Matrix elimination

Figure 5.4 Schematic diagrams of a heait-cut valve configuration system. Reprinted from Journal of Chromatography, 602, S. R. Villasenor, Matrix elimination in ion cliromatography by heart-cut column switching techniques , pp. 155-161, copyright 1992, with permission from Elsevier Science.

S. R. Villasenoi, Matrix elimination in ion chromatography by heart-cut column switcliing techniques , 7. Chromatogr. 602 155-161 (1992). 

Generally speaking, Newton s method may be employed for nonlinear difference equations on every new layer, but the algorithm of the matrix elimination for a system of two three-point equations (see Chapter 10, Section 1) suits us perfectly for this exceptional case. We will say more about this later. 

Proper evaluation of the necessary actions in solving problem (5) by the matrix elimination method is stipulated, as usual, by the special structures of the matrices involved. Because all the matrices are complete in spite of the fact that C is a tridiagonal matrix, O(iVf) arithmetic operations are required for determination of one matrix on the basis of all of which are known to us in advance. Thus, it is necessary to perform 0 Ni N2) operations in practical implementations with all the matrices j = 1,2,N-2- Further, 0 N ) arithmetic operations are required for determination of one vector with knowledge of and 0 Nf N2) operations for determination of all vectors Pj. 

Determination of Perchlorate in Drinking Water using Inline Column Concentration/Matrix Elimination Ion... 

Fig. 7.8 Schematic flowchart of the competitive MS-binding assay quantifying the nonbound marker employed for dopamine D2 receptors including matrix elimination. After incubation of the target (D2 receptor) in presence of the marker (spiperone) and a test compound, the binding samples are centrifuged to separate bound from nonbound marker. The nonbound marker in the resulting supernatant is quantified after SPE by LC-ESI-MS/MS.

Zakaria P., Bloomfield C., Shellie R. A, Haddad P. R Dicinoski G. W. Determination of bromate in sea water using multi-dimensional matrix-elimination ion chromatography. Journal of Chromatography A 2011 1218(50) 9080-9085. 

The method of matrix elimination. The system of equations (3) is one particular case of the following problem ... 

Every coupling application favors one part of the coupling system. A dominating chromatography part leads to the speciation analysis [5,6,26,27]. The elemental specific detection facilities of atomic spectrometry are strongly favored over the multielement capabilities. An inversion of this construction leads to multielement trace analysis in complex matrices with the use of chromatographic equipment as powerful preconcentration and matrix elimination tool [13k The ability of chromatography for a further time resolution between the separated traces is not really required because of the excellent elemental specific detection capabilities of atomic spectrometry. 

Fig. 1. Trace bromate determination using matrix elimination and preconcentration. See text for details. Peaks 1, fluoride 1.0 mg/1 2, unknown 3, chlorite, 0.01 mg/1 4, bromate 0.005 mg/1 5, chloride, 200 mg/1 6, nitrite 0.1 mg/1 7, bromide, 0.01 mg/1 8, chlorate, 0.01 mg/l 9, nitrate, 10.0 mg/l 10, o-phosphate, 0.1 mg/l 11, sulfate, 200 mg/l. Sample B was pretreated with OnGuard II Ag, H cartridges. Samples also contained 200 mg/l bicarbonate.

Off-line sample pretreatment in ion chromatography most often involves matrix elimination using... 

Polymeric reversed phase resins are synthesized from divinylbenzene with styrene, methylstyrene or other styrenic monomers. Divinylbenzene is the major component and provides crosslinking. These resins are macroporous, and the surface area is usually in excess of 300 m2 / g. This surface area provides the adsorptive surface for retention of hydrophobic species. These resins can be used for matrix elimination of surfactants, weak carboxylic acids, fats, proteins, etc. 

The determination of iodide in milk (2% milkfat) by ion chromatography coupled with pulsed amperometric detection on a silver electrode is an application that benefits from matrix elimination of fats. The pulsed amperometric waveform improves reproducibility by electrochemically cleaning the working electrode on each pulse. In addition, the fats are removed from the sample using a disposable cartridge containing a polymeric reversed phase resin (OnGuard II RP, Dionex Corp.). When 50 jal of 0.1 mg/1 iodide was added to 200 jal of prepared milk, the recovery was 100%. The iodide peak area and retention time RSDs were 1.4% and 0.4% respectively [28]. 

Several different approaches to preconcentration and matrix elimination have been reported. A commercially available chelation system based on silica-immobilized 8-hydroxyquinoline has been used for on-line preconcentration and matrix separation [315,316]. Detection limits using a 90-fold concentration were 0.04 ng/dm3 for U to 6.3 ng/dm3 for Zn. 

Our overall approach to matrix elimination and Am and Pu preconcentration is shown in Figure 2. One hundred grams of a dried Northern Illinois soil sample is muffled at 500"C for 3 hours in a glass beaker. Four hundred pg of Sm(III) and the appropriate amounts of Pu(III)/(IV) and Am(III) tracers are added to the muffled soil sample. The sample is then leached with 300 mL of 6 M HCl at 90 C for 2 hours with stirring. After cooling, the supernatant is separated by centrifugation for 15 minutes at 5000 rpm. The residue is washed two successive times with 75 mL of 6 M HCl and the combined supernatant plus rinses (-450 mL) is filtered to eliminate any suspended particles. 

Pretty, J.R. Deng, H. Goeringer, D.E. Van Berkle, G.J. Electrochemically Modulated Preconcentration and Matrix Elimination for Organic Analytes Coupled On-Line with Electrospray Mass Spectrometry, Anal. Chem. 72,2066-2074 (2000). 

Marhcni, P. R. Haddad and A. R. McTaggart, On-column matrix elimination of high levels of chloride and sulfate in non-supprcssed ion chromatography, / Chromatogr., 546,221, 1991. 

Among the advantages of using radiotracers we can list the following (a) radiotracers are easy to detect and measure with high precision to sensitivities of to 10" g (b) the radioactivity is independent of pressure, temperature, chemical and physical state (c) radiotracers do not affect the system and can be used in nondestructive techniques (d) if the tracer is radiochemically pure, interference from other elements is of no concern (common in ordinary chemical analyses) (e) for most radioisotopes the radiation can be measured independently of the matrix, eliminating the need for calibration curves. 

A matrix elimination IC with postcolumn reaction detection was developed for the determination of iodide in seawater (Brandao et al, 1995). A Dionex lonPac ASH anion-exchange column was used, and the mobile phase contained sodium chloride to remove interference of the... 

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