Interference silicate

Dispersants andfloeculants. These are important for the control of slimes that sometimes interfere with the selectivity and increase reagent consumption. For example, soda ash, lime sodium silicate, and lignin sulfonates are used as dispersants, and starch and polyacrylamide are used as flocculants. 

The second method is the flow-coulometry and can be applied to orthophosphates with concentrations of 5x10 1x10 M contained in the interstitial water in sediments. The advantage of this method is that only small amounts of sample ( 100 p.1) are needed and the analytical results are entirely free from interference due to silicate ions. 

An alternative to the bridge technique was recently reported for thorium analysis in silicate rocks for which both Th and Th are measured on a single lon-counting detector (Rubin 2001). With careful chemistry and mass spectrometry, °Th/ Th ratios of igneous rocks can be measured with this technique with a precision that is similar to the bridge method. The disadvantage of this technique is that °Th ion-count rates are extremely low (around 10 cps) with normal silicate thorium ratios and are therefore subject to perturbations from background variation and low-level isobaric interferences in normal samples. 

Tennessee ball clay was the only extending material which when in composition with DDT appeared to interfere appreciably with the removal of DDT surface residues by sodium silicate washes. 

Brewer and Spencer [428] have described a method for the determination of manganese in anoxic seawaters based on the formulation of a chromophor with formaldoxine to produce a complex with an adsorption maximum at 450 nm. Sulfide (50 xg/l), iron, phosphate (8 ig/l), and silicate (100pg/l) do not interfere in this procedure. The detection limit is 10 pg/1 manganese. 

Subsequent work showed that a modification of the synthesis procedure produced a 10A hydrate which> if dried carefully, would maintain the interlayer water in the absence of excess water (27). This material is optimal for adsorbed water studies for a number of reasons the parent clay is a well-crystallized kaolinite with a negligible layer charge, there are few if any interlayer cations, there is no interference from pore water since the amount is minimal, and the interlayer water molecules lie between uniform layers of known structure. Thus, the hydrate provides a useful model for studying the effects of a silicate surface on interlayer water. 

Matrix effects in the analysis of nutrients in seawater are caused by differences in background electrolyte composition and concentration (salinity) between the standard solutions and samples. This effect causes several methodological difficulties. First, the effect of ionic strength on the kinetics of colorimetric reactions results in color intensity changes with matrix composition and electrolyte concentration. In practice, analytical sensitivity depends upon the actual sample matrix. This effect is most serious in silicate analysis using the molybdenum blue method. Second, matrix differences can also cause refractive index interference in automated continuous flow analysis, the most popular technique for routine nutrient measurement. To deal with these matrix effects, seawater of... 

KaoUn powder and other hydrated aluminum silicate clays, often combined with pectin (a complex carbohydrate), are the most widely used adsorbent powders (e.g., Kaopectate). Kaolin is a naturally occurring hydrated aluminum silicate that is prepared for medicinal use as a very finely divided powder. The rationale behind its use in acute nonspecific diarrhea stems from its ability to adsorb some of the bacterial toxins that often cause the condition. It is almost harmless and is effective in many cases of diarrhea if taken in large enough doses (2-10 g initially, followed by the same amount after every bowel movement). The adsorbents are generally safe, but they may interfere with the absorption of some drugs from the GI tract. 

Most of the successful rare earth activated phosphors comprise host lattices in which the host cation is also a rare earth. A principal reason for this relates to the optical inertness of La, Gd, Y, and Lu this is essential to avoid interference with activator emission spectra. Close chemical compatibility including amenability to substitutional Incorporation of rare earth activators are also essential features. Rare earth hosts such as oxides, oxysulfides, phosphates, vanadates and silicates also tend to be rugged materials compatible with high temperature tube processing operations and salvage. 

Van den Boom et al.150 have reported on the determination of silicon isotope ratio measurements in silicate materials by MC-ICP-MS (at a mass resolution of 2500 to resolve isobaric interferences) after sodium hydroxide sample digestion and purification of silicon. 829Si and 830Si have been determined for several silicon isotope standard reference materials. A precision for 830Si of 0.18-0.41 %o was achieved. Precise and accurate measurements of isotope ratios on transient signals by HPLC-MC-ICP-MS for nuclear application was performed by Giinther-Leopold et al.151... 

Siliceous materials—Si, Al, Fe, Ti, Ca, Mg, Na, K, Mn, Ni, Ba, Ag, Au, Ca, Cr, Cu, Ga, In, Mo, Sb and Zn—may be analyzed by a lithium tetraborate fusionr-acid dissolution technique using atomic absorption spectroscopy. Mercury, tin, and lead volatilize by this technique, and gold and silver in concentrations above 0.5 wt% cannot be held in solution. Coal ash is preconcentrated prior to analysis, and there is possible silica interference. Analytical results, where possible, are compared statistically with other reported values. 

Although prior research has established the interference effect of aluminum, previous in-house studies on the atomic absorption analysis of silicate materials indicated that silicon may also have an interference effect. This interference is probably caused by compound formation in the flame. The effect of silicon on the determination of all of the elements... 

The primary source of aluminum is the mineral bauxite, which is found in large deposits in Australia, Jamaica, and Sumatra. Transportation costs are high, and many steps are required to process the ore. Because bauxite ore is usually contaminated with the oxides of iron, titanium, and silicon, pretreatment is required before extraction of the metal can begin. The crude bauxite must be crushed, washed, and dried in a kiln to free it from silicate clays, which interfere with later purification steps. 

Silicate, chromate, molybdenate, and humic acids also may create significant interferences with the sorption of As(V) and As(III) on zerovalent iron (Su and Puls, 2001b Giasuddin, Kanel and Choi, 2007). Interferences from borate and sulfate, however, were negligible with As(V) and only minor with As(III). Some interferences with As(III) and As(V) sorption occurred with carbonate and nitrate (Su and Puls, 2001b). Similarly, Farrell et al. (2001) concluded that carbonate and nitrate could hinder the efforts of zerovalent iron to lower As(V) concentrations in water to below 5 pgL-1. 

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