Sulfuric acid test

Preparation of the alcohol insoluble solids (AIS) The content of the can was drained and the carrot cubes were immediately frozen in hquid nitrogen, freeze-dried and milled. Carrot powder (ca. 10 g) was mixed with 200 ml 80% ethanol previously heated to 60°C. After filtration the residue was extracted with ethanol until the filtrate was colorless (5 times) and gave negative reaction with phenol-sulfuric acid test (Dubois et al., 1956). 

Table III gives a survey of the essential characteristics of the alcohols. It is remarkable that, despite the poor color value of the sulfuric acid test, esters can be obtained from the two hexanols with color values falling within the range of the platinum cobalt scale from 35 to 50.

Total Carbohydrates. The results of the phenol-sulfuric acid tests for total carbohydrates are listed in Table 1. The Lower and Middle Ordovician dolomites and limestones of this area did not yield detectable total carbohydrates, either because they are absent or because of metamorphic degradation. Palacas (5) and Palacas, Swain, and Smith (6), on the other hand, found traces of glucose and other sugars in Lower and Middle Ordovician rocks of Franklin County, Pa. southeast of the Mt. Union area. It appears that the early and medial Ordovician seas of the Mt. Union area may neither have been receiving much carbohydrate material from the lands nor was much being contributed by organisms to the bottom sediments. 

P. K. Stumpf, J. Biol. Chem., 169, 367 (1947). The Stumpf test is a quantitative application of the Dische cysteine-sulfuric acid test for estimation of deoxyribonucleic acid. 

Gel filtration of the hemicellulose was done on a G-50 Sephadex column with water as eluent by the National Food Research Institute of the CSIR. Neutralized samples were applied to the column and fractions (6 mL) collected, of which 1-mL aliquots were assayed by the phenol-sulfuric acid test ( ). Approximate calibration (D.P. versus elution volume on the G-50 column) was done by total carbohydrate and reducing sugar end group analysis (0) using enzymatically debranched starch as reference material. 

Figure 3 shows a plot of olefin conversions after equilibrium had been obtained versus A/0 ratios in the feed. The conversion results were essentially identical for all n-butenes and for all sulfuric acids tested. More than 10-30% excess sulfuric acid was needed to produce butyl sulfate (and also to cause olefin isomerization). 

The electrolyte composition was 0.24 M copper sulfate for the second part of the experiments, we added sulfuric acid. Tests were performed with 0.5-1.5 M of sulfuric acid obtaining the same type of morphology. The solutions were deaerated with bubbling nitrogen before experiments. The depositions were performed at ambient temperature without stirring. The rest of the procedure was similar to that used for Zn electrodeposition, with the necessary modifications. 

Specific gravity at 20/20 C Specific heat of liquid at 20"C Sulfuric acid test (Pt-Co) Surface tension at 20 C Suspended matter Toxicity... 

Purity, as decanol Refractive index at 20 C, Solubility in water at Z0 C Solubility of water in at 20 C Specific gravity at 20/20 Sulfuric acid test (Pt>Co scale) Suspended matter Vapor pressure at 20 C Viscosity at 20 C Water content Weight per gallon at 20 C... 

Strontium Selenite. A solution of 77 g. of sublimed selenium(IV) oxide in 154 ml. of distilled water is added to 500 ml. of pure strontium nitrate solution prepared as previously described. The solution is heated to boiling and fresh ammonium hydroxide solution is added until no further precipitation of strontium selenite occurs. The precipitate is drained and washed six times with 300-mI. portions of hot distilled water. The nitrate content should be less than 5 parts per million as determined by the diphenylamine-sulfuric acid test. The strontium selenite is dried at 200° for several hours. The yield is about 125 g. 

Microchemical testing is not only based on dissolution of binders but also on pigment and binder color reactions with oxidizing, dehydrating, or reducing agents. These tests are destructive diphenyla-mine (in concentrated sulfuric acid and glacial acetic acid) and LeRosen (formaldehyde in concentrated sulfuric acid) tests are typically used. 

FIG. 10—Apparatus for ferric sulfate-sulfuric acid test. 

It was known that alloy C (Table 1) could also become susceptible to intergranular attack as a result of exposure to a range of elevated temperatures. However, there was no reliable quantitative method available for detecting this condition until the publication in 1963 [24] of the results shown in Fig. 18. To demonstrate the applicability of the ferric sulfate-50 % sulfuric acid test, specimens were heat-treated for 1 h at temperatures between 900 and 2450°F (482-1343 C), and tested for 24 h. (This is much shorter than the 120-h period used for Typ e 304 because of the 2 % lower chromium content and the 16 % molybdenum in alloy C.) It was found in the ferric sulfate test that there are two maxima in corrosion rates one at 1300 F (704°C), which is... 

FIG. 19—Effect of carbon content in Ni-Cr-Mo alloys on corrosion in the ferric sulfate-50 % sulfuric acid test [25]. ( NACE International. All Rights Reserved by NACE reprinted with permission.)... 

FIG. 21—Intergranular attack on weldmant In ferritic stainless steel caused by high nitrogen content (5x). Autogenous weld In 28.5 %Cr<4.2 %Mo alloy with 22 ppm carbon and 388 ppm nitrogen after exposure In ferric sulfate-50 % sulfuric acid test. 

The accelerated Strauss test, ASTM A 262 Practice E (copper-copper sulfate-16 % sulfuric acid test), is also a popular quality control test because it is brief (typically 24 h) and includes an acceptance criterion. After exposure, specimens are bent to expose intergranular attack. Material with attack fails, while unattacked material passes. Experience is important in specimen evaluation to separate cracks" due to attacked grain boundaries from mechanical cracks that may have occurred in bending. Different laboratories have obtained varying results upon examination of the same set of sjjecimens [/2]. 

Procedure. A drop of the weak nitric or sulfuric acid test solution (the acidity should not be greater than 0.1 N) is mixed on a spot plate with a drop of reagent solution. According to the amount of mercury, a violet precipitate or pink color is formed. The reagent itself is colorless or faintly yellow in acid solution. 

The base solution for all tests was 0.5 M of sulfuric acid. Test tempreratures were ambient temperature ( 25°C). Test solutions bearing chloride ions were with 0.25, 0.50, and 1.00 M sodium chloride in the base solution. To avoid the dissolved oxygen (aeration) affecting the test solutions, deaeration was simultaneously made by a nitrogen gas flow of 120 ml/min in the test solution. The effect of temprerature on polarization was examined imder thermostatic control at an interval of 15°C in the temprerature range of 20°C - 65°C. 

A copolymer consisting of monomer 5f (2 mole%) and acrylic acid could be readily detected down to a concentration of 10 ppm using the phenol-sulfuric acid test. In a control experiment, unmodified poly(acrylic acid) gave a negative phenol-sulfiiric acid test. The loss of sensitivity of the method on going from the monomer to the copolymer is the result of dilution of the saccharide moiety with acrylic acid in the copolymer. 

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