Wickbold

Total sulfur NF EN 24260 ISO 4260 ASTM D 2785 Combustion in Wickbold burner and analysis... 

Poloxamers are used primarily in aqueous solution and may be quantified in the aqueous phase by the use of compleximetric methods. However, a major limitation is that these techniques are essentially only capable of quantifying alkylene oxide groups and are by no means selective for poloxamers. The basis of these methods is the formation of a complex between a metal ion and the oxygen atoms that form the ether linkages. Reaction of this complex with an anion leads to the formation of a salt that, after precipitation or extraction, may be used for quantitation. A method reported to be rapid, simple, and consistently reproducible [18] involves a two-phase titration, which eliminates interferences from anionic surfactants. The poloxamer is complexed with potassium ions in an alkaline aqueous solution and extracted into dichloromethane as an ion pair with the titrant, tet-rakis (4-fluorophenyl) borate. The end point is defined by a color change resulting from the complexation of the indicator, Victoria Blue B, with excess titrant. The Wickbold [19] method, widely used to determine nonionic surfactants, has been applied to poloxamer type surfactants 120]. Essentially the method involves the formation in the presence of barium ions of a complex be-... 

R. Wickbold, Proc. lVth Int. Congress on Surface Active Substances, Vol. 3, Brussels, 1964, pp. 903-912. 

Combustion Calorimetric bomb (Berthelot), oxygen flask (Schoniger), Wickbold apparatus, cold plasma incinerator, micro-Dumas combustion (CHN analyser), sulfur-specific analysers (S, C, N, O), pyrochemiluminescence... 

In the Wickbold method, solid samples are vaporised in an oxygen stream and fed into an oxyhydrogen flame, which bums in a cooled quartz tube. The combustion products are condensed here, or are captured in an absorption solution as gaseous materials. Although combustion in a Wickbold apparatus is a quick and effective method for destroying organic material of all types, incomplete destruction may occur [19]. In special digestion vessels, known as cold-plasma ashers (CPA),... 

The solvent sublation procedure of Wickbold [18] is another method that has been used for the analysis of LAS present in seawater [19,20], The solvent sublation technique (gaseous stripping into organic solvent, often ethyl acetate) has also been used to isolate and concentrate nonionic surfactants, e.g. AEs and APEO in aqueous samples [21,22], The co-extracted interferences can be eliminated by cation/anion ion-exchange and alumina chromatography [23,24]. 

ASTM D126 IP 107) that uses a modification of the standard wick-fed lamp. Many laboratories use rapid combustion techniques with an oxyhydrogen flame in a Wickbold or Martin-Floret burner (ASTM D2784 IP 243). 

Kravetz, L. Chung, H. Rapean, J. C. Guin, K. F. Shebs, W. T. Presented at American Oil Chemists Society 69th Annual Meeting, St. Louis, May 1978. Wickbold,R. VomWasser33,229(1966). 

IP LLE methods are generally employed for the extraction of LASs from river waters and the solvent sublation method of Wickbold is still used for their extraction from seawater [85]. SPE methods making use of C18 and C8 phases are largely employed [85]. The amount of sorbent is optimized as a function of the degree of pollution and the average composition of river waters [85]. The performances of C18 disks and C18 cartridges are compared [85]. 

Bock, K.J., and R. Wickbold. 1966. Effects of change to easily biodegradable detergents in a large scale sewage treatment plant and its effluents. Vom Wasser 33, 242-253. 

One of the oldest methods in the literature for the measurement of organic fluorine compounds is the Wickbold method [125], where organic fluorine is converted to hydrogen fluoride via combustion. The Wickbold method is useful for determining the total organic fluorine content of a sample, but is nonspecihc and does not provide information on individual fluorinated molecules. In addition, for samples containing PFCs, the combustion may lead to incomplete decomposition and subsequent underestimation of the total fluorine content of the sample [125]. 

Wickbold, R. Die photometrische trubunoptitration zur bestimmeng kleinster sulfatmengen. Agnew. Chem., 66 173 (1954). 

The Wickbold combustion technique is suitable for processing liquid combustible samples such as petroleum products, which are difficult to decompose by other techniques [178]. In the Wickbold combustion system, an oxygen-hydrogen flame is used for sample decomposition at high temperatures (2000 °C). Liquid samples are directly introduced to the flame, whereas solid samples require a preliminary... 

A Wickbold combustion apparatus (V5 Heraeous, Germany) is commercially available. 

Wickbold, R. Neue Schnellmethode zur Halogenbestimmung in Organischen Substanzen. Angew. Chem. 64, 133-135 (1952)... 

The lamp combustion method (ASTM D-1266, IP 107) and the Wickbold combustion method (IP 243) are used for the determination of sulfur in petroleum and as trace quantities of total sulfur in petroleum products and are related to various other methods (ASTM D-2384, ASTM D-2784, ASTM D-2785, ASTM D-4045)... 

Analytical methods are available in standard form for determining volatile sulfur content and certain specific corrosive sulfur compounds that are likely to be present. Volatile sulfur determination is made by a combustion procedure (ASTM D-126, IP 107) that uses a modification of the standard wick-fed lamp. Many laboratories use rapid combustion techniques with an oxy-hydrogen flame in a Wickbold or Martin-Floret burner (ASTM D-2784, IP 243). 

A more recent development is the Wickbold method (ASTM D-2785, IP 243). This is basically similar to the lamp method except that the sample is burned in an oxy-hydrogen burner to give much more rapid combustion. An alternative technique, which has the advantage of being nondestructive, is X-ray spectrography (ASTM D-2622). 

Flame Decomposition. Utilization of a petroleum sample as a fuel for combustion in a specially devised burner system, such as that described by Wickbold (6), can be an effective way to destroy large amounts of an organic matrix. The method is applicable to those elements which are either volatile or form volatile compounds and which can be trapped quantitatively in a suitable scrubber. This technique was used to prepare samples for cold vapor atomic absorption determination of mercury. Details are included in Chapter 12. 

Except neutron activation, methods which have been used to determine mercury in organic materials involve a matrix decomposition step prior to the actual measurement. Oxidative techniques involving various combinations of acids and salts have been widely used for matrix destruction (1, 2, 3, 4, 5), as have the Schoniger, Wickbold, and other bomb and tube combustion techniques (1, 6, 7, 8, 9,10). 

The Project investigated two methods for sample decomposition before mercury measurement. One involved acidic oxidation, and the other involved combustion in a Wickbold oxy-hydrogen burner (26). 

Wickbold Decomposition. The Wickbold decomposition apparatus is shown schematically in Figure 12.2. It consists of a sample reservoir, stainless steel burner, quartz combustion chamber, and an absorber con-... 

Application to Acidic Permanganate Absorber. In the Wickbold apparatus the mercury is collected in the acidic permanganate absorber. In this case, a solution of hydroxylamine must be added to the absorber prior to measurement to reduce all the manganese to the divalent state, in which form it does not interfere with the reduction of ionic mercury to elementary mercury by tin (II). 

Table 12.III. Recovery of Mercury by Wickbold Combustion Method...

Wickbold Decomposition—Cold-Vapor Atomic Absorption Method. 

Sample Added INAA Wet Oxidation CVAA Wickbold— CVAA... 

The acid decomposition procedure was developed using a recirculating cold-vapor atomic absorption technique for measurement. The Wickbold decomposition procedure used a flow-through cold-vapor atomic absorption measurement technique. Consequently, each measurement technique is presented with the decomposition procedure used in its development. However, since the two measurement techniques are comparable, either may be used after the alternate decomposition technique. 

Scope. This method is applicable to the determination of mercury in petroleum and petroleum products (except leaded gasoline) which can be burned in a Wickbold apparatus. The method is capable of measuring the amount of mercury in a sample down to the 5-ng/g level. The upper limit of the method as presented is determined by the linearity of the mercury calibration curve (Figure 1.2). Three to four samples can be analyzed conveniently at one time, and the average analysis time is about 2 hr. 

Outline of Method. A sample is weighed into a beaker, dissolved in benzene 2-propanol, and burned in an oxy-hydrogen flame using a Wickbold combustion apparatus. The combustion products are collected in a 5% sulfuric-nitric acid mixture containing potassium permanganate. Prior to measurement, trapped mercuric salts are reduced to elemental mercury with tin (II) chloride. The mercury is then swept out of solution and measured by cold-vapor atomic absorption spectroscopy. 

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