Aluminium, analytical determination

The analytical determination of aluminium (complexometrically after the hydrolysis) and of hydride hydrogen (volumetrically after decomposition with an acid) is sufficient for the determination of the concentration and the quality of the product in the solution. ... 

Schetinger MRC, Morsch VM, Bohrer D (2003) Aluminium Interaction with Nucleotides and Nucleotidases and Analytical Aspects of Determination 104 99-138 Schmidtke HH (2003) The Variation of Slater-Condon Parameters Fk and Racah Parameters B and C with Chemical Bonding in Transition Group Complexes 106 19-35 Schubert DM (2003) Borates in Industrial Use 105 1-40... 

Vandecasteele et al. [745] studied signal suppression in ICP-MS of beryllium, aluminium, zinc, rubidium, indium, and lead in multielement solutions, and in the presence of increasing amounts of sodium chloride (up to 9 g/1). The suppression effects were the same for all of the analyte elements under consideration, and it was therefore possible to use one particular element, 115indium, as an internal standard to correct for the suppressive matrix effect, which significantly improved experimental precision. To study the causes of matrix effect, 0.154 M solutions of ammonium chloride, sodium chloride, and caesium chloride were compared. Ammonium chloride exhibited the least suppressive effect, and caesium chloride the most. The results had implications for trace element determinations in seawater (35 g sodium chloride per litre). 

The determination of an inorganic analyte in an inorganic matrix, e.g. aluminium in rocks, requires the use of classical methods of separation, possibly complexation and a final determination which is designed to remove the effect of interferents by use of a specific chemical reaction(s) or spectrophotometric measurement at a wavelength which is specific to the analyte to be determined. Even so, the ability of this approach to eliminate interference from other elements (or compounds) must be established. 

Notwithstanding the excellent analytical features inherent in molecular phosphorimetric measurements, their use has been impeded by the need for cumbersome cryogenic temperature techniques. The ability to stabilize the "triplet state" at room temperature by immobilization of the phosphor on a solid support [69,70] or in a liquid solution using an "ordered medium" [71] has opened new avenues for phosphorescence studies and analytical phosphorimetry. Room-temperature phosphorescence (RTF) has so far been used for the determination of trace amounts of many organic compounds of biochemical interest [69,72]. Retention of the phosphorescent species on a solid support housed in a flow-cell is an excellent way of "anchoring" it in order to avoid radiationless deactivation. A configuration such as that shown in Fig. 2.13.4 was used to implement a sensor based on this principle in order to determine aluminium in clinical samples (dialysis fluids and concen-... 

The presence of low concentrations of phosphate has long been known to interfere with other fluorimetric analytical procedures this ability of trace amounts of phosphate to quench the fluorescence of chelates has been applied to the determination of the phosphates themselves. Several chelates were investigated measurement of the decrease of fluorescence of the aluminium-morin complex after phosphate addition proved to give the most satisfactory results65 (see Section II.B.2.a). 

This is by far the most frequently encountered interference in AAS. Basically, a chemical interference can be defined as anything that prevents or suppresses the formation of ground state atoms in the flame. A common example is the interference produced by aluminium, silicon and phosphorus in the determination of magnesium, calcium, strontium, barium and many other metals. This is due to the formation of aluminates, silicates and phosphates which, in many instances, are refractory in the analytical flame being used. 

In flameless atomic absorption the analyte often tends to react with the graphite furnace or rod to form carbides. In such cases atomisation is suppressed. Release agents are used to react preferentially with the graphite releasing the analyte on atomisation. An application of this is in the determination of aluminium, barium, beryllium, silicon and tin. A large enhancement of the signal has been observed [47] when calcium (as the nitrate) is added to the analytical solutions. This has been suggested as due to a reduction in the formation of carbide in the presence of calcium. A calcium level of 1000 to 2000 mg l-1 in the solutions has been reported as the optimum in most cases. 

Future goals for the increased use of atomic absorption are the production of simple general methods and the further simplification of analytical techniques. One example is the determination of acid-soluble aluminium in steel, which is still significant during steel production. With the help of a con-... 

A solution of the element of interest, 1 ppm (10 ppm and 20 ppm for lead and aluminium, respectively) in 10 M hydrochloric acid was determined by AAS. A similar solution of this element was then prepared in the presence of 500 ppm of the interfering element and the atomic absorption signal compared with the blank solution. If the analytical signal did not change by more than 5%, then the element was regarded as not having a significant interference effect on the analyte element. 

Sauerbrei (1988) developed a multi channel calorimeter for the determination of up to three different analytes. A two point controller grossly thermostats the aluminium cylinder to a desired temperature, and a PI controller ensures fine tuning. A multiple bridge is connected with an amplifier and an 8-bit A/D board, and a microprocessor takes care of data acquisition and analysis (peak height and area). 

Chrome azurol S was used to determine A1 in tap water, dialysis fluids and alkali metal salts [1] and in mine well water [2]. The preliminary preconcentration of the eomplex on a polyethylene powder was applied [1]. Aluminium species (Al(III) ions and Ali304(0H)24 (H20)i2 ) in aqueous soil extracts and humic waters were determined by FIA method using Chrome azurol S after preliminary retaining of the analyte on a column reactor containing 8-quinolinol immobilized onto Fractogel and selective elution with different elluents [3]. 

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