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1.
A flow injection system was developed for on-line sorbent extraction preconcentration and flame atomic absorption spectrometric
determination of cadmium in natural water samples. The non-charged cadmium complex with diethyl-dithiophosphate (DDPA) was
formed on-line in 0.1 mol L−1 HNO3 and retained on the hydrophobic poly-chlorotrifluoroethylene (PCTFE) sorbent material. The adsorbed complex was eluted with
isobutyl methylketone (IBMK) and injected directly into the nebulizer via a flow compensation unit. All major chemical and
flow parameters affecting the complex formation adsorption and elution as well as interference were studied and optimized.
By processing 2.4 mL of sample, the enhancement factor was 39 and the sampling frequency was 50 h−1. For 30 s preconcentration time the detection limit was 0.3 μg L−1 and the relative standard deviation at 5.0 μg L−1 Cd concentration level was 2.9%. The calibration curve was linear in the range 0.8–40.0 μg L−1. The accuracy of the method was estimated by analyzing a certified reference material NIST-CRM 1643d (Trace elements in water).
Good recoveries were obtained for spiked natural-water and waste-water samples.
Correspondence: Aristidis N. Anthemidis, Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University,
GR-Thessaloniki 54124, Greece 相似文献
2.
Natalia García-Otero Carmen Teijeiro-Valiño Jacobo Otero-Romaní Elena Peña-Vázquez Antonio Moreda-Piñeiro Pilar Bermejo-Barrera 《Analytical and bioanalytical chemistry》2009,395(4):1107-1115
Nickel(II) and lead(II) ionic imprinted 8-hydroxyquinoline polymers were synthesized by a precipitation polymerization technique
and were used as selective solid phase extraction supports for the determination of nickel and lead in seawater by flow injection
solid phase extraction on-line inductively coupled plasma-optical emission spectrometry. An optimum loading flow rate of 2.25 mL min−1 for 2 min and an elution flow rate of 2.25 mL min−1 for 1 min gave an enrichment factor of 15 for nickel. However, a low dynamic capacity and/or rate for adsorption and desorption
was found for lead ionic imprinted polymer and a flow rate of 3.00 mL min−1 for 4-min loading and a flow rate of 2.25 mL min−1 for 1-min elution gave a enrichment factor of 5. The limit of detection was 0.33 μg L−1 for nickel and 1.88 μg L−1 for lead, with a precision (n = 11) of 8% (2.37 μg Ni L−1) for nickel and 11% (8.38 μg Pb L−1) for lead. Accuracy was also assessed by analyzing SLEW-3 (estuarine water) and TM-24 (lake water) certified reference materials,
and the values determined were in good agreement with the certified concentrations. 相似文献
3.
Jibrin Sabo Suleiman Bin Hu Xuli Pu Chaozhang Huang Zucheng Jiang 《Mikrochimica acta》2007,159(3-4):379-385
A new method is proposed using a microcolumn (20 mm × 2.0 mm) packed with nanometer-sized zirconia as solid-phase extractor
for the separation/preconcentration of Mn, Cu, Cr, Zn, Ni and Co prior to their determination by inductively coupled plasma
optical emission spectrometer (ICP-OES) in environmental samples. The factors affecting the separation and preconcentration
of analytes such as pH, sample flow rate and volume, eluent concentration and volume were determined, interfering ions were
studied, and the optimal experimental conditions were established. The adsorption capacity of nanometer-sized ZrO2 for Mn, Cu, Cr, Zn, Ni and Co was found to be 1.3, 1.3, 1.7, 2.0, 3.9 and 1.5 mg g−1, respectively. The detection limits of the method were 12, 58, 24, 2, 7 and 36 ng L−1, respectively, with a preconcentration factor of 25. The precision of this method was 1.7% (Mn), 2.9% (Cu), 5.9% (Mn), 3.8%
(Mn), 6.2% (Mn) and 4.3% (Mn) with 9 determinations of 10 ng mL−1 of target analytes, respectively. The method was successfully applied to the determination of trace metals in lake water,
dried fish samples, certified reference materials of human hair and milk, and provided satisfactory results. 相似文献
4.
Design of a field flow system for the on-line spectrophotometric determination of phosphate, nitrite and nitrate in natural water and wastewater 总被引:1,自引:0,他引:1
Ioannis A. Tsoulfanidis George Z. Tsogas Dimosthenis L. Giokas Athanasios G. Vlessidis 《Mikrochimica acta》2008,160(4):461-469
This study describes the design and optimisation of a field flow system for the in-situ collection and on-line determination
of phosphate, nitrate and nitrite by flow injection analysis-spectrophotometry. The method is based on the initial determination
of phosphate as its phosphoantimonylmolybdenum blue complex which is then oxidized on-line by nitrite and the decrease in
absorbance is monitored at 880 nm. Nitrate is determined as the difference between total and initial nitrite content in a
separate flow after reduction to nitrite in a cadmium reductive column. The calibration curves were linear in the range 0–2.00 mg L−1 P-phosphate, 0–10.00 mg L−1 nitrite and 0–7.00 mg L−1 nitrate with correlation coefficients of 0.9979, 0.9993 and 0.9995, respectively. The detection limits, calculated as 3S/N,
were 0.15 mg L−1 for P-phosphate, 0.17 mg L−1 for nitrite and 0.09 mg L−1 for nitrate. The reproducibility was below 3.0% (n = 7). Method validation in the analysis of natural water and wastewater samples revealed that it can efficiently be applied
to the determination of the target analytes, with recoveries in the range of 92–108%.
Correspondence: Athanasios G. Vlessidis, Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina,
Ioannina 45110, Greece 相似文献
5.
The redox characteristics of the drug domperidone at a glassy-carbon electrode (GCE) in aqueous media were critically investigated
by differential-pulse voltammetry (DPV) and cyclic voltammetry (CV). In Britton–Robinson (BR) buffer of pH 2.6–10.3, an irreversible
and diffusion-controlled oxidation wave was developed. The dependence of the CV response of the developed anodic peak on the
sweep rate (ν) and on depolizer concentration was typical of an electrode-coupled chemical reaction mechanism (EC) in which an irreversible
first-order reaction is interposed between the charges. The values of the electron-transfer coefficient (α) involved in the rate-determining step calculated from the linear plots of E
p,a against ln (ν) in the pH range investigated were in the range 0.64 ± 0.05 confirming the irreversible nature of the oxidation peak. In
BR buffer of pH 7.6–8.4, a well defined oxidation wave was developed and the plot of peak current height of the DPV against
domperidone concentration at this peak potential was linear in the range 5.20 × 10−6 to 2.40 × 10−5 mol L−1 with lower limits of detection (LOD) and quantitation (LOQ) of 6.1 × 10−7 and 9.1 × 10−7 mol L−1, respectively. A relative standard deviation of 2.39% (n = 5) was obtained for 8.5 × 10−6 mol L−1 of the drug. These DPV procedures were successfully used for analysis of domperidone in the pure form (98.2 ± 3.1%), dosage
form (98.35 ± 2.9%), and in tap (97.0 ± 3.6%) and wastewater (95.0 ± 2.9%) samples. The method was validated by comparison
with standard titrimetric and HPLC methods. Acceptable error of less than 3.3 % was also achieved.
Figure In aqueous media at pH 7.6- 8.4, the DPV and cyclic voltammetry of the drug domperidone (I) at GCE showed an irreversible
and diffusion controlled oxidation wave. The values of the electron transfer coefficient (α) involved in the rate determining
step were found in the range 0.64± 0.05 confirming the irreversible nature of the peak. The analysis of the drug in pure form
and in wastewater samples was successfully achieved 相似文献
6.
Rodrigues TH Rocha MV de Macedo GR Gonçalves LR 《Applied biochemistry and biotechnology》2011,164(6):929-943
In this work, the potential of microwave-assisted alkali pretreatment in order to improve the rupture of the recalcitrant
structures of the cashew able bagasse (CAB), lignocellulosic by-product in Brazil with no commercial value, is obtained from
cashew apple process to juice production, was studied. First, biomass composition of CAB was determined, and the percentage
of glucan and lignin was 20.54 ± 0.70% and 33.80 ± 1.30%, respectively. CAB content in terms of cellulose, hemicelluloses,
and lignin, 19.21 ± 0.35%, 12.05 ± 0.37%, and 38.11 ± 0.08%, respectively, was also determined. Results showed that, after
enzymatic hydrolysis, alkali concentration exerted influence on glucose formation, after pretreatment with 0.2 and 1.0 mo L−1 of NaOH (372 ± 12 and 355 ± 37 mg gglucan−1) when 2% (w/v) of cashew apple bagasse pretreated by microwave-assisted alkali pretreatment (CAB-M) was used. On the other hand, pretreatment
time (15–30 min) and microwave power (600–900 W) exerted no significant effect on hydrolysis. On enzymatic hydrolysis step,
improvement on solid percentage (16% w/v) and enzyme load (30 FPU gCAB-M−1) increased glucose concentration to 15 g L−1. The fermentation of the hydrolyzate by Saccharomyces cerevesiae resulted in ethanol concentration and productivity of 5.6 g L−1 and 1.41 g L−1 h−1, respectively. 相似文献
7.
N. Negreira I. Rodríguez E. Rubí R. Cela 《Analytical and bioanalytical chemistry》2010,398(2):995-1004
The performance of the dispersive liquid–liquid microextraction (DLLME) technique for the determination of eight UV filters
and a structurally related personal care species, benzyl salicylate (BzS), in environmental water samples is evaluated. After
extraction, analytes were determined by gas chromatography combined with mass spectrometry detection (GC-MS). Parameters potentially
affecting the performance of the sample preparation method (sample pH, ionic strength, type and volume of dispersant and extractant
solvents) were systematically investigated using both multi- and univariant optimization strategies. Under final working conditions,
analytes were extracted from 10 mL water samples by addition of 1 mL of acetone (dispersant) containing 60 μL of chlorobenzene
(extractant), without modifying either the pH or the ionic strength of the sample. Limits of quantification (LOQs) between
2 and 14 ng L−1, inter-day variability (evaluated with relative standard deviations, RSDs) from 9% to 14% and good linearity up to concentrations
of 10,000 ng L−1 were obtained. Moreover, the efficiency of the extraction was scarcely affected by the type of water sample. With the only
exception of 2-ethylhexyl-p-dimethylaminobenzoate (EHPABA), compounds were found in environmental water samples at concentrations between 6 ± 1 ng L−1 and 26 ± 2 ng mL−1. 相似文献
8.
Jorge L. Guzmán Mar Leticia López Martínez Pedro L. López de Alba Jesús E. Castrejón Durán Víctor Cerdà Martín 《Mikrochimica acta》2006,153(3-4):139-144
1-Naphthylamine (NPA) is one of the main degradation products of pesticides derived from naphthalene, and a well-known bladder
carcinogen in men. The Griess assay is used for NPA determination because of its high sensitivity and selectivity. The azo
dye 4-(sulphophenylazo)-1-naphthylamine is formed, which shows a peak maximum at 540 nm. After optimizing multisyringe flow
injection analysis (MSFIA) parameters, the analytical characteristics of the method were obtained, with a working linear range
of 0.5 to 14 mg L−1, according to the equation A = 0.0738±0.0019 [NPA] + 0.0028 ± 0.0042, r = 0.9997. Values for RSD (%) and Erel (%) were calculated for the concentration levels of 0.5, 6 and 12 mg L−1; values obtained were 1.1, 0.4 and 0.3% for RSD and 0.8, 0.3 and 0.2% for Erel, respectively. LD was 0.01 mg L−1 and LQ was 0.04 mg L−1 NPA. The MSFIA procedure for the determination of NPA was applied to different water samples (well water, tap water, seawater,
and wastewater from the EDAR-1, Palma de Mallorca water treatment plant), with satisfactory results and a throughput of 90
samples per hour. 相似文献
9.
A novel flow injection procedure has been developed for the determination of tannic acid based on the inhibition of the chemiluminescences
in luminol-H2O2-Manganese tetrasulfonatophthalocyanine (MnTSPc) system by tannic acid. The method is simple, rapid and sensitive with a detection
limit of 8 × 10−10 mol·L−1 and a linear range of 7 × 10−9–5 × 10−6 mol·L−1. The relative standard deviation is 1.9% for eleven measurements of 5 × 10−7 mol·L−1 tannic acid. The method has been successfully applied to the determination of tannic acid in real Chinese gall and hop pellets
samples. 相似文献
10.
Guzmán-Vázquez de Prada A Loaiza OA Serra B Morales D Martínez-Ruiz P Reviejo AJ Pingarrón JM 《Analytical and bioanalytical chemistry》2007,388(1):227-234
A molecularly imprinted polymer was developed and used for solid-phase extraction (MISPE) of the antihelmintic fenbendazole
in beef liver samples. Detection of the analyte was accomplished using square wave voltammetry (SWV) at a cylindrical carbon
fibre microelectrode (CFME). A mixture of MeOH/HAc (9:1) was employed both as eluent in the MISPE system and as working medium
for electrochemical detection of fenbendazole. The limit of detection was 1.9 × 10−7 mol L−1 (57 μg L−1), which was appropriate for the determination of fenbendazole at the maximum residue level permitted by the European Commission
(500 μg kg−1 in liver). Given that the SW voltammetric analysis could not be directly performed in the sample extract as a consequence
of interference from some sample components, a sample clean-up with a MIP for selectively retaining fenbendazole was performed.
The MIP was synthesized using a 1:8:22 template/methacrylic acid/ethylene glycol dimethacrylate ratio. A Britton–Robinson
Buffer of pH 9.0 was selected for retaining fenbendazole in the MIP cartridges, and an eluent volume of 5.0 mL at a flow rate
of 2.0 mL min−1 was chosen in the elution step. Cross-reactivity with the MIP was observed for other benzimidazoles. The synthesized MIP
exhibited a good selectivity for benzimidazoles with respect to other veterinary drugs. The applicability of the MISPE-SWV
method was tested with beef liver samples, spiked with fenbendazole at 5,000 and 500 μg kg−1. Results obtained for ten different liver samples yielded mean recoveries of (95 ± 12)% and (96 ± 11)% for the upper and
lower concentration level, respectively. 相似文献
11.
This work describes a new analytical procedure for trace vanadium by graphite furnace atomic absorption spectroscopy coupled
to cloud point extraction (CPE) as the separation-preconcentration method. The CPE behavior of vanadium using methylene blue
as complex agent and Triton X-100 as a surfactant was investigated systematically. Under the optimized conditions, the detection
limit was 0.7 ng · mL−1, and the relative standard deviation was 4.3% for vanadium (c = 50.0 ng · mL−1, n = 5). The recovery of vanadium was in the range of 98.9–102.8%. The method was applied to the analysis of vanadium in certified
reference materials and real samples. The results obtained were in good agreement with the certified values.
Correspondence: Xiashi Zhu, Key Laboratory of Environmental Material and Environmental Engineering of Jiangsu province/College
of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, P.R. China 相似文献
12.
The development and characterization of one rat monoclonal antibody (mAb) for 2,4-dinitroaniline and of two rat mAbs for 2,6-dinitroaniline
are described. With the immunization of rats with 2,4,6-trinitrophenyl-glycylglycine–keyhole limpet hemocyanine (KLH) conjugate
one mAb (PK 5H6) has been developed and formatted into a competitive enzyme-linked immunosorbent assay (ELISA). This assay
no. 1 is very sensitive for 2,4-dinitroaniline with a test midpoint of 0.24 ± 0.06 μg L−1 (n = 19) in 40 mM phosphate-buffered saline (PBS). A second hapten, 3-(4-amino-2,6-dinitrophenyl)propionic acid, which was also
conjugated to KLH and used for the immunization of rats, led to two sensitive ELISAs for 2,6-dinitroaniline in 40 mM PBS with
test midpoints of 0.61 ± 0.08 μg L−1 (n = 15; mAb DNT4 3C6; assay no. 2) and 0.94 ± 0.29 μg L−1 (n = 17; mAb DNT4 1A7, assay no. 3). Selectivities of all mAbs were checked with more than 20 compounds, including nitroaromatic
compounds, 2,6-dinitroaniline pesticides, and other substituted derivatives of aniline. As very noticeable cross-reactivities,
all mAbs recognize 2-chloro-4,6-dinitroaniline, 4-chloro-2,6-dinitroaniline and 2-bromo-4,6-dinitroaniline, the last of these
being a major metabolite of the azo dye Disperse Blue 79. As first demonstrations of applications, two ELISAs (assays no.
1 and 2) were used for the analysis of 2,4- or 2,6-dinitroaniline in spiked water and soil samples. Recovery data were determined
and the majority of these data were in the range of 90–120%. These assays can contribute to a very cost-effective and environmentally
friendly immunochemical surveillance monitoring of environmental samples for contaminations with these compounds. To the best
of the authors’ knowledge, these are the first antibodies described for 2,4-dinitroaniline and for 2,6-dinitroaniline. 相似文献
13.
Krska R Schubert-Ullrich P Josephs RD Emteborg H Buttinger G Pettersson H van Egmond HP Schothorst RC Macdonald S Chan D 《Analytical and bioanalytical chemistry》2007,388(5-6):1215-1226
This paper presents results from the European Commission-funded project Doncalibrant, the objective of which was to produce
calibrators with certified mass fractions of the Fusarium toxins deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-Ac-DON), 15-acetyldeoxynivalenol (15-Ac-DON), and nivalenol (NIV),
in acetonitrile. The calibrators, available in ampoules, were sufficiently homogeneous, with between-bottle variations (s
bb) of less than 2%. Long-term stability studies performed at four different temperatures between −18 and 40 °C revealed no
significant negative trends (at a confidence level of 95%). Molar absorptivity coefficients (in L mol−1 cm−1) were determined for all four toxins (DON: 6805 ± 126, NIV: 6955 ± 205, 3-Ac-DON: 6983 ± 141, 15-Ac-DON: 6935 ± 142) on the
basis of a mini-interlaboratory exercise. The overall uncertainty of the calibrators’ target values for DON and NIV were evaluated
on the basis of gravimetric preparation data and include uncertainty contributions from possible heterogeneity, storage, and
transport. The Doncalibrant project resulted in the production of calibrators for DON (IRMM-315) and NIV (IRMM-316) in acetonitrile
with certified mass fractions of 25.1 ± 1.2 μg g−1 and 24.0 ± 1.1 μg g−1, respectively. Both CRMs became commercially available from the Institute for Reference Materials and Measurements (IRMM,
Geel, Belgium) at the beginning of 2007. 相似文献
14.
The fabrication and electrochemical characteristics of a penicillamine (PCA) self-assembled monolayer modified gold electrode
were investigated. The electrode can enhance the electrochemical response of uric acid (UA), and the electrochemical reaction
of UA on the PCA electrode has been studied by cyclic voltammetry and differential pulse voltammetry. Some electrochemical
parameters, such as diffusion coefficient, standard rate constant, electron transfer coefficient and proton transfer number
have been determined for the electrochemical behavior on the PCA self-assembled monolayer electrode. The electrode reaction
of UA is an irreversible process, which is controlled by the diffusion of UA with two electrons and two protons transfer at
the PCA/Au electrode. In phosphate buffer (pH 5.0), the peak current is proportional to the concentration of UA in the range
of 6.0 × 10−5–7.0 × 10−4 mol L−1 and 2.0 × 10−5–7.0 × 10−4 mol L−1 for the cyclic voltammetry and differential pulse voltammetry methods with the detection limits of 5.0 × 10−6 and 3.0 × 10−6 mol L−1, respectively. The method can be applied to determine UA concentration in real samples. 相似文献
15.
On the basis of flow injection analysis technology, a simple, accurate, and sensitive method has been developed for the determination
of volatile phenols in environmental water samples by using CdTe/ZnSe nanocrystals as a fluorescent probe. The influences
of coexisting metal ions and volatile phenol substitutes were also investigated. The method developed for analysis of volatile
phenols displayed very good linearity in the range from 1.0 × 10−8 to 4.0 × 10−7 g L−1, with a correlation coefficient greater than 0.995 and a detection limit down to 2.7 × 10−9 g L−1 (signal-to-noise ratio 3). The proposed method was successfully applied to determine the content of volatile phenols in environmental
water samples, and the quantitative recoveries were 93.4–106.1%. A possible reaction mechanism for the quenching of fluorescence
is discussed using UV–vis absorption spectra, fluorescence spectra, and time-resolved luminescence spectra of volatile phenols
obtained by titrating a CdTe/ZnSe nanocrystal aqueous solution and zeta potential data. 相似文献
16.
Absolute protein quantification has become an important challenge in modern bioanalytical chemistry. Among several approaches
based on mass spectrometric techniques, inductively coupled plasma (ICP) as ionisation source provides element-selective and
sensitive detection of heteroatoms, and thus, a potentially emerging tool in protein analysis. In this work we applied coupling
of capillary liquid chromatography (μLC) and inductively coupled plasma-sector field mass spectrometry (ICP–SFMS) to the separation
and determination of standard proteins. For quantification purposes, post-column isotope dilution of sulfur was applied and
optimised for this type of hyphenated technique. Provided that the protein sequence is known (number of sulfur-containing
amino acids, i.e. cysteines and methionines) the protein amount can then be directly calculated from the determined sulfur
content in a certain protein fraction. In order to prove the reliability of the presented method, two different certified
reference materials were analysed: CRM 393 (human apolipoprotein A-I) and CRM 486 (α-fetoprotein). For CRM 393 excellent agreement
(37.0 ± 1.4 μmol L−1) was obtained with the certificate (37.7 ± 1.8 μmol L−1). However, the recovery rate for α-fetoprotein in CRM 486 was found to be about 60% indicating incomplete elution of the
protein during the chromatographic separation. 相似文献
17.
Gema Paniagua González Pilar Fernández Hernando Jesús Senén Durand Alegría 《Analytical and bioanalytical chemistry》2009,394(4):963-970
This work reports a comparative study of two automated flow-through fluorosensors for the determination of digoxin in serum
samples: an immunosensor with an anti-digoxin polyclonal antibody as the reactive phase permanently immobilised on controlled-pore
glass and a sensor with a selective reaction system based on a methacrylic molecularly imprinted polymer (MIP) synthesised
by bulk polymerisation. The variables affecting the sensitivity and dynamic range of the sensors (e.g. the carrier and elution
solutions, flow rates, pH and reagent concentrations) were optimized, and the binding characteristics of their reactive phases
were compared in a competitive fluorescent assay. Digoxin was reproducibly determined by both sensors at the milligram per
litre level (detection limit = 1.20 × 10−3 mg L−1 and RSD = 4–7% for the immunosensor; detection limit = 1.7 × 10−5 mg L−1 and RSD = 1–2% for the MIP sensor). No cross-reactivity with digoxin-related compounds was seen for either sensor at a digoxin/interferent
ratio of 1:100. The lifetime of the immunosensor was about 50 immunoassays; its shelf life, when unused, is about 3 months.
The lifetime of the MIP sensor was over 18 months. Both sensors were used to determine the digoxin concentration of human
serum samples with satisfactory results. 相似文献
18.
Jamshid L. Manzoori Hossein Abdolmohammad-Zadeh Mohammad Amjadi 《Mikrochimica acta》2007,159(1-2):71-78
A simple and sensitive cloud point extraction method has been developed for the preconcentration of ultra-trace amounts of
gold as a prior step to its determination by electrothermal atomic absorption spectrometry. It is based on the extraction
of gold in hydrochloric acid medium using the non-ionic surfactant polyethyleneglycolmono-p-nonylphenylether (PONPE 7.5) without adding a chelating agent. The preconcentration of a 50 mL sample solution was thus enhanced
by a factor of 200. The resulting calibration graph was linear in the range of 10–200 ng L−1 with a correlation coefficient of 0.9993. The limit of detection (3s) obtained under optimal conditions was 2.0 ng L−1. The relative standard deviation for 10 replicate determinations at a 100 ng L−1 Au level was 3.6%. The method was applied to the ultra-trace determination of gold in water and copper samples. 相似文献
19.
In the presence of carbonate and uranine, the chemiluminescent intensity from the reaction of luminol with hydrogen peroxide
was dramatically enhanced in a basic medium. Based on this fact and coupled with the technique of flow-injection analysis,
a highly sensitive method was developed for the determination of carbonate with a wide linear range. The method provided the
determination of carbonate with a wide linear range of 1.0 × 10−10–5.0 × 10−6 mol L−1 and a low detection limit (S/N = 3) of carbonate of 1.2 × 10−11 mol L−1. The average relative standard deviation for 1.0 × 10−9–9.0 × 10−7 mol L−1 of carbonate was 3.7% (n = 11). Combined with the wet oxidation of potassium persulfate, the method was applied to the simultaneous determination
of total inorganic carbon (TIC) and total organic carbon (TOC) in water. The linear ranges for TIC and TOC were 1.2 × 10−6–6.0 × 10−2 mg L−1 and 0.08–30 mg L−1 carbon, respectively. Recoveries of 97.4–106.4% for TIC and 96.0–98.5% for TOC were obtained by adding 5 or 50 mg L−1 of carbon to the water samples. The relative standard deviations (RSDs) were 2.6–4.8% for TIC and 4.6–6.6% for TOC (n = 5). The mechanism of the chemiluminescent reaction was also explored and a reasonable explanation about chemical energy
transfer from luminol to uranine was proposed.
Figure Chemiluminescence profiles in batch system. 1, Injection of 100 μL of K2CO3 into 1.0 mL luminol-1.0 mL H2O2 solution; 2-3 and 4-5, Injection in sequence of 100 μL of K2CO3 and 100 μL of uranine into 1.0 ml luminol-1.0 mL H2O2 solution; Cluminol = 1.0 × 10−7 mol/L, CH2O2 = 1.0 × 10−5 mol/L, Curanine = 1.0 × 10−5 mol/L, CK2CO3 = 1.0 × 10−7 mol/L except for 4-5 where CK2CO3 = 1.0 × 10−4 mol/L 相似文献
20.
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