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1.
A suitable and sensitive ion chromatographic measuring system for determining the main components at nanogram to milligram per liter levels in water samples from the electrodeionization process is presented. A modified Dionex system offers the possibility for the determination of anions and cations in the samples at ng/L, μg/L and mg/L levels. The ng/L level of anions and cations in 20–130 mL high-purity water can be analyzed immediately after preconcentration on appropriate exchange columns. The mg/L level samples are successfully determined by use of an auto-sampler. The quantification of each ion is achieved using the suppressor technique and a conductivity detector. Samples are taken from 5 steps of the electrodeionization process and stored in pre-cleaned FEP (fluorinated ethylene propylene) at 7?°C in darkness prior to the determination of chloride, nitrate, sulfate, carbonate, sodium, ammonium, potassium, calcium and magnesium. Eluents, ultrapure water and samples for the determination of carbonate were passed through special glass containers and flushed with helium gas to avoid the effect of atmospheric carbon dioxide. Results of the investigation of the cationic and anionic composition in water samples within the electrodeionization process are presented and discussed. 相似文献
2.
Van Dy Nguyen 《Fresenius' Journal of Analytical Chemistry》1996,354(5-6):738-741
An ion chromatographic measuring system for the off-line and on-line determination of some trace anions and cations in high-purity water is presented. The ng/L level of anions and cations in 20–130 mL high-purity water can be analyzed after preconcentration on ion exchange columns. The concentrated solutes are eluted by eluents from the trap column and separated using a Dionex analytical column. The quantification of each ion is achieved using the suppressor technique and conductivity detector. The influence of various parameters on the results is discussed. The detection limits of cations and anions are between 10 and 30 ng/L for chloride, bromide, nitrate, phosphate, sulphate, sodium, ammonium, potassium, magnesium and calcium ions. 相似文献
3.
Nguyen VD 《Analytical and bioanalytical chemistry》1996,354(5-6):738-741
An ion chromatographic measuring system for the off-line and on-line determination of some trace anions and cations in high-purity water is presented. The ng/L level of anions and cations in 20-130 mL high-purity water can be analyzed after preconcentration on ion exchange columns. The concentrated solutes are eluted by eluents from the trap column and separated using a Dionex analytical column. The quantification of each ion is achieved using the suppressor technique and conductivity detector. The influence of various parameters on the results is discussed. The detection limits of cations and anions are between 10 and 30 ng/L for chloride, bromide, nitrate, phosphate, sulphate, sodium, ammonium, potassium, magnesium and calcium ions. 相似文献
4.
Chances are examined for the identification and determination of pesticides of different types and polycyclic aromatic hydrocarbons,
46 items, in water and food by means of gas chromatography with time-of-flight mass spectrometry detection. The detection
limits make from 0.01 to 0.5 mg/L if the injected volume of samples is 1 μL; the analytical range is 0.02–10 mg/L. In the
mode of selective ion registration and preliminary preconcentration by liquid and solid-phase extraction, the detection limits
of analytes make from 2 to 100 ng/L in water and from 0.2 to 10 μg/kg for solid samples. 相似文献
5.
An improvement of the peak parking technique is described for the serial determination of cations (Na+, , K+, Mg2+, and Ca2+) and anions (Cl−, , and ) using a single pump, a single eluent and a single detector. The present system used commercially-available unmodified cation
exchange and anion exchange columns, which were attached to each switching valve. When 1.75 mM 5-sulfosalicylic acid was
used as the eluent, serial separation of the above cations and anions was achieved in less than 20 min. The proposed ion chromatographic
method was successfully applied to the serial determination of cations and anions in tap water and river water samples. The
limits of detection at S/N=3 for an injection of 20 μl were 16–68 ppb (μg/l) for cations and 15–28 ppb for anions. 相似文献
6.
José L. F. C. Lima C. Delerue-Matos M. Carmo M. C. V. F. Vaz Jeanine Silva 《Fresenius' Journal of Analytical Chemistry》1999,364(3):266-269
A flow injection analysis (FIA) system with potentiometric detection has been developed for the determination of citric acid
in commercial fruit juices using a copper-selective tubular electrode. It consists of the complexation of citrate ion with
copper (II) ion, monitoring the free copper (II) concentration. Linear relationships between the potential and log concentrations
of citric acid in the range of 1 × 10–3 mol/L – 1 × 10–2 mol/L were attained with samples injected in the system without prior treatment. Repeatability was determined by assessing
the relative standard deviation for ten replicate injections of different juice samples which varied from 1.2% to 3.0%. The
results provided by the automated system were compared with those of an enzymatic conventional method used for the analysis
of citric acid in food and a relative deviation of less than 4.0% was found. Recovery trials resulted in values from 97.0%
to 101.0%. The system allows a sampling frequency of 60 samples/h.
Received: 22 October 1998 / Revised: 14 December 1998 / Accepted: 16 December 1998 相似文献
7.
Resonance Rayleigh scattering for the determination of cationic surfactants with Eosin Y 总被引:15,自引:0,他引:15
Resonance Rayleigh scattering (RRS) of cationic surfactants–Eosin Y systems and their analytical application have been studied.
In aqueous solution at pH 2∼3, Eosin Y reacts with a monomer of cationic surfactants (CS), such as Zephiramine (Zeph), tetradecylpyridinium
bromide (TPB), cetylpyridinium bromide (CPB), cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CTMAB), to
form an ion associate and a new RRS spectrum appears. The spectral characteristics of the five ion associates are similar
and their maximum scattering wavelengths (λmax) are all at 313 nm. The intensity of RRS at λmax of the ion associate is directly proportional to the concentration of CS in the range of 0∼3.0 μg/25 mL. The technique has
high sensitivity for the determination of CS; their detection limit is between 5.57 ng/mL and 7.60 ng/mL depending on the
CS. In this case, most metal and non-metal ions, NH4
+ and some anionic surfactants do not interfere, so that the method has a good selectivity. It can be applied to the determination
of trace amounts of cationic surfactants in water samples.
Received: 9 September 1998 / Revised: 17 November 1998 / Accepted: 18 November 1998 相似文献
8.
Ludovica Verzegnassi Catherine Riffé-Chalard Werner Kloeti F. O. Güla?ar 《Fresenius' Journal of Analytical Chemistry》1999,364(3):249-253
A new application is described of the on-line high-performance liquid chromatography/positive and negative ion atmospheric
pressure chemical ionization mass spectrometry (APCI(+/–)-MS) to the identification of tetrapyrrolic compounds in sediment
samples containing complex mixtures of natural pigments and their diagenetic products. The method relies on the production
of radical anions in order to determine the molecular masses of the molecules which yield abundant fragment ions when analyzed
in the positive mode. This approach allows to verify the occurrence of coeluting components by examining their negative ion
spectra and to complete their identification on the basis of their fragment ions produced in the positive ion spectra.
Received: 24 September 1998 / Revised: 23 December 1998 / Accepted: 29 December 1998 相似文献
9.
Ludovica Verzegnassi Catherine Riffé-Chalard Werner Kloeti F. O. Gülaçar 《Analytical and bioanalytical chemistry》1999,364(3):249-253
A new application is described of the on-line high-performance liquid chromatography/positive and negative ion atmospheric
pressure chemical ionization mass spectrometry (APCI(+/–)-MS) to the identification of tetrapyrrolic compounds in sediment
samples containing complex mixtures of natural pigments and their diagenetic products. The method relies on the production
of radical anions in order to determine the molecular masses of the molecules which yield abundant fragment ions when analyzed
in the positive mode. This approach allows to verify the occurrence of coeluting components by examining their negative ion
spectra and to complete their identification on the basis of their fragment ions produced in the positive ion spectra.
Received: 24 September 1998 / Revised: 23 December 1998 / Accepted: 29 December 1998 相似文献
10.
Martin Seifert Gerald Brenner-Wei? Stefanie Haindl Michael Nusser Ursula Obst B. Hock 《Fresenius' Journal of Analytical Chemistry》1999,363(8):767-770
The wide variety of known and unknown endocrine disruptors demands highly efficient methods for detecting the relevant endocrine
disrupting pollutants. Bioeffects-related analysis is expected to solve this problem, combining biomolecular recognition processes
with chemical analysis, which therefore reduces costs of instrumental chemical analysis to relevant samples. The hyphenation
of both steps provides information on potential bioeffects, structure and concentration of the substances of interest. In
this work the hyphenation of an enzyme-linked receptor assay (ELRA) with liquid chromatography-tandem mass spectrometry (LC-MSMS)
for the analysis of estrogens and xenoestrogens is proposed. Both test systems have been validated with standards and spiked
real water samples. The ELRA achieved a detection limit of 0.1 μg/L for 17β-estradiol (without preconcentration). With the
LC-MSMS method, steroids could be detected down to 1 ng/L (with preconcentration). Two concepts for a tighter hyphenation
of biomolecular interaction and chemical analysis are discussed: the on-line coupling of receptor-affinity chromatography
(RAC) to LC-MSMS and the direct measurement of receptor-ligand complexes by LC-MSMS.
Received: 30 October 1998 / Revised: 18 December 1998 / Accepted: 26 December 1998 相似文献
11.
Martin Seifert Gerald Brenner-Weiß Stefanie Haindl Michael Nusser Ursula Obst B. Hock 《Analytical and bioanalytical chemistry》1999,363(8):767-770
The wide variety of known and unknown endocrine disruptors demands highly efficient methods for detecting the relevant endocrine
disrupting pollutants. Bioeffects-related analysis is expected to solve this problem, combining biomolecular recognition processes
with chemical analysis, which therefore reduces costs of instrumental chemical analysis to relevant samples. The hyphenation
of both steps provides information on potential bioeffects, structure and concentration of the substances of interest. In
this work the hyphenation of an enzyme-linked receptor assay (ELRA) with liquid chromatography-tandem mass spectrometry (LC-MSMS)
for the analysis of estrogens and xenoestrogens is proposed. Both test systems have been validated with standards and spiked
real water samples. The ELRA achieved a detection limit of 0.1 μg/L for 17β-estradiol (without preconcentration). With the
LC-MSMS method, steroids could be detected down to 1 ng/L (with preconcentration). Two concepts for a tighter hyphenation
of biomolecular interaction and chemical analysis are discussed: the on-line coupling of receptor-affinity chromatography
(RAC) to LC-MSMS and the direct measurement of receptor-ligand complexes by LC-MSMS.
Received: 30 October 1998 / Revised: 18 December 1998 / Accepted: 26 December 1998 相似文献
12.
建立了使用高压离子色谱快速测定饮用水中7种无机阴离子的方法。环境水样经0.22 μm尼龙滤膜过滤后可直接进样分析。采用Dionex Integrion高压离子色谱仪和AS22-Fast-4 μm阴离子交换柱(150 mm×4 mm),可在5 min内完成对F-、Cl-、Br-、NO2-、NO3-、SO42-和PO43-这7种阴离子的分析。以4.5 mmol/L碳酸钠和1.4 mmol/L碳酸氢钠为淋洗液,流速为2mL/min。7种阴离子的检出限为0.007~0.07 mg/L(S/N=3),在较宽范围内有良好的线性关系(相关系数不小于0.999)和重现性(相对标准偏差不大于0.48%,n=8)。实际样品加标回收率为91.4%~109.7%,相对标准偏差为0.30%~0.45%(n=5)。将该方法应用于饮用水厂进出水的分析,结果表明在进出水中检出6种阴离子,以Cl-、NO3-和SO42-为主。该方法简便快速、灵敏准确,尤其适合高通量样品中阴离子的快速分析。 相似文献
13.
Determination of carbon dioxide and acid components in exhaust gas by suppressed ion chromatography. 总被引:1,自引:0,他引:1
Makoto Nonomura 《Analytical sciences》2004,20(1):219-222
Although anions are usually determined by suppressed ion chromatography (IC), carbonate and bicarbonate ions can not be determined, because a mixed solution of sodium carbonate and sodium hydrogencarbonate is used as the eluent. This paper describes an IC method for the determination of carbonate ion and common anions using an IonPac AG17/AS17 column, an EG 40 eluent generator and a conductivity detector. The proposed IC method could determine carbonate ion and anions within 6 min. The relative standard deviations (n = 5) for chloride (0.4 mg L(-1)), nitrite (0.8 mg L(-1)), carbonate (100 mg L(-1)), nitrate (1.0 mg L(-1)) and sulfate (2.0 mg L(-1)) ions were 5.1%, 1.1%, 4.2%, 5.1% and 1.1%, respectively. In addition, the absorbing solution of carbon dioxide was examined, and 2-amino-2-methyl-1-propanol was found to be a good absorbing solution. The proposed IC method was applied to the determination of carbon dioxide and acid components in flue gas and automobile exhaust gas. 相似文献
14.
Rahmiana Zein Edison Munaf Toyohide Takeuchi Tomoo Miwa 《Analytical and bioanalytical chemistry》1997,357(4):466-468
Microcolumn ion chromatography of inorganic anions has been studied using octadecylsilica immobilized with bovine serum albumin
as a stationary phase. The analytes were monitored with a conductivity detector. The detection limits for chloride, nitrate
and thiocyanate at S/N = 3 were 0.8, 1.0 and 3.0 μmol L–1, respectively. The present system was applied to the determination of inorganic anions in tap water and serum samples.
Received: 29 May 1996 / Accepted: 12 August 1996 相似文献
15.
An HPLC/fluorescence method is described, which enables the sensitive determination of airborne monomeric 4,4′-diphenyl-methane-diisocyanate
(MDI). A glass fiber filter coated with 1 mg 1-(2-pyridyl)-piperazine (2PP) is used for sampling. The urea derivative MDI-2PP,
which shows a high molecular absorption coefficient and exhibits a sufficient fluorescence response, is extracted from the
filter by use of a 90:10 acetonitrile/DMSO mixture. Linear calibration curves were obtained for the indoor range (7.8 ng/mL
to 74.7 ng/mL) and the workplace range (27.7 ng/mL to 676.0 ng/mL). A detection limit of 9.0 ng/m3 can be achieved on a total sampling volume of 1000 L. The method is easy to handle and therefore highly suitable for a routine
determination of MDI in the atmosphere of workplace areas and living environments.
Received: 17 December 1997 / Revised: 2 March 1998 / Accepted: 4 March 1998 相似文献
16.
A method of reversed‐phase ion‐pair solid‐phase extraction combined with ion chromatography for determination of pyrrolidinium ionic liquid cations (N‐methyl‐N‐ethyl pyrrolidinium, N‐methyl‐N‐propyl pyrrolidinium, and N‐methyl‐N‐butyl pyrrolidinium) in water samples was developed in this study. First, ion‐pair reagent sodium heptanesulfonate was added to the water samples after static, centrifugation and filteration. Then, pyrrolidinium cations in the samples were enriched and purified by a reversed‐phase solid‐phase extraction column, and eluted from the column with methanol aqueous solution as eluent. Finally, the eluate collected was analyzed by ion chromatography. The separation and direct conductivity detection of these pyrrolidinium cations by ion‐exchange column using 1.0 mM methanesulfonic acid (in water)/acetonitrile (97:3, v:v) as mobile phase was achieved within 10 min. By using this method, pyrrolidinium cations in Songhua River and Hulan River were successfully extracted with the recoveries ranging from 74.2 to 97.1% and the enrichment factor assessed as 60. Pyrrolidinium cations with the concentration of 0.001?0.03 mg/L can be enriched and detected in the water samples. The developed method for the determination of pyrrolidinium ionic liquid cations in water samples is simple and reliable, which provides a reference for the study of the potential impact of ionic liquids on the environment. 相似文献
17.
M. Vahl Anette Graven René K. Juhler 《Fresenius' Journal of Analytical Chemistry》1998,361(8):817-820
A fast, sensitive and specific method for routine determination of residues from Chlormequat (CAS no. 7003-89-6) is described.
The method is based on a simple clean-up using an SPE-C18 cartridge, high-performance liquid chromatography on a standard C18 column (Spherisorb S5 ODS1) and specific detection and quantification by electrospray mass spectrometry (LC-MS/MS). 13C-Chlormequat was synthesised for use as internal standard. Samples were extracted with methanol – water – acetic acid. Internal
standard and ammonium acetate were added before C18-cartridge clean up and residues eluted with methanol – water – acetic acid, containing 50 mM ammonium acetate. Chromatographic
separation was achieved using a solvent composed of acetonitrile – methanol – water – acetic acid (53:21:25:1 by volume),
containing 50 mM ammonium acetate. Electrospray ionisation mass spectrometry was employed using m/z 58 (daughter ion of the
Chlormequat quaternary ammonium ion, m/z 122) and m/z 61 (daughter ion of the 13C-Chlormequat quaternary ammonium ion, m/z 125) for quantification. The LC analysis time was 15 min and the limit of detection
of the analytical method was 9 μg/kg. The performance of the method was demonstrated analysing grain material from an inter-comparison
study. In Denmark the primary use of Chlormequat chloride (CCC, cycocel, or chlorocholin chloride, CAS no. 999-81-5) is for
winter cereals and 11 such winter wheat samples from the Danish National Pesticide Survey were analysed. Residue contents
were from below 0.01 up to 0.45 mg/kg, and thus below the EU maximum residue level of 2.0 mg/kg for wheat.
Received: 22 December 1997 / Revised: 29 January 1998 / Accepted: 31 January 1998 相似文献
18.
Performance of ion chromatography in the determination of anions and cations in various natural waters with elevated mineralization 总被引:1,自引:0,他引:1
The performance of ion chromatography in the determination of anions and cations in natural mineral waters of different composition and different total mineralization was evaluated. Up to 12 ions of the 20 usually included in extended chemical analysis of natural waters were successfully determined by ion chromatography alone. At least 98.60% and up to 99.96% of total cation composition of mineral waters was determined by ion chromatography. Hydrogen carbonate predominated in anion composition of mineral waters and was determined titrimetrically. The percentage of anions determined by ion chromatography in the remaining anion composition of mineral waters was between 98.90% and 99.96%. The agreement between total concentrations of anions and cations in individual mineral waters determined predominantly by ion chromatography is very good and the performance of ion chromatography for the basic and for the extended chemical analysis of highly mineralized water samples is very high. Method development was assisted by previously developed algorithms and appropriate experimental conditions are also discussed. 相似文献
19.
A novel method for the determination of a PCB sum value by enzyme immunoassay to overcome the cross-reactivity problem 总被引:2,自引:0,他引:2
Andreas J. Schuetz M. G. Weller Reinhard Niessner 《Fresenius' Journal of Analytical Chemistry》1999,363(8):777-782
Many attempts have been made to detect polychlorinated biphenyls (PCBs) by enzyme immunoassay (ELISA). All known ELISAs to
PCBs show characteristic cross-reactivity problems. Without any prior information about the composition of the sample, no
quantification of the total PCB content is possible. A chemical approach is shown to solve the cross-reactivity problem by
the quantitative dechlorination of all PCB congeners to the single compound biphenyl. For the reductive dechlorination palladium
on barium sulfate and ammonium formate were used. The dechlorination procedure was optimized to be performed at room temperature
in methanol without the exclusion of oxygen or water. For the development of polyclonal biphenyl-antibodies the synthesis
of the hapten biphenylhexanoic acid via Grignard cross-coupling is described and an immunization protocol is given. The purity
of the used immunological reagents proved to be very crucial. The whole procedure was tested with spiked soil samples. The
detection limit for PCBs (Clophen A50) in soil was 1 mg/kg (3.1 μmol/kg). This corresponds to a biphenyl concentration in
methanol of 0.1 mg/L (0.6 μmol/L).
Received: 25 September 1998 / Revised: 1 December 1998 / Accepted: 4 December 1998 相似文献
20.
A column preconcentration method has been established for the spectrophotometric determination of traces of nitrite using
diazotization and coupling on an naphthalene-tetradecyldimethylbenzylammonium (TDBA)-iodide (I) adsorbent. Nitrite ion reacts
with sulfanilic acid (SA) in the pH range 1.8–3.0 for the SA-1-naphthol system and in the pH range 2.3–3.2 for the SA-1-naphthylamine-4-sulfonate
system (SA-NAS system) in hydrochloric acid medium to form water-soluble colourless diazonium cations. These cations were
coupled with 1-naphthol in the pH range 1.6–4.6 and with NAS in the pH range 2.6–5.0 to be retained on naphthalene-TDBA-I
packed in a column. The solid mass was dissolved from the column with 5 mL of dimethylformamide (DMF) and the absorbance measured
at 418 nm for the SA-1-naphthol system and at 485 nm for the SA-NAS system. The calibration curve was linear over the concentration
range 0.02–0.87 mg/L for SA-1-naphthol and 0.02–0.80 mg/L in the sample for SA-NAS. The molar absorptivity was calculated
to be 1.70×104 L mol-1 cm-1 for SA-1-naphthol and 1.66×104 L mol-1 cm-1 for SA-NAS. The detection limits were found to be 0.014 and 0.016 mg/L for SA-1-naphthol and SA-NAS, respectively. The preconcentration
factors were 8 and 6 for SA-1-naphthol and SA-NAS, respectively. Replicate determinations of seven sample solutions containing
6.6 μg of nitrite for SA-1-naphthol and 5.3 μg of nitrite for SA-NAS gave mean absorbances of 0.486 and 0.382 with relative
standard deviations of 0.49 and 0.58%, respectively. Interferences due to various foreign ions have been studied and the method
has been applied to the determination of 27–65 μg/L levels of nitrite in natural waters. The recovery and relative standard
deviation for water samples were 98–102% and 0.49–0.58% for both systems.
Received: 1 December 1995/Revised: 22 April 1996/Accepted: 22 April 1996 相似文献