Metal ions analysis

We have developed reverse-phase ion-pairing HPLC separations of substituted EDTA metal chelates of several transition metals (including Cd, Zn, Fb, and Hg) and several lanthanides (La, Ce, Eu, Dy, Er, Yb, Lu). Detection levels of these chelates are currently being assessed. A sensitive metal ion analysis employing an inherently fluorescent EDTA seems feasible. 

Chapter 14 Ion Chromatography Modes for Metal Ions Analysis.385... 

Detailed procedures for separating and identifying all the ions can be found in general chemistry laboratory manuals. Although modern methods of metal-ion analysis employ sophisticated analytical instruments, qualitative analysis is still included in many general chemistry laboratory courses because it is an excellent vehicle for developing laboratory skills and for learning about acid-base, solubility, and complex-ion equilibria. 

MICRO CHEMICAL REACTION AND EXTRACTION SYSTEM HEAVY METAL ION ANALYSIS... 

L9. Long, M. J., Metal ion analysis by emission spectroscopy of starch block electro-phoretically separated human serum proteins. Am. J. Med. Technol. 28, 241-256 (1962). 

Most applications of polarography involve metal ion analysis, where only one valence state is present in solution, such as Tl+, Cd2+, Pb2+, or Zn2+. However, that is not always the case one can analyze Fe2+and Fe3+simulta-neously by polarography, in a complexing solution such as made with oxalate, in which case the polarogram shows (at E< i/2) a limiting reduction current i due to the reduction of Fe3+to Fe2+, and (at E> EV2) a limiting oxidation current i for the oxidation of Fe2+to Fe3+. We simulate this in Fig. 6.10-2. 

Figure 11.8 Second-order response patterns of the pure, top graph, and mixture, bottom graph, metal ion analysis using the two-dimensional fiber optic probe. The pure component is the chelated absorbance spectra of lead over time. The mixture contains lead and various other metal ions.

Some authors mention that the polymer vessels are adequate for silica and metal ions analysis (Na+, K+, Ca+2, Mg+2, Ag+, Cd+2, Cu+2) but are unsuitable for dissolved permeable gases and for phosphates, that can be adsorbed. 

A85. Perini, F.R. Multiple transition metal ion analysis by ion chromatography in tobacco and related matrices ... 

Enzyme inhibition sensors are the most commonly reported enzyme-based biosensors for the detection of toxic compounds and heavy metal ions. The sensors are based on the selective inhibition of specific enzymes by classes of compounds or by the more general inhibition of enzyme activity. Most of the research carried out has been directed toward the detection of organophosphorus and carbamate insecticides and the triazine herbicides and metal ions analysis [72,73]. Several enzymes have been used in inhibition sensors for pesticides and heavy metal analysis using water, soil, and food samples including choline esterase, horseradish peroxidase, polyphenol oxidase, urease, and aldehyde dehydrogenase. 

FIGURE 5.6 The portable sensor system for metal ions analysis. Screen-printed sensor (fabricated at Cranfield University) conpled to a portable electrochemical instrnment (PalmSense, Palm Instruments BV). 

Y.-S. Fung and H.-S. Tung, Capillary electrophoresis for trace metal ion analysis on environmental... 

To overcome the problem of detection in CE, many workers have used inductively coupled plasma-mass spectrometry (ICP-MS) as the method of detection. Electrochemical detection in CE includes conductivity, amperometry, and potentiometry detection. The detection limit of amperometric detectors has been reported to be up to 10 M. A special design of the conductivity ceU has been described by many workers. The pulsed-amperometric and cyclic voltametry waveforms, as well as multi step wave forms, have been used as detection systems for various pollutants. Potentiometric detection in CE was first introduced in 1991 and was further developed by various workers. 8-Hydroxyquinoline-5-sulfonic acid and lumogallion exhibit fluorescent properties and, hence, have been used for metal ion detection in CE by fluorescence detectors. Overall, fluorescence detectors have not yet received wide acceptance in CE for metal ions analysis, although their gains in sensitivity and selectivity over photometric detectors are significant. Moreover, these detectors are also commercially available. Some other devices, such as chemiluminescence, atomic emission spectrometry (AES), refractive index, radioactivity, and X-ray diffraction, have also been used as detectors in CE for metal ions analysis, but their use is stiU limited. 

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