Detection of inorganics

The primary attraction of CL detection of inorganic compounds is the excellent sensitivity that can be obtained over a wide dynamic range using simple instruments. A detection limit of 40 pg/mL gold in ore samples reported by us is a striking example to indicate the advantage of CL detection [1],... 

Conductance monitors can be used where the sample components are ionic and providing that the conductivity of the mobile phase is very low. They are used extensively in ion chromatography (p. 147) for the detection of inorganic anions, some inorganic cations and ionized organic acids. 

A kit solution based on a volatile buffer for MS application and a coating solution granting high EOF reproducibility Kit solution for the indirect detection of inorganic and organic anions with metal cations (e.g., Ni " ", Cu " ", Co ) in plating bath solutions... 

Johns, C., Shaw, M. J., Macke, M., and Haddad, P. R. (2003). Sensitive indirect photometric detection of inorganic and small organic anions by capillary electrophoresis using Orange G as a probe ion. Electrophoresis 24, 557—566. 

Riter LS, Charles L, Turowski M, Cooks RG (2001) External interface for trap-and-release membrane introduction mass spectrometry applied to the detection of inorganic chloramines and chlorobenzenes in water. Rapid Commun Mass Spectrom 15 2290-2295... 

The device F is a detector as shown in Fig. 1. Since solutions of tppts and other aryl-group containing water-soluble phosphines absorb UV light strongly, it is better to use a refractometer than usual UV detectors. A refrac-tometer facilitates the detection of inorganic salts such as sodium chloride and sodium sulfate. Here refractometers from Biichi were used and operated with regular x/f-recorders (G). 

Indirect UV is the most common mode for the detection of inorganic anions and cations by CE. Pyromellitic acid or chromate are the most... 

Figure 6.9 Indirect UV detection of inorganic cations by CE. Conditions electrolyte, UVCat2 with tropolone as the complexing agent (pH 4.4) detection, indirect UV absorbance at 190 nm capillary, 60 cm X 75 /urn I.D. fused silica. Peaks 1, Potassium 2, Barium 3, Strontium 4, Calcium 5, Sodium 6, Magnesium 7. Lithium. (Reprinted from Ref. 10 with permission.)...

A satisfactory test for the identification of FDR on a suspected firer has been sought by forensic scientists for many years. A satisfactory test would be one that is simple, reliable, fast, inexpensive, and conclusive. Until recently efforts have concentrated mainly on the detection of inorganic components of FDR and encompass qualitative and quantitative methods, culminating in the particle analysis method, which is the most informative method currently available. A brief outline of the most important developments follows. 

On the basis of this work there is poor correlation between the detection of inorganic and organic FDR in casework, and organic detection appears to be more sensitive than the detection of inorganics. However, one of the cases examined (FI) was atypical and consisted of 100 exhibits consequently there are insufficient data to draw firm conclusions about the value of organic FDR detection. 

Bayer and his associates 16) are of the opinion, however, that the inorganic sulfide is of amino acid origin, being released from cysteine when ferredoxin is denatured. They reported the detection of inorganic sulfide from certain synthetic cysteine-iron derivatives, as well as a reconstitution of ferredoxin after the iron had been completely removed by treatment with a,a -dipyridyl. Since these data are in conflict with those discussed above, the resolution of this discrepancy will be awaited with interest. 

The separations of many volatile substances for inorganic analysis has been described in the literature However, only a small proportion of these publications deal with the possibilities and applications of trace analysis. The reasons for this lie in the difficulty of sensitive detection of inorganic compounds, their instability and the low volatility of many of them, and in the numerous interfering effects in the chromatographic column. 

Among the membrane-based assay systems, the ATPase assay can be used to identify ABC substrates, since ABC transporters require ATP to transport substrates across the cell membrane. Using isolated membranes containing the ABC transporter of interest or reconstituted ABC protein preparations, ABC substrates would be revealed by an observed increase in ATPase activity (colorimetric detection of inorganic phosphate). In an alternative, inhibition-type (indirect) setup, the test compound is added to a well-established ABC substrate, which creates high ATPase activity. If the test compound is also an ABC substrate, the increased ATPase activity will decrease. 

The kind of eluent that is used for anion exchange chromatography depends mainly on the detection system being employed. Since, in many cases, the detection of inorganic and organic anions occurs via conductivity detection, the eluents used are classified into two groups ... 

Suitably modified fiber optic sensors can also be used for detecting gas vapors, humidity, ions, and organic compounds. Fiber inclusions that show length variation were used to develop humidity sensors, whereas ion-responsive lipid bilayers formed the basis for the detection of inorganic ions. Immobilized neutral and ionic crown ethers in polymeric membranes were designed as sensors for determination of barium and copper (Wolfbeis 2000). 

A sodium molybdate eluent with indirect detection at 250 nm was found to provide an excellent separation and a very sensitive detection of inorganic anions. The separa-... 

P. R. Haddad and R. C. Foley, Aromatic bases as eluent components for conductivity and indirect ultraviolet detection of inorganic cations in non-suppressed ion chromatography. Anal. Chem., 61, 1435,1989. 

Chromate at a concentration of around 5 mM has been used very successfully for indirect detection of common inorganic anions at a wavelength of 254 nm. A now classic separation of some 30 anions in a single run is illustrated in Fig. 10.2. More recently, Shamsi and Danielson have proposed naphthalenedisulfonate (NDS) and naphthalenetrisulfonate (NTS) for indirect detection of inorganic and organic anions... 

AR Timerbaev. Advances in detection of inorganic ions in capillary electrophoresis. J Capillary Electrophor 5 185-192, 1998. 

It is important to note that these methods are typically unable to distinguish among various dithiocarbamates since most can be degraded to CS2. Other methods for determination of maneb or mancozeb, which are ethylenebisdithiocarbamates, or EBDCs, rely on the measurement of the metallic portion of the compounds, and therefore, many of these methods are similar to those for detection of inorganic manganese. Some newer methods are presented that have greater selectivity or use novel approaches different from carbon disulfide evolution. 

A large number of optodes developed for the selective detection of inorganic anions and cations, so-called ion-selective optodes (see Table 13.2), consist of polymer membranes that contain transducers. The latter are mostly physically admixed, but in some cases they are covalently bound to the polymer matrix. Most of these optodes [7, 8] are based on poly(vinyl chloride), plasticized with DOS, BBPA, DOP, o-NPOE or other plasticizers (see Chart 13.3). Typically, membranes are composed of 33 wt.% PVC, 66 wt% plasticizer, and 1 wt% ionophore (analyte-complexing agent) and lipophilic salt (ion-exchanger). Other polymers occasionally employed in hydrophobic optodes include polysiloxanes and poly(vi-... 

This type of detector is used in ion chromatography for the detection of inorganic anions (e.g., S04, PO43 ), some inorganic cations (e.g Ca +, Mg2+), and some ionised organic acids. This is due to the fact that all ions are electrically conducting. Conductivity detectors are based on the conductance of an eluent prior to and during the elution of the analyte from the column. 

Dion, H.M. Ackerman, L.K. HUl, H.H., Jr., Detection of inorganic ions from water by electrospray ionization-ion mobility spectrometry, Talanta 2002,57, 1161-1171. 

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