共查询到20条相似文献,搜索用时 15 毫秒
1.
Joanna Lenik Cecylia Wardak Barbara Marczewska 《Central European Journal of Chemistry》2008,6(4):513-519
Naproxen membrane electrodes based on different plasticizers and the quaternary ammonium salts (QASs) dimethyldidecylammonium
bromide, methyltrioctylammonium chloride, or tetraoctylammonium chloride, were prepared. The following basic parameters were
investigated for the optimal electrode: measurement range (10−4 − 10−1 mol L−1), slope of the linear range of the calibration curve (−58.3 mV decade−1), limit of detection (6.0 × 10−5 mol L−1), lifetime (2.5 months), dependence of the electrode potential on pH (5.5 − 9.0), reproducibility of potential (1.2 mV) and
selectivity coefficients in relation to selected organic and inorganic anions. The electrode was utilized for determination
of naproxen in tablets by the calibration curve method and the standard addition method.
相似文献
2.
Issac A. Ololade Labunmi Lajide Isiaka A. Amoo 《Central European Journal of Chemistry》2009,7(1):83-89
Seasonal changes in petroleum hydrocarbons in water and streambed sediment from selected oil-related areas of Ondo State,
Nigeria have been examined using gravimetric and infrared methods. The highest and lowest total petroleum hydrocarbon concentrations
(TPH) in water (sediments in brackets) gravimetrically were 3.49 mg L−1 (199.3) mg kg−1 and 0.003 mg L−1 (81.0) mg kg−1 while the concentrations found by IR were 24.0 mg L−1 (135.0 mg kg−1) and 14.0 mg L−1 (33.0 mg kg−1) respectively. The two seasons were positively correlated (α = 0.01) by both methods. The TPH level was well correlated with
the sediment organic carbon (OC) during both seasons. The characteristic carbonyl (C=O) vibrations at 1650 cm−1 and 1700 cm−1 indicate oxidation of the oil residue. The study recommends further investigation into the type of organics present to evaluate
their toxicity and appropriate remediation.
相似文献
3.
Panayot K. Petrov Jožica Majda Serafimovska Sonja Arpadjan Dimiter L. Tsalev Trajče Stafilov 《Central European Journal of Chemistry》2008,6(2):216-221
The influence of EDTA, carboxylic acids, amino-and hydroxocarboxylic acids, monosaccharides and humic substances on the generation
of arsines in hydride generation atomic absorption spectrometry (HGAAS) was investigated. EDTA (0.02 mol L−1), ascorbic acid (0.02 mol L−1) and glucose or fructose (0.2 mol L−1) are useful additives for levelling sensitivities for As(III), monomethylarsonate (MMA) and dimethylarsinate (DMA). The presence
of glycine, malonic, tartaric acids, BICIN and soil humin extracts leads to differences in analytical signal response between
these arsenic species. An analytical application to the determination of the sum of As(III), monomethylarsonate (MMA) and
dimethylarsinate (DMA) as well as the sum of toxicologically relevant hydride forming arsenic fraction As(III) + As(V) + MMA
+ DMA in EDTA soil/sediment extracts using continuous flow HGAAS was demonstrated. The limit of detection was 0.2 mg kg−1 As. Within-day and between-day precision were in the range 3–7% and 4–10%, respectively, for arsenic contents of 0.7–25 mg
kg−1, with recoveries 95–103%.
相似文献
4.
Dispersive liquid-liquid microextraction and liquid chromatographic determination of pentachlorophenol in water 总被引:1,自引:0,他引:1
Khalil Farhadi Mir A. Farajzadeh Amir A. Matin Paria Hashemi 《Central European Journal of Chemistry》2009,7(3):369-374
A simple and sensitive dispersive liquid-liquid microextraction method for extraction and preconcentration of pentachlorophenol
(PCP) in water samples is presented. After adjusting the sample pH to 3, extraction was performed in the presence of 1% W/V
sodium chloride by injecting 1 mL acetone as disperser solvent containing 15 μL tetrachloroethylene as extraction solvent.
The proposed DLLME method was followed by HPLC-DAD for determination of PCP. It has good linearity (0.994) with wide linear
dynamic range (0.1–1000 μg L−1) and low detection limit (0.03 μg L−1), which makes it suitable for determination of PCP in water samples.
相似文献
5.
Aleksandra Prichodko Kristina Jonusaite Vida Vickackaite 《Central European Journal of Chemistry》2009,7(3):285-290
A hollow fibre liquid phase microextraction for gas chromatographic determination of some p-hydroxybenzoic acid esters has
been developed. Chlorobenzene containing tetradecane as internal standard was used for the extraction. Optimized extraction
was carried out at room temperature for 40 min in the presence of 0.4 g mL−1 NaCl in the sample solution. Calibration was linear up to 30 mg L−1. Correlation coefficients were 0.996–0.998. Enrichment factors were 21, 95 and 154, and detection limits were 0.20, 0.03
and 0.01 μg mL−1 for methylparaben, ethylparaben and propylparaben, respectively. Reproducibility was acceptable with relative standard deviations
up to 11.7%. The technique was tested for water and urine analysis.
相似文献
6.
Mónica Díaz-Pérez Manuel Aboal-Somoza Pilar Bermejo-Barrera Adela Bermejo-Barrera 《Central European Journal of Chemistry》2008,6(4):520-525
Preliminary results of development of a direct and fast method of determination of antimony in samples of tap water using
GFAAS are presented. The found levels of antimony were lower than permitted for human consumption. A mixture of Pd and Mg(NO3)2 (concentrations in the injected solution: 8.6 μg mL−1 and 5.8 μg mL−1 respectively) was used as the chemical modifier. The pyrolysis and atomization temperatures were 1000 and 1700°C, respectively
and the mean analytical recovery 98.2%.
相似文献
7.
Aleksandra Dubiella-Jackowska Żaneta Polkowska Lech Dariusz Piotr Pasławski Wojciech Staszek Jacek Namieśnik 《Central European Journal of Chemistry》2009,7(1):35-41
A solid phase extraction technique for the determination of platinum(IV) at trace levels by inductively coupled plasma mass
spectromA solid phase extraction technique for the determination of platinum(IV) at trace levels by inductively coupled plasma
mass spectrometry (ICP-MS) was developed. The method was based on retention of platinum in a sample on silica gel modified
with aminepropyl groups. The retention of platinum(IV) from the sample solution and the recovery of platinum with 1.0 mol
L−1 thiourea solution were quantitative. The relative standard deviation (RSD) was calculated as 5% (n = 7) at the 10 ng L−1 level. The enrichment factor was found to be (50-fold) for 250 mL of water sample. Under optimum conditions, the method detection
limit (MDL) was found to be 1 ng L−1 for platinum in water matrices. Recoveries of Pt from spike addition to atmospheric water samples were quantitative (80–95%).
The present method was used for the determination of platinum in precipitation, throughfall and runoff water samples.
相似文献
8.
Cecylia Wardak 《Central European Journal of Chemistry》2008,6(4):607-612
A new all plastic sensor for Co2+ ions based on 2-amino-5 (hydroxynaphtyloazo-1′)-1,3,4 thiadiazole (ATIDAN) as ionophore was prepared. The electrode exhibits
a low detection limit of 1.5 × 10−6 mol L−1 and almost theoretical Nernstian slope in the activity range 4.0 × 10−6–1 × 10−1 mol L−1 of cobalt ions. The response time of the sensor is less than 10 s and it can be used over a period of 6 months without any
measurable divergence in potential. The proposed sensor shows a fairly good selectivity for Co(II) over other metal ions.
The electrode was successfully applied for determination of Co2+ in real samples and as an indicator electrode in potentiometric titration of Co2+ ions with EDTA.
相似文献
9.
Jaromíra Chýlková Renáta Šelešovská-Fadrná Jaroslava Machalíková 《Central European Journal of Chemistry》2007,5(2):479-495
The optimal process of pre-treatment and activation of gold rotating disc electrode (AuRDE) before voltammetric determination
of mercury is proposed. This treatment encompasses polishing of the electrode surface, electrochemical cycling, and activation.
This procedure both increases determination sensitivity as well as improves determination reproducibility. The detection limit
on the working electrode achieved using this approach amounted to 8.26·10−10 mol L−1for direct mercury determination in water solution (applying 200 s running accumulation). The procedure of the quantitative
mercury isolation from complicated sample matrix was developed as well. It provides better selectivity and significant increase
of sensitivity of mercury determination. In case of mercury isolation from one liter of water the detection limit is 6.23·10−11 mol L−1 (analyzing a greater sample volume the determined concentration could be lower).
相似文献
10.
Hana Dejmkova Candan Dag Jiri Barek Jiri Zima 《Central European Journal of Chemistry》2012,10(4):1310-1317
New methods for the determination of metoclopramide, antiemetic and gastroprokinetic pharmaceutical, were developed, using
differential pulse voltammetry (DPV) and flow injection analysis (FIA) with amperometric detection on a boron-doped diamond
film electrode. Electrode pretreatment necessary to ensure the stable results was investigated and it was found, that while
DPV requires frequent electrode cleaning, FIA with a sufficiently high flow rate can maintain a stable signal with no signs
of electrode passivation. The calculated quantification limits of the DPV and FIA with amperometric detection were 0.13 μmol
L−1 and 0.015 mmol L−1, respectively. The applicability of the new methods was verified by the determination of metoclopramide in a pharmaceutical
preparation. FIA with amperometic detection proved to be sensitive, accurate and, due to the resistance of the electrode to
the passivation, also simple to handle.
相似文献
11.
In the present paper, an off-line preconcentration procedure for the determination of cadmium and lead by flame atomic absorption
spectrometry (FAAS) is proposed. Polyurethane foam (PUF) functionalized with o-aminophenol (o-AP) followed by Pyrazolone (Pyr)
packed in a minicolumn was used as a sorbent material. The metals were retained on the modified PUF, from which it could be
eluted and effectively preconcentrated. The detection limits were 0.072 and 0.016 μg L−1 for Pb and Cd respectively. Enrichment factors were 250 and 319 for lead and cadmium respectively. The procedure has been
applied successfully to metal determination in water samples, fish liver and reference material.
相似文献
12.
Leandro Rodrigues de Lemos Luis Henrique Mendes da Silva Maria do Carmo Hespanhol da Silva Jorge AmimJr Jane Sélia dos Reis Coimbra Luis Antonio Minim 《Central European Journal of Chemistry》2010,8(2):258-263
This work proposes a method for determination Cu(II) concentrations, based on the formation of a copper-1-nitroso-2-naphthol
complex, in the presence of micelles; formed by a triblock copolymer, made up of two blocks of polyethylene oxide (PEO), and
one block of polypropylene oxide (PPO). The insoluble copper complexes, are concentrated inside the hydrophobic micelle core;
formed by the PPO block. For a solution containing 0.200 mg L−1 Cu(II), the proposed method had a relative standard deviation of 2.0% (n = 3); an absolute error from 0.11 to 0.39 mg L−1; and a linear calibration range, from 0.200 to 0.800 mg L−1. Detection and quantification limits, were 43.1 mg L−1 and 144 mg L−1, respectively. We show that there is excellent agreement, between the results obtained using our novel method; and those
obtained using flame atomic absorption spectrometry: In the determination of Cu(II) concentrations, in Brazilian sugar-cane
spirits. The proposed method, is the first to apply macromolecular micelle systems, to the determination of copper concentrations;
and improves upon the results obtained using molecular surfactants. This method is environmentally friendly (since it does
not use any organic solvents for extraction), and the triblock copolymer is biodegradable and non-toxic.
相似文献
13.
Ibuprofen membrane electrodes based on different plasticizers: diisobutyl phthalate (DIBP), o-nitrophenyloctyl ether (o-NPOE),
dioctyl sebacate (DOS) and tetraoctylammonium 2-(4-isobutylphenyl)propionate were prepared. All electrodes show: a near Nernstian
slope of characteristic (58.3–60.9 mV decade−1) in the measurement range (10−4–10−1 mol L−1), limit of detection (5.0×10−5 mol L−1), really long lifetime (12 months), dependence of the electrode potential on pH (5.5–9.0), reproducibility of potential (0.6–1.2
mV) and selectivity coefficients in relation to some organic and inorganic anions. The electrodes were applied for the determination
of ibuprofen in tablets by the calibration curve method and the standard addition method.
相似文献
14.
Jinzhang Gao Yingying Zhang Jie Ren Ming Li Wu Yang 《Central European Journal of Chemistry》2010,8(3):602-606
A sensitive and convenient method for the determination of trace europium ions using an oscillating chemical reaction involving
Ce(IV) - KBrO3 - acetone - oxalic acid - H2SO4 was proposed. The results indicated that the changes in oscillating period (T) was linearly proportional to the negative
logarithmic concentration of Eu3+ (-log C) in the range of 1.41 × 10−8 ˜ 1.41 × 10−4 mol L−1 (r = 0.9982) with a detection limit of 1.04 × 10−9 mol L−1. The recoveries were limited to the range of 99.5% to 100.8%. Under the same conditions, other rare earth ions did not interfere
with the determination of Eu3+. In addition, a perturbation mechanism was also discussed briefly.
相似文献
15.
Paraskevas D. Tzanavaras Theano D. Karakosta Pantelis G. Rigas Demetrius G. Themelis Anastasia Zotou 《Central European Journal of Chemistry》2012,10(5):1459-1463
The first HPLC method for the separation of three paraben preservatives (methyl-, ethyl- and propyl parabens) using a core-shell analytical column is reported in this study. The separation was completed in less than 8 min at a low flow rate of 0.4 mL min−1 and an isocratic mobile phase containing 20% acetonitrile as organic modifier. The backpressure was < 200 bar in all cases, enabling the usage of conventional HPLC equipment. The proposed analytical procedure was validated for linearity (0.5–20 μg L−1), limits of detection (15–43 μg L−1) and quantification (50–142 μg L−1), selectivity, within day (1.3–1.5%) and day-to-day (3.4–4.6%) precision and accuracy. The proposed method has been applied to the determination of the selected paraben preservatives in commercially available hygiene wipes. The mean percent recoveries were found to be in the range of 98.0–98.4%. 相似文献
16.
Ardeshir Shokrollahi Mojtaba Shamsipur Fahimeh Jalali Hamid Nomani 《Central European Journal of Chemistry》2009,7(4):938-944
A simple, sensitive and selective flotation method is described for the preconcentration and atomic absorption spectrometric
determination of zinc ion in water and blood samples. At a solution pH of 5.2, 4-(2-pyridylazo-resorcinol) and Triton X-114
were used as hydrophobic ligand and non-ionic surfactant, respectively. The chemical variables affecting the preconcentration
process were optimized. Under the optimized experimental conditions, the selective preconcentration and determination of as
low zinc concentration as 6.5 μg L−1 can be made. The proposed method was successfully applied to the preconcentration and low-level determination of zinc in
different water and blood serum samples.
相似文献
17.
Jinzhang Gao Haifeng Fan Wu Yang Xiangli Sun Chongyang Li Xuefeng Mao Jie Wang Rong Wang Zhengping Jia 《Central European Journal of Chemistry》2008,6(4):617-621
A rapid, simple and reliable capillary electrophoresis method for the separation and quantitation of inorganic cations with
indirect UV detection at 214 nm was developed. The electrolyte was: 12 mM imidazole as background absorbance provider; 5 mM
malic acid and 1.0 mM 18-crown-6 ether as complexing agents; and 20% D2O (v/v) to improve ion mobility. The pH was 4.25. The applied voltage was 22 kV at 22°C. Nine ions were completely separated
and determined with correlation coefficients of 0.9979-0.9992. The relative standard deviations (RSD) were less than 0.5%
for migration time and less than 5.2% for peak area (n=8). The detection limits (S/N=3) were from 0.08 mg L−1 (for Na+) to 0.51 mg L−1 (for Cu2+). To assess the reliability atomic absorption (AA) was also used to determine the same samples. Satisfactory results were
obtained for real samples of jasmine tea drink and coconut milk.
相似文献
18.
Zholt Kormosh Iryna Hunka Yaroslav Bazel Andriy Laganovsky Iryna Mazurenko Nataliya Kormosh 《Central European Journal of Chemistry》2007,5(3):813-823
The potentiometric response characteristics of a diclofenac selective electrode, based on ion association in different plasticizers,
were compared. The sensitivity, working range, detection limit and selectivity of membrane sensors demonstrated significant
dependence on the type of plasticizers. The potentiometric unit presented a linear response toward diclofenac concentrations
between 1 × 10−5 − 5 × 10−2 mol L−1, with slopes of approximately 60 mV dec−1, and exhibited a response time of 3 s. The potentiometric analysis of sodium diclofenac in pharmaceutical formulations was
perfomed by the membrane electrode proposed and compared with the results of potentiometric titration given by the Pharmacopoeia
of Ukraine.
相似文献
19.
Dmitriy A. Golovko Virender K. Sharma Olga. V. Pavlova Elena. A. Belyanovskaya Igor. D. Golovko Victoria. I. Suprunovich Radek Zboril 《Central European Journal of Chemistry》2011,9(5):808-812
A new amperometric titration method was developed for quantitative determination of ferrate(VI) (FeVIO4
2−) in the 7.06×10−5−5.73×10−3 M concentration range. Chromium(III) hydroxide solution was used as the titrant. The diffusion current (Id) had a linear
relationship with the concentration of ferrate(VI) and slopes were dependent on the concentration of NaOH. The amperometric
titration could detect a lower concentration of ferrate(VI) than could potentiometric and colorimetric titrations. The method
was applied successfully to determine concentrations of ferrate(VI), generated electrochemically, in strong alkaline solutions.
相似文献
20.
Subsurface pollution by volatile organic compounds has emerged as a widespread problem in industrialized countries. This study
compares static headspace technique and methanol extraction/purge-and-trap analysis followed by thermal desorption/gas chromatography
in attempts for quantification of gas survey results in the determination of these chemicals in soil. Several soils were contaminated
with aqueous solution of perchloroethylene (PCE) (140 mg L−1) using a vapor treatment method. Soil spiking took place up to 24 h in desiccator by exposing individual soil samples contained
in open 40 mL glass vials to PCE evaporated from the solution. After exposure the samples were stored and analyzed within
2 days. The achieved results strongly suggest that gas extraction can provide quantitative results, regarding PCE concentration
in soils, which are not significantly different from liquid based extraction analysis.
相似文献