共查询到20条相似文献,搜索用时 31 毫秒
1.
B. Koppenhoefer Ulrich Epperlein Marc Schwierskott 《Analytical and bioanalytical chemistry》1997,359(1):107-114
The separation of enantiomers by gas chromatography on a chiral stationary phase is stored and conveniently retrieved in
the molecular database Chirbase/GC. According to the present information content (version 3/96), a great variety of analytes
has been published in several hundred journals. A selected review is given on 364 enantiomer separations of 102 different
molecules containing at least one four-membered saturated carbocyclic ring. Factors determining the degree of enantioseparation
are outlined and analyzed.
Received: 16 November 1996 / Revised: 17 April 1997 / Accepted: 30 April 1997 相似文献
2.
S. A. Nabi E. S. M. Abu-Nameh N. Rahman M. I. H. Helaleh 《Fresenius' Journal of Analytical Chemistry》1998,360(1):140-141
A simple, fast and sensitive titrimetric method has been developed for the determination of tetracycline hydrochloride in
human urine using m-dinitrobenzene as color agent and Dowex 1 × 8 as detection medium.
Received: 26 February 1997 / Revised: 23 April 1997 / Accepted: 29. April 1997 相似文献
3.
The capability of a modern interpretation system for IR spectra has been tested, in which the process of structural assignment
is modelled by methods of fuzzy logic. Figures of merit were generated for different interpretation algorithms. These figures
of merit permit the validation as well as a comparison of independent interpretation systems. The influence of the sample
preparation practice onto the information content of the resulting spectrum has been evaluated as well. Automatically generated
band tables show only restricted reliability.
Received: 13 February 1997 / Revised: 1 April 1997 / Accepted: 3 April 1997 相似文献
4.
The capability of a modern interpretation system for IR spectra has been tested, in which the process of structural assignment
is modelled by methods of fuzzy logic. Figures of merit were generated for different interpretation algorithms. These figures
of merit permit the validation as well as a comparison of independent interpretation systems. The influence of the sample
preparation practice onto the information content of the resulting spectrum has been evaluated as well. Automatically generated
band tables show only restricted reliability.
Received: 13 February 1997 / Revised: 1 April 1997 / Accepted: 3 April 1997 相似文献
5.
MS-Pep: a computer program for the interpretation of mass spectra of peptide libraries 总被引:1,自引:0,他引:1
S. Kienle K.-H. Wiesmüller J. Brünjes J. W. Metzger G. Jung 《Fresenius' Journal of Analytical Chemistry》1997,359(1):10-14
Electrospray mass spectrometry (ESI-MS) is an established method for the qualitative analysis of synthetic peptide libraries
and combinatorial mixtures or collections of small organic compounds. However, the calculation of the mass distribution of
even small peptide mixtures is a time-consuming and error-proned task. Therefore, the computer program MS-Pep has been developed,
which calculates the masses of expected peptides, byproducts and the mass distributions of peptide libraries.
Received: 2 December 1996 / Revised: 17 April 1997 / Accepted: 21 April 1997 相似文献
6.
R. Wennrich J. Mattusch P. Morgenstern T. G. Dzherayan V. M. Shkinev B. Y. Spivakov 《Fresenius' Journal of Analytical Chemistry》1997,359(2):161-166
The possibility of on-line membrane size-fractionation of water components and simultaneous separation of particulate and
dissolved matter at each filtration stage has been shown. The distribution patterns have been studied for As, Fe and Mn in
effluent samples of tin ore tailings (Altenberg, Saxony, Germany). The seepage composition is characterized by high concentrations
of Fe and As. The particulate and dissolved components were separated in five fractions between 0.025 and 8 μm. It was suggested
that the distribution patterns of As and Fe compounds depend on the chemical conditions at the sampling sites. Manganese exists
mainly in solvated forms in the liquid fractions.
Received: 8 January 1997 / Revised: 8 April 1997 / Accepted: 9 April 1997 相似文献
7.
2,6-O-diethyl-β-cyclodextrins were prepared and immobilized onto silica gel to develop a fluorosensor for dipyridamole. The
analytical performance characteristics of the proposed sensor for analysis of dipyridamole were as follows: the detection
limit was 0.8 nmol/L with a relative standard deviation of 1.4% for 10 determinations of 50 nmol/L of dipyridamole. The modification
of β-CD improved the sensitivity and selectivity for measuring dipyridamole. The recommended method has been successfully
tested for the determination of dipyridamole in clinical samples (urine and pharmaceutical preparations).
Received: 23 January 1997 / Revised: 14 April 1997 / Accepted: 21 April 1997 相似文献
8.
Bernd Spangenberg 《Fresenius' Journal of Analytical Chemistry》1998,360(2):148-151
An algorithm is presented that has successfully been utilized in practice for several years. It improves data analysis in
chromatography. The program runs in an extremely reliable way and evaluates chromatographic raw data with an acceptable error.
The algorithm requires a minimum of preliminaries and integrates even unsmoothed noisy data correctly.
Received: 7 April 1997 / Revised: 23 May 1997 / Accepted: 4 June 1997 相似文献
9.
P. Bode O. Lakmaker P. van Aller M. Blaauw 《Fresenius' Journal of Analytical Chemistry》1998,360(1):10-17
Instrumental neutron activation analysis (INAA) can now directly be applied to samples with masses in the kilogram range.
It enables the analysis of material which is considered to be not representative at the scale of the traditional analytical
portion, but representative at much larger scale. Large sample INAA (LS-INAA) circumpasses various problems associated with
sample-size reduction and homogenization. Examples of feasibility studies are given as on construction waste, contaminated
soil, harbour sediment and recyclable material. Also the economics of this method of analysis is discussed.
Received: 30 October 1996 / Revised: 3 April 1997 / Accepted: 16 April 1997 相似文献
10.
You-Qun Song R. Yuan M. Ying Zhi-Qiang Li Y.-Q. Chai H. Cui G.-L. Shen Ru-Qin Yu 《Fresenius' Journal of Analytical Chemistry》1998,360(1):47-51
A new PVC membrane electrode based on the bis(benzoin)-semiethylenediamine (BBSEA) complex of Hg(II) is described which exhibits
excellent selectivity towards iodide, related to the unique interaction between the central Hg(II) and the iodide ion. The
electrode has a linear response to iodide from 5 × 10–7 to 5 × 10–4 mol/L with a slope of 58 mV/dec.(20°C). The response characteristics were investigated in detail and the mechanism of the
electrode was studied with AC impedance and quartz crystal microbalance (QCM) techniques. It can be used for iodide determinations
in drug preparations.
Received: 29 January 1997 / Revised: 17 April 1997 / Accepted: 20 April 1997 相似文献
11.
T. Wiedmann H. Schimmel K. Ballschmiter 《Fresenius' Journal of Analytical Chemistry》1998,360(1):117-119
It has been shown that the concept of molar response, which is applicable to single ion monitoring of M+, can also be employed for ion trap MS/MS measurements, simplifying the determination of PCDD/PCDF by an extended IDA approach.
Received: 22 April 1997 / Revised: 16 June 1997 / Accepted: 18 June 1997 相似文献
12.
ICP-MS – A powerful analytical technique for the analysis of traces of Sb, Bi, Pb, Sn and P in steel
The determination of Sb, Bi, Sn, Pb and P in steel using quadrupole- and double-focusing-sector-field-ICP-MS is described.
Simple and fast methods for sample preparation were developed with regard to requirements of ICP-MS. Several certified steel
reference materials were analyzed in order to verify the accuracy and precision of the applied methods.
Received: 22 April 1997 / Revised: 19 June 1997 / Accepted: 23 June 1997 相似文献
13.
A novel experimental method for the assessment of the escape probability of photoelectrons as a function of depth and their
mean escape depths is described and illustrated for photoelectrons leaving an aluminium oxide surface. The results are compared
with those of the straight line approximation model calculations.
Received: 30 July 1997 / Revised: 7 April 1998 / Accepted: 8 April 1998 相似文献
14.
S. Lustig B. Michalke W. Beck P. Schramel 《Fresenius' Journal of Analytical Chemistry》1998,360(1):18-25
1. An on-line hyphenation of reversed phase high-performance liquid chromatography (RP-HPLC) with inductively coupled plasma-mass
spectrometry (ICP-MS) is applied, using an ultrasonic nebuliser combined with a membrane desolvator as the interface. Thus,
organic solvents (e.g. methanol, hexane) or gradients (e.g. methanol/water) as well as aqueous NaHCO3/NaCl mixtures can be directly used without influence on the plasma. The high resolution power of HPLC enables the separation
of Pt-species, whereas ICP-MS is taken for element specific detection with low detection limits. 2. Additionally, a powerful
on-line coupling of capillary electrophoresis (CE) and ICP-MS [1, 2] was used for platinum speciation in parallel. With these
two methods, independent from each other, first characterisation is achieved about the nature of Pt species formed by interaction
with a soil. Aqueous extracts of a clay-like humic soil, treated with a Pt contaminated tunnel dust and Pt model compounds
[3] were examined to elucidate transformation processes of Pt-species in a soil.
Received: 19 February 1997 / Revised: 15 April 1997 / Accepted: 18 April 1997 相似文献
15.
A kinetic spectrophotometric method for the determination of molybdenum is based on its catalytic effect on the oxidation
of pyrogallol red with hydrogen peroxide. The decrease of the absorbance of pyrogallol red in the presence of hydrogen peroxide
with time from 0.5 to 4.5 min is proportional to the concentration of Mo(VI) over the range 0.010–0.500 μg/mL. The limit of
detection is 0.008 μg Mo/mL. The precision and the effect of the presence of more than forty ions on the molybdenum determination
are reported. Probable interferences are completely removed by a cation exchange resin. The procedure was successfully applied
to the determination of molybdenum in plant materials and steels.
Received: 28 April 1997 / Revised: 16 June 1997 / Accepted: 18 June 1997 相似文献
16.
A kinetic spectrophotometric method for the determination of molybdenum is based on its catalytic effect on the oxidation
of pyrogallol red with hydrogen peroxide. The decrease of the absorbance of pyrogallol red in the presence of hydrogen peroxide
with time from 0.5 to 4.5 min is proportional to the concentration of Mo(VI) over the range 0.010–0.500 μg/mL. The limit of
detection is 0.008 μg Mo/mL. The precision and the effect of the presence of more than forty ions on the molybdenum determination
are reported. Probable interferences are completely removed by a cation exchange resin. The procedure was successfully applied
to the determination of molybdenum in plant materials and steels.
Received: 28 April 1997 / Revised: 16 June 1997 / Accepted: 18 June 1997 相似文献
17.
1. An on-line hyphenation of reversed phase high-performance liquid chromatography (RP-HPLC) with inductively coupled plasma-mass
spectrometry (ICP-MS) is applied, using an ultrasonic nebuliser combined with a membrane desolvator as the interface. Thus,
organic solvents (e.g. methanol, hexane) or gradients (e.g. methanol/water) as well as aqueous NaHCO3/NaCl mixtures can be directly used without influence on the plasma. The high resolution power of HPLC enables the separation
of Pt-species, whereas ICP-MS is taken for element specific detection with low detection limits. 2. Additionally, a powerful
on-line coupling of capillary electrophoresis (CE) and ICP-MS [1, 2] was used for platinum speciation in parallel. With these
two methods, independent from each other, first characterisation is achieved about the nature of Pt species formed by interaction
with a soil. Aqueous extracts of a clay-like humic soil, treated with a Pt contaminated tunnel dust and Pt model compounds
[3] were examined to elucidate transformation processes of Pt-species in a soil.
Received: 19 February 1997 / Revised: 15 April 1997 / Accepted: 18 April 1997 相似文献
18.
M. M. Kamal 《Fresenius' Journal of Analytical Chemistry》1998,360(1):112-116
The adsorption and accumulation of NADH and the Cu2+-NADH system at the mercury electrode surface was examined using differential pulse cathodic stripping voltammetry (DPCSV).
The method was developed for analytical trace determination of NADH. Experimental and operational parameters for the quantitative
determination of NADH were optimized and the detection limit was found to be 9.960 × 10–8 mol/L. The effect of some interferences (e.g. purine compounds, amino acids and some metal ions) was considered.
Received: 3 January 1997 / Revised: 1 April 1997 / Accepted: 4 April 1997 相似文献
19.
M. M. Kamal 《Analytical and bioanalytical chemistry》1998,360(1):112-116
The adsorption and accumulation of NADH and the Cu2+-NADH system at the mercury electrode surface was examined using differential pulse cathodic stripping voltammetry (DPCSV).
The method was developed for analytical trace determination of NADH. Experimental and operational parameters for the quantitative
determination of NADH were optimized and the detection limit was found to be 9.960 × 10–8 mol/L. The effect of some interferences (e.g. purine compounds, amino acids and some metal ions) was considered.
Received: 3 January 1997 / Revised: 1 April 1997 / Accepted: 4 April 1997 相似文献
20.
Dazhong Shen Songmin Peng Qi Kang Yanhui Xue 《Fresenius' Journal of Analytical Chemistry》1998,361(5):424-428
The adsorption process of dodecylammonium chloride (DAC) from aqueous solutions onto a quartz crystal interface was investigated
in situ using an electrode-separated piezoelectric sensor (ESPS). Increasing amounts of DAC adsorbed onto a quartz crystal surface
resulted in linearly decreasing oscillating frequencies of the ESPS. The adsorption density can be monitored by the frequency
decrease. The adsorption density obtained by calculation using the Sauerbrey equation in the ESPS method is greater than that
in solution depletion method. A calibration coefficient is added into the Sauerbrey equation to correct the influence of surface
roughness of the quartz crystal on the adsorption density. The influence of solution properties on the adsorption density
measurement was discussed. A dependence of the adsorption density on pH was reported.
Received: 17 April 1997 / Revised: 1 December 1997 / Accepted: 7 December 1997 相似文献