共查询到20条相似文献,搜索用时 31 毫秒
1.
M. E. Abd El-Ghaffar D. R. El-Wasseef D. T. El-Sherbiny S. M. El-Ashry 《Journal of Analytical Chemistry》2011,66(5):476-481
A sensitive, simple and rapid spectrofluorimetric method has been developed for the determination of both Fenoterol hydrobromide
(FNT) and Ritodrine hydrochloride (RTH) in pure and dosage forms. The method is based on derivatization using dansyl chloride (DNS-Cl) as fluorogenic agent and
measuring the fluorescence of the products at emission wavelengths of 517 and 515 nm after excitation at 348 and 343 nm for
FNT and RTH, respectively. Different experimental parameters affecting the fluorescence intensities were carefully studied
and optimized. The relation between fluorescence intensities and drug concentrations were rectilinear over the concentration
range of 0.25–6.0 μg/mL for both drugs with a minimum detectability of 0.065 and 0.045 μg/mL for FNT and RTH, respectively.
The percentage recoveries ±SD were 100.1 ± 0.9, 99.9 ± 0.6 for FNT and RTH respectively. The proposed method was successfully
applied to the determination of both drugs in their commercial dosage forms. The obtained results were statistically validated
and agreed well with those obtained with reference methods. A suggestion for the reaction pathway with DNS-Cl was postulated. 相似文献
2.
A simple, sensitive and selective kinetic spectrofluorimetric determination of NO2 sampled by the droplet method in the atmosphere was proposed on the basis of the reaction of safranin O with nitrite. By
this reaction, a diazonium salt is formed, which causes a fluorescent reddish-orange dye color of the solution to change into
a non fluorescent blue color. The reaction was monitored fluorimetrically by measuring the decrease in fluorescence intensity
of safranin O at (λex/λem = 536 nm/579 nm) by a fixed-time method. The experimental conditions were optimized. Under the optimum conditions in the
concentration range of 7.5–400 ng/ml, a linear calibration curve (r2 = 0.9978) was obtained with a detection limit of 7.5 ng/ml. The method was applied successful ly to the determination of
nitrite in spiked water and NO2 in the atmosphere, as sampled by a liquid droplet method.
Received August 23, 1999. Revision February 29, 2000. 相似文献
3.
Govindaraj Shanmugam Babu Rajendran Ramaswamy Vijayalakshimi Radhakrishnan Hiroaki Tao 《Microchemical Journal》2010,96(2):391-396
The general presumption that the preservative laden personal care products may be one of the causative agents for breast cancer, has remained a matter of controversy during this decade. Extensive studies have not been carried out to either prove or disprove the role of preservatives in breast cancer incidences. In this study we have developed a new method for the identification and quantification of the preservatives such as methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP) and butyl paraben (BuP) in breast tissue using Gas Chromatography and Mass Spectrometry (GC–MS). Tissue was extracted by using acetone:n-hexane mixture (1:1 v/v) and derivatized with N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA). The extent of reaction time and the amount of MSTFA to attain greater derivatization were optimized. The developed method yielded good recovery (mean ± SD) of 99.8 ± 5.1, 96 ± 4.4, 107 ± 17 and 113 ± 13% with relative standard deviations (RSDs) of 5.1, 4.6, 15.6 and 13%, and the limits of detection (LOD) of 2.02, 1.05, 1.71 and 3.75 ng g− 1 for MeP, EtP, PrP and BuP, respectively. The method was successfully validated for the determination of parabens including butyl paraben (log Kow = 3.57) in cancerous breast tissues; this could be a promising one for screening of breast tissues and also the environment for paraben residues. As far as our knowledge goes this is the first GC–MS method for the determination of parabens in human tissue. 相似文献
4.
Pilar Viñas Carmen López-Erroz Francisco Joseé Cerdán Natalia Campillo Manuel Hernández-Córdoba 《Mikrochimica acta》2000,134(1-2):83-87
A new fluorimetric procedure for the determination of thiamine using flow injection analysis is proposed. The method is based
on the derivatization reaction of the primary amine group with o-phthalaldehyde in the presence of 2-mercaptoethanol using fluorimetric detection. The calibration graph based on peak area
was linear in the range 0.2–6 ng mL−1. The detection limit was close to 0.1 ng mL−1. The method was applied to the determination of the vitamin in commercial pharmaceutical preparations.
Received March 31, 1999. Revision October 15, 1999. 相似文献
5.
Ramandeep Kaur Ripneel Kaur Aman Grover Susheela Rani Ashok Kumar Malik Abuzar Kabir Kenneth G. Furton 《Journal of separation science》2019,42(14):2407-2417
A rapid extraction and cleanup method using selective fabric phase sorptive extraction combined with gas chromatography and mass spectrometry has been developed and validated for the determination of broad polarity spectrum emerging pollutants, ethyl paraben, butyl paraben, diethyl phthalate, dibutyl phthalate, lidocaine, prilocaine, triclosan, and bisphenol A in various aqueous samples. Some important parameters of fabric phase sorptive extraction such as extraction time, matrix pH, stirring speed, type and volume of desorption solvent were investigated and optimized. Calibration curves were obtained in the concentration range 0.05–500 ng/mL. Under the optimum conditions, the limits of detection were in the range 0.009 –0.021 ng/mL. This method was validated by analyzing the compounds in spiked aqueous samples at different levels with recoveries of 93 to 99% and relative standard deviations of <6%. The developed method was applied for the determination of the emerging contaminants in tap water, municipal water, ground water, sewage water, and sludge water samples. The results demonstrate that fabric phase sorptive extraction has great potential in the preconcentration of trace analytes in complex matrix. 相似文献
6.
Fermin Capitàn Ramiro Avidad Alberto Navalón Luis F. Capitán-Vallvey 《Mikrochimica acta》1992,107(1-2):65-72
A spectrofluorimetric method for the determination of aluminium at ng/ml level has been developed. The method is based on the formation of a fluorescent 11 complex between Al(III) and 2,6-bis[(o-hydroxy)phenyliminomethyl]-1-hydroxybenzene at an apparent pH of 5.0 in an aqueous-ethanol medium (70% v/v ethanol). The influence of reaction variables is discussed. The range of concentration of the method is 1.0–10.0 ng/ml aluminium, the relative standard deviation 1.5% and the limit of detection 0.1 ng/ml. The advantages of the proposed method include high sensitivity and selectivity. The method has been applied to the determination of aluminium in natural waters. 相似文献
7.
A novel flow injection chemiluminescence (CL) system for the determinati on of pipemidic acid is described. It is based on
the direct CL reaction of pipemidic acid and Co(III) in acid medium. The unstable Co(III) was on-line electrogenerated by
constant current electrolysis. The CL intensity was linear with pipemidic acid concentration in the range of 0.01∼100 μg/ml,
the determination limit was 3.3×10−9 g/mL. The whole process could be complete d in 1 min with a relative standard deviation of 3.2%. The proposed method is suitable
for automatic and continuous analysis and has been applied successfully to the analysis of pipemidic acid in a pharmaceutical
preparation.
Received November 22, 1999. Revision March 24, 2000. 相似文献
8.
Satoshi Kaneco Kazutoshi Sasaki Kiyohisa Ohta Syn-ichi Itoh Takayuki Mizuno 《Mikrochimica acta》1999,131(3-4):205-210
The determination of cobalt by electrothermal atomic absorption spectrometry with a tungsten tube atomizer has been investigated.
The absolute characteristic mass (the mass of element giving 0.0044 abs.) of cobalt by the atomizer was 5.8 pg and the detection
limit was 0.65 ng/ml (3S/N). The interferences caused by large amounts of interferents like Al, Ca, Cu, Fe, K, Mg, Na, Pb
and Zn were evaluated and most of these elements were found to interfere with the cobalt signal. Ammonium thiocyanate as a
chemical modifier was found to be efficient to eliminate the severest interferences. The accuracies of the recommended method
were found to be almost satisfactory for the determination of cobalt in biological materials, as shown by a comparison with
the reported values of NIST materials at the 0.02–0.4 μg/g level.
Received August 24, 1998. Revision February 9, 1999. 相似文献
9.
Lian-Sheng Ling Zhi-Ke He Gong-Wu Song He-You Han Hua-Shan Zhang Yun-E Zeng 《Mikrochimica acta》2000,134(1-2):57-62
A novel fluorimetric method has been developed for selective determination of DNA with the molecular “Light Switch” complex
of Ru(bipy)2(dppz)2+. The maximum fluorescence intensity was produced in the pH range of 9.3–11.5, with the maximum excitation and emission wavelength
of 471.8 nm and 599.8 nm, respectively. Under the optimum conditions, the fluorescence intensity was in proportion to the
concentration of DNA. The linear range for calf thymus DNA salmon sperm DNA and herring sperm DNA reaches from the limit of
determination to 1.5 μg/mL. The limits of determination for calf thymus DNA salmon sperm DNA and herring sperm DNA are 3.3 ng/mL,
2.8 ng/mL and 4.4 ng/mL, respectively. When the proposed method was used to determine DNA in the presence of some coexisting
substances, a satisfactory result was obtained.
Received December 29, 1998. Revision June 28, 1999. 相似文献
10.
In-cuvette mixing and titration techniques have been used for the kinetic determination of sulfide based on its inhibition
effect on the oxidation of indigo carmine with hexacyanoferrate(III) in the presence of silver. The reaction was monitored
spectrophotometrically by measuring the decrease in absorbance of indigo carmine at 612 nm. Both initial rate and fixed-time
methods were applied to the in-cuvette technique. Using in-cuvette mixing, sulfide up to 1800 ng was determined and detection
limit and relative standard deviation for the determination of 120 ng of sulfide were calculated as 23.0 ng and 1.59%, respectively.
On the basis of the titration technique, the upper limit of determination was 25 μg of sulfide and detection limit and average
relative standard deviation for the determination of 1 μg of sulfide were 0.025 μg and 4.95%, respectively. The effect of
foreign ions on the sulfide determination was studied. The proposed methods were applied to the determination of sulfide in
water.
Received: 10 March 1999 / Revised: 9 June 1999 / Accepted: 12 June 1999 相似文献
11.
Alberto Navalón Rachid El-Khattabi Antonio González-Casado José Luis Vilchez 《Mikrochimica acta》1999,130(4):261-265
The reduction reaction of imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] at a mercury electrode shows two well-defined waves in the range of pH 2.0–11.0. The characteristics of the electrode processes were examined. The analyte captures four electrons in the first step and two in the second to give the hydroxylamine and amine derivatives, respectively. A differential-pulse polarographic method for the determination of imidacloprid based on the first reduction peak of this compound is presented. Britton-Robinson buffer was used as a supporting electrolyte and optimum pH value was found to be pH 8.O. The applicable concentration range was from 10 to 200 ng/ml, with a relative standard deviation of 1.5% (for a level of 80 ng/ml) and a detection limit of 3 ng/ml. The method has been satisfactorily applied to the determination of imidacloprid in commercial formulations. 相似文献
12.
A sensitive method is proposed for the determination of palladium, based on its catalytic effect on the reduction of malachite
green by hypophosphite. The reaction rate is monitored by measuring the current of product of reaction at −0.79 V vs. Ag/AgCl
reference electrode. The linear dynamic range is 30.0–300.0 ng/mL with a limit of detection of 10.0 ng/mL. The interference
effects of many ions were studied. The method was used for the determination of Pd(II) in synthetic samples of dental alloys
with satisfactory results. 相似文献
13.
Summary A reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the sensitive and highly selective
determination of histamine in plasma. This method includes selective extraction of histamine from plasma, pre-column derivatisation
in aqueous phase with o-phthaldialdehyde (OPA) and HPLC analysis. The fluorescence of the histamine-OPA-complex was monitored
at wavelengths of 350nm excitation and 450nm emission, after isocratic eluation with a mixture of 0.2 M NaCl and methanol.
The reproducibility of this method including extraction, derivatisation and detection of histamine was >95% in a range of
0.35–17.6 pmol. The HPLC precision was 99±1% at 4 pmol of histamine. The lower limit of detection was 88fmol. A significantly
increased concentration of plasma histamine was detected in patients (n=46) with various liver diseases (0.3–5.2 ng/ml). In
comparison the plasma histamine levels of healthy blood donors were in the range of 0.0–0.4 ng/ml (p<0.01). 相似文献
14.
Stella T. Giroussi Anastasios N. Voulgaropoulos Aristomenis Ayiannidis 《Analytical and bioanalytical chemistry》1997,357(4):429-432
A selective, sensitive and reliable voltammetric method for the simultaneous determination of Cu and Mo is developed. Both
metals form complexes with 8-hydroxyquinoline (oxine). Mo gives two reduction peaks with oxine in acidic chloride media at
−0.52 V and −0.58 V, while copper exhibits only one at −0.14 V. Common heavy metals do not interfere at all. The limit of
detection is 0.29 ng/ml for Mo and 0.14 ng/ml for Cu after preconcentration on the hanging mercury drop electrode for 30 s
at −0.2 V. The R.S.D. at a concentration level of 10 ng/ml is 3.8% for Cu and 5.3% for Mo. The method is applied to different
biological samples.
Received: 15 January 1996/Revised: 11 April 1996/Accepted: 16 April 1996 相似文献
15.
K Li 《Journal of chromatography. A》1992,579(2):209-213
A simple, rapid and highly sensitive reversed-phase liquid chromatographic method has been developed for the determination of sialic acids in human serum. The sialic acids, released by hydrolysis of serum, are converted in borate buffer with malononitrile to highly fluorescent compounds. The reaction mixture is separated isocratically within 5 min using an octadecyl-bonded silica column and a mobile phase of methanol and ammonium acetate buffer (15:85, v/v; pH 5.5). Measurement of the fluorescence intensity of the reaction mixture at 434 nm with irradiation at 357 nm allowed determination of 30-1000 ng/ml of sialic acids with high reproducibility. The limit of detection was 2 ng/ml. Intra-day and inter-day coefficients of variation for assaying 300 ng/ml N-acetylneuraminic acid (NANA) were 1.5% (n = 9) and 2.6% (n = 7), respectively. The recoveries of NANA were 98.5-101.1% for serum. The method has been used for clinical determinations. 相似文献
16.
A simple and fast kinetic method is based on the oxidation of 4-OH coumarone using KMnO4 and the determination of ultramicroamounts of Au(III) by its catalytic effect on this reaction. The sensitivity of the method
is 25 ng/mL. The relative error ranges between 9.20–3.90% for the concentration interval 5 × 10−8–2 × 10−7 g/mL. The selectivity of the method is very good, and the effect of foreign ions is investigated. The proposed approach has
been applied to the determination of traces of Au(III) in copper ore.
The text was submitted by the authors in English. 相似文献
17.
A new method for the determination of traces of iron was developed based on its catalytic effect on the oxidation reaction
of dibromo-p-sulfonic acid-arsenazo (DBS-arsenazo, DBS-ASA) by potassium bromate in a 5.0 × 10−3 M sulfuric acid medium. The optimum experimental conditions for the determination of iron using iron(III)-dibromo-p-sulfonic acid-arsenazo, (DBS-ASA)-potassium bromate-ascorbic acid system and its kinetic spectrophotometric properties were studied. The absorbance difference
(ΔA) is linearly related with the concentration of iron(III) over the range of 0.20–6.0 ng/mL at the maximum absorption wavelength
of 520 nm and described by the equation: ΔA = 0.133c (ng/mL) — 0.0133 with a regression coefficient of 0.9966. The detection limit of the method is 0.17 ng/mL. The method has
been successfully used in the determination of traces of iron in potato samples. The obtained results agree with those of
atomic absorption spectrometry. 相似文献
18.
V. A. Kudrinskaya S. G. Dmitrienko Yu. A. Zolotov 《Moscow University Chemistry Bulletin》2010,65(4):244-248
(4-Nitrophenyl)diazonium tetrafluoroborate (4-NPD) has been proposed as the reagent for the spectrophotometric determination
of flavonoids. 4-NPD has been demonstrated to undergo diazotization reaction with quercitin, naringenin, chrysin, morin, rutin,
and naringin in an alkaline medium leading to the formation of yellow-orange products. The conditions of the spectrophotometric
reaction have been optimized. A procedure for the spectrophotometric determination of flavonoids with the detection limits
(1.5–3.9) × 10−7 M (0.05–0.16 μg/ml) has been developed. Quercitin has been determined in pharmaceutical preparations. 相似文献
19.
N. Gañán Gutiérrez F. Sánchez Rojas J. M. Cano Pavón 《Fresenius' Journal of Analytical Chemistry》1996,355(1):88-91
A room-temperature flow injection spectrofluorimetric method is presented for the determination of Zn(II), based on the use of salicylaldehyde thiocarbohydrazone in the presence of Triton X-100 and sodium acetate-acetic acid buffer. Various physical and chemical variables affecting the reaction in the flow system were evaluated. The proposed method is very selective. The calibration graph is linear over the range 10–1000 ng/ml, with a detection limit of 5 ng/ml and a relative standard deviation at the 50 ng/ml level of 1.8 %. The method was successfully applied to the determination of Zn(II) in drinking waters and biological samples. 相似文献
20.
In a 0.080 M sulphuric acid medium, trace titanium(IV) catalyzes the discoloring reaction of DBC-arsenazo oxidized by potassium
bromate and the discoloring degree is proportional to the concentration of titanium(IV) in the solution. A new catalytic-kinetic
spectrophotometric method for the determination of trace titanium(IV) was developed based on this principle. At a wavelength
of 516 nm, the linear range of determination of titanium(IV) is 0–2.2 μg/25 mL. The detection limit for the determination
of titanium is 2.04 ng/mL. The present method has been satisfactorily applied to the determination of titanium in fish samples.
The text was submitted by the authors in English. 相似文献