Method Micro

Conradson carbon NFT60-116 ISO 6615 ASTM D 189 ASTM D 4530 ISO 10370 Weighing after combustion then pyrolysis Micro method... 

Determination of Melting-points. The determination of the melting-point, as described on pp. 2-4, is of course in itself a micro-method. Even so, when working on a very small scale it is advantageous to use either ... 

The comparatively wide prevalence of micro-methods of quantitative organic analysis, applied more particularly to the estimation of the constituent elements in an organic compound, may cause the advisability of including the macro-methods in Part IV to be questioned. Quite apart, however, from the fact that the micro-methods still find no place in many laboratories, we consider that thorough practice in the macro-methods of quantitative analysis to be not only an excellent introduction to the micro-methods themselves, but also a valuable training in exact manipulation generally. 

When only minute quantities of liquid are available, either of two micro methods for the determination of the boiling point may be used. 

The hardness of carbides can only be deterrnined by micro methods because of britdeness, the usual macro tests caimot be used. Neither can the extremely high melting points of the carbides be readily deterrnined by the usual methods. In the so-called Priani hole method, a small hoUow rod is placed between two electrodes and heated by direct current until a Hquid drop appears in the cavity. The temperature is determined pyrometricaHy. When high temperature tungsten tube furnaces are used, the melting point can readily be estimated by the Seger-type cone method. The sample may also be fused in a KroU arc furnace and the solidification temperature determined. 

N. D. Cheronis andT. S. Ma, Organic Eunctional Group Hnaljsis bj Micro and Semi-micro Methods, Interscience Pubhshers, Inc., New York, 1964, pp. 493-496. 

The Micro-method uses an analytical instrument to measure Conradson carbon in a small automated set. The Micro-method (ASTM D4530) gives test results that are equivalent to the Conradson carbon residue test (D189). The purpose of this test is to provide some indication of relative coke forming tendency of such mat al. 

Before discussing these most commonly applied tests in detail, certain general principles should be presented. Converting a macro-method to a micro-method sometimes involves no more effort than decreasing all the volumes used in the procedure. This general procedure is well known to clinical chemists. A typical example would be the Folin method for doing sugar analysis, where a final volume of 25 ml was obtained. 

Natelson, S. Routine use of ultra-micro methods in the clinical laboratory. Am. J. Clin. Path. (1951),... 

Soldin, S.J. and Hill, J.G., A rapid micro method for measuring theophylline in serum by reversed phase high performance liquid chromatography, Clin. Biochem., 10,74,1977. 

Rigaud, J. et ah. Micro method for the identification of proanthocyanidin using thiolysis monitored by high-performance liquid chromatography. J. Chromatogr. 540, 401, 1991. 

G. HIGH CARBON VALUES FOR MICRO METHOD, CONRADSON, AND RAMSBOTTOM CARBON NUMBER DETERMINATIONS... 

The following information can be obtained from Micro Method, Conradson and Ramsbottom carbon values ... 

Hata R, Nagai Y (1972) A rapid and micro method for separation of acidic glycosaminoglycans by two-dimensional electrophoresis. Anal Biochem 45 462-468... 

Czubayko F, Beumers B, Lammsfuss S, Lutjohann D, von Bergmann (1991) A simplified micro-method for quantification of fecal excretion of neutral and acidic sterols for outpatient studies in humans. J Lipid Res 32 1861-1867... 

Complexometric titration with EDTA is the usual winery procedure for determining calcium (4, 6, 22, 113), but atomic absorption spectrophotometry (51,53,112) and flame photometry and a rapid micro method based on oxalate precipitation (114) have been used successfully. 

Lawrence and Sanderson proposed another micro-method for measuring chymosin and other proteolytic enzymes. Measurement of concentration was based on the rate of radial diffusion of the enzyme through a thin layer of caseinate-agar gel. The limit of diffusion was marked by a zone of precipitated casein (Emstrom and Wong 1974). Holmes et al (1977) developed a microdiffusion assay for residual proteolytic enzymes in curd and whey that is more sensitive than the method of Lawrence and Sanderson or the clotting-time assay of Reyes (1971). 

It has been found that in spectral analytical investigation the interrupted and flaming arc methods are respectively 100 and 10 times more sensitive than the condensed spark method.6 As little as 2 x 10 s mg. of arsenic can thus be detected in solid alloy electrodes and, in solutions free from heavy metals, 0-01 per cent, of arsenic can be detected.7 Micro-methods for the spectrographie determination of small amounts of arsenic have been described.8... 

DERIVATIZATION OF THE ION-EXCHANGE CLEANED PHYSIOLOGICAL FLUID. Micro Method (2-200 pg total)... 

In the micro method of combustion, substances containing any of these elements (N, S and halogen) can be combusted in one tube by the use of the so-called Universal Filling (see section on Micro-analysis, p. 453). 

Whilst the fundamental principles of combustion are common to both macro and micro methods, the actual conditions and mode of operation are markedly different. In the micro method the importance of absolute cleanliness and neatness of operation cannot be overstressed. 

Whilst the ultimate ideal in organic analysis is the general adoption of micro methods, it has to be appreciated that such ideals cannot always... 

Notes. (1) The success of the dry-column technique for the resolution of mixtures is completely dependent on the use of the correct activity grade of adsorbent. It should not be assumed that the grade purchased is activity I, to which the appropriate amount of water could be added (see earlier). It is therefore essential to determine the activity by the use of the method previously described, or by using the elegant micro-method described by Loev and Goodman in their definitive paper. 

Cheronis, N. D. Micro- and Semi-micro Methods. New York Interscience Publ. 1954. 

Alimarin, J. P., and M. N. Petrikova The Ultra-Micro Method of Chemical Analysis. II. The Electrolytic Separation. Zh. Analit. Khim. (Russ.) 5, 11 (1953) J. Anal. Chem. USSR (Engl. Transl.) 8, 11 (1953). 

Steinwandter, H. (1992). Contributions to the ethyl acetate application in residue analysis. I. Micro method for extracting atrazine residues from soil samples. J. Anal. Chem., 343(7) 604-606. 

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