyanide
in a sodium hydroxide medium. The absorbance of the orange products obtained is measured at 455 nm for DCF and 465 nm for
MF. The corresponding calibration graphs are linear over the range 0.20–20.0 mg L−1 for DCF and 1.00–100 mg L−1 for MF, while the limits of detection were 0.05 and 0.18 mg L−1, respectively.
Received March 27, 2000. Revision November 15, 2000. 相似文献
12.
LI Li jun ** 《高等学校化学研究》2001,17(1):41-47
IntroductionOxalateinnormalurineismainlyformedbythemetaboliteofextrinsicfoodandintrinsicglucoseandprotein .Thehighoxalicacidconcentrationinurineisthemostdangerousfactorresultinginkidneystoneandurinetractstone[1] .Theyareformedprimarilybecauseoftheer roro… 相似文献
13.
Ali Z. Abu Zuhri Nidal A. Zatar Raqi M. Shubietah Hala H. Arafat 《Mikrochimica acta》2000,134(3-4):153-160
Two methods are described for quantitative determination of nizatidine. The first is a cathodic stripping voltammetric method
which is based on the accumulation of the compound at the hanging mercury drop electrode. The adsorptive stripping response
was evaluated with respect of accumulation time, potential, concentration, pH and other variables. A linear calibration graph
was obtained over the range 3.0×10−8–1.0×10−6 M with a detection limit 3.0×10−8 M after a 20s accumulation time at −0.2 V accumulation potential. On the other hand, it was found that the detection limit
could be lowered to 1.0×10−8 M after 180s accumulation time at −0.2 V accumulation potential. The relative standard deviation was in the range 1.2−2.0%
for six measurements. The tolerance amounts of the common excipients have also been reported.
The second is a spectrophotometric method which is based on the formation and extraction of the ion-pair complex formed between
nizatidine and either bromocresol green or bromothymol blue. The extracted colored ion-pair complexes absorb at 416 nm. The
effect of different factors such as: type of organic solvent, pH, reagent concentration, number of extraction times, shaking
time, temperature and the tolerance amount of the common excipients have been reported. The calibration graph was linear in
the range 6.0×10−7–1.8×10−5 M with a detection limit of 6.0×10−7 M and molar absorptivity of 2.1×104 lċmol−1ċcm−1 when using bromocresol green, while the calibration graph was linear in the range 3.0×10−7–1.1×10−5 M with a detection limit of 3.0×10−7 M and molar absorptivity of 3.2×104 lċmol−1ċcm−1 when using bromothymol blue. The spectrophotometric methods offer alternative methods with reasonable sensitivity, selectivity
and accuracy with relative standard deviation in the range 2.1−6.0% and 1.2−4.7% (for six measurements) when using bromothymol
blue and bromocresol green, respectively. The proposed two methods were applied for the determination of nizatidine in commercially
available dosage forms. A comparison between the voltammetric and the extraction-spectrophotometric methods was also reported.
Received April 19, 1999. Revision August 30, 1999. 相似文献
14.
15.
氯酸钾-灿烂甲酚蓝催化褪色光度法测定痕量亚硝酸根的研究 总被引:1,自引:2,他引:1
在0.1 mol/L硫酸介质中,亚硝酸根对KClO3氧化灿烂甲酚蓝的褪色反应具有明显的催化作用,据此建立了催化光度分析测定痕量亚硝酸根的新方法.研究了反应的适宜条件及动力学参数.在最大吸收波长630 nm及选择的最佳实验条件下,方法线性范围为0.05~0.4μg/mL,检出限为0.014μg/mL.该法直接用于雨水和湖水中痕量亚硝酸根的测定,结果满意. 相似文献
16.
阻抑聚丙烯酰胺催化蛋白质-亚甲基蓝褪色光度法测定痕量铋 总被引:3,自引:0,他引:3
在加热条件下,基于Bi(Ⅲ)对聚丙烯酰胺(PAM)催化蛋白-亚甲基蓝(MB)褪色反应有强的抑制作用,建立了动力学光度法测定铋的新方法。△A与CBi(Ⅲ)呈线性关系的范围为0.08-0.48μg/L;检出限为0.004μg/L;对0.04和0.040μgBi(Ⅲ)/L测定的RSD分别为6.4%一2.6%,本阻抑-催化褪色反应对Bi(Ⅲ)、蛋白质-亚甲基蓝和PAM为一级反应,表观活化能为49.22kJ/mol.该方法已用于某些谷物,人发和水样中Bi(Ⅲ)的测定。结果满意。 相似文献
17.
18.
19.
《Analytical letters》2012,45(4):805-815
Abstract This paper describes a kinetic spectrophotometric method for the determination of L‐ascorbic acid (AA) and thiols (RSH). Absorbance of Fe(II)‐phen complex formed during the reaction of AA or RSH with Fe(III)‐phen was continuously measured at 510 nm by double‐beam spectrophotometer with flow cell. For determination some thiols, the catalytic effect of Cu2+ ions was used. AA and RSH can be determined in concentration ranges from 4.0×10?6 to 4.0×10?5 M and from 8.0×10?6 to 8.0×10?5 M, respectively. The applicability of the proposed method was demonstrated by determination of chosen compounds in pharmaceutical dosage forms. 相似文献