Chloroform test sample

Absorption of metallic acetylacetonates was carried out by immersing test papers in nonaqueous solutions of the iron (III) or copper (II) compound. In both cases, the solution concentration was 5 X 10-3 M. Iron(III) acetylacetonate was dissolved in acetone, and a mixture of acetone and chloroform (1 1) was used to dissolve copper(II) acetylacetonate. Test samples were immersed in metallic acetylacetonate solutions for 30 min and then were air dried. 

The same expression is obtained for the shear modulus G at small deformations under application of a shear stress oji. Conventional measurements of the cross-link density are, therefore, performed by defined sample deformation, for instance, in a rheometer during the vulcanization process of a test sample. The maximum rheometer moment for a given deformation amplitude is a direct measure of the cross-link density. Another, but invasive method for measuring cross-link densities in unfilled elastomer samples is by swelling in chloroform or toluene. In practice, spatial variations in cross-link density... 

Recrystallization. The crude product, 26.8 g, was dissolved in 200 ml chloroform. Dry hydrogen chloride gas was made to bubble through the resulting solution till such time when a small test sample (TS) of the solution gave a positive acid test to a wet pH indicator paper. The precipitate thus obtained was recovered by filtration rmder suction, washed with chloroform and dried under vacuum to obtain a crystalline product having mp 246°-247.5°C. 

In non-aqueous SEC, benzene, methanol, and acetone can be used as test samples with tetrahydrofuran or chloroform as the mobile phases and polystyrene gels as the column packing material. In aqueous SEC, ethylene glycol, sodium p-toluenesulfonate, glucose, and phenylalanine are employed, according to the type of column packing materials and the experimental conditions. 

The mycotoxins are extracted with a solvent that dissolves as much of the mycotoxin and as little of the other components of the test sample as possible. Numerous methods have been devised to determine the presence of the various mycotoxins. Some of these have been studied collaboratively for accuracy and precision. Other methods have been designed to screen for more than one mycotoxin simultaneously. Acetonitrile, chloroform, acetone, ethyl acetate, and methanol, or mixtures of these solvents with water are used as the extraction solvents. An acid is sometimes added to extract compounds containing carboxylic acids or acidic hydroxyl groups. In general, the more polar the mycotoxin, the more polar the extraction solvent should be. 

Figure 2 shows an acceptable pulse FT H NMR spectrum of a gas oil test sample dissolved in chloroform-d. 

Although simple analytical tests often provide the needed information regarding a water sample, such as the formation and presence of chloroform and other organohaUdes in drinking water, require some very speciali2ed methods of analysis. The separation of trace metals into total and uncomplexed species also requires special sample handling and analysis (12). 

One milliliter each of the borneol solution and the oxidizing solution are mixed in a test tube and briefly shaken. A TLC slide is spotted with the borneol solution, the camphor solution, and the ether layer of the reaction mixture. Spotting is done by means of a capillary melting point tube used as a dropper and filled with a 5 mm sample. The slide is developed in a wide-mouth jar containing a filter paper liner and a few milliliters of chloroform (Fig. A3.20). After development (the solvent front rises to within 1 cm of the top), the slide is removed, the solvent is allowed to evaporate, and the slide is placed in a covered wide-mouth jar containing a few crystals of iodine. The spots readily become visible and the progress of the reaction can easily be followed. With periodic shaking, the oxidation is complete in about 30 minutes. 

The solvents were evaporated in vacuo, and the residue was taken up in 80 ml of 3M hydrochloric acid. After addition of 220 ml of water, the insoluble material was filtered off, washed with 100 ml of water and then dried. The insoluble material weighed 9.5 g and was mainly unreacted bromo compound. The filtrate was reacted with 50 ml of 7 M NaOH, extracted three times with methylene chloride (50 m -t 2 x 25 ml portions), dried over potassium carbonate, and then evaporated. The yield of residue was 26.8 g which corresponds to 71.4% of the theoretical yield. This residue was a colorless solidifying oil and was dissolved in 200 ml chloroform. Hydrogen chloride was bubbled in until a sample of the solution tested acidic to wet pH indicator paper. A precipitate was obtained and recovered by filtration. The precipitate was washed with chloroform and dried. The melting point was determined to be from 246 Cto247.5°C. 

Various extraction methods for phenolic compounds in plant material have been published (Ayres and Loike, 1990 Arts and Hollman, 1998 Andreasen et ah, 2000 Fernandez et al., 2000). In this case phenolic compounds were an important part of the plant material and all the published methods were optimised to remove those analytes from the matrix. Our interest was to find the solvents to modily the taste, but not to extract the phenolic compounds of interest. In each test the technical treatment of the sample was similar. Extraction was carried out at room temperature (approximately 23 °C) for 30 minutes in a horizontal shaker with 200 rpm. Samples were weighed into extraction vials and solvent was added. The vials were closed with caps to minimise the evaporation of the extraction solvent. After 30 minutes the samples were filtered to separate the solvent from the solid. Filter papers were placed on aluminium foil and, after the solvent evaporahon, were removed. Extracted samples were dried at 100°C for 30 minutes to evaporate all the solvent traces. The solvents tested were chloroform, ethanol, diethylether, butanol, ethylacetate, heptane, n-hexane and cyclohexane and they were tested with different solvent/solid ratios. Methanol (MeOH) and acetonitrile (ACN) were not considered because of the high solubility of catechins and lignans to MeOH and ACN. The extracted phloem samples were tasted in the same way as the heated ones. Detailed results from each extraction experiment are presented in Table 14.2. 

Chlorofonn is too non-polar to dissolve the phenolic compounds under study, but it dissolves many of the monoterpenes, at least to some extent. Because the solubility of some monoterpenes into chloroform was low, different solvent/ solid ratios were tested. These were 50,20,10 and 5 1/kg of dry phloem. The extracts were bright yellow and the strongest colour was with the smallest solvent/solid ratio (51/kg). The colour of the solvent indicated that the solubility of the extractable compounds was not restricting the reaction even with the smallest solvent volume. The taste of the dry samples was evaluated by comparing them to the original phloem sample. The results showed that the mildest taste was in the phloem extracted with a solvent/solid ratio of 50 1/kg and 20 1/kg also had some effect on the taste. The taste of the chloroform-extracted phloem was stabile and it was the same after a week. 

Procedure If the fixed sample is studied, the cells are treated with tested allelochemical 10-5 - 10 4 M dissolved in organic solution (ethanol, chloroform, dimethylsulfoxide). But if the vital sample is needed, the solution is first diluted with water up to the ratio of organic solvent water, was more than 100. 

Obtain samples of the following 11 organic liquids contained in individual small dropper bottles n-hexane (or other alkane), acetonitrile, methylene chloride, acetone, toluene, methanol, diethyl ether, ethyl acetate, ethylbenzene, ethanol, and chloroform. Then label each of the test tubes from step 1 with the names, or an abbreviation of the names, of these liquids. 

Using numerical taxonomy it was found that the best separations were obtained by chloroform-methanol-(98-100 per cent) formic acid (44.1 3 2.35) and n-hexane-ethyl acetate-glacial acetic acid (31 14 5, v/v) as mobile phases. As the flavonoid profile of the propolis samples showed considerable differences, the method has been proposed for the authenticity test and traceability of various propolis products [141]. 

In the test method (ASTM D4930), a weighed dry representative coke sample 6.3 mm in maximum size is extracted using methylene chloride in a Soxhlet apparatus. The mass of the residue remaining after extraction and evaporation of the solvent is the mass of the dnst control material. This test method is limited to those materials that are solnble in a solvent (e.g., methylene chloride) that can be used in a Soxhlet extraction type of apparatns. Tolnene and methyl chloroform have also been found to give resnlts eqnal to those of methylene chloride. 

To date, laboratory sampling tests for acetone, methyl-chloroform, trichloroethylene and toluene have confirmed the Pro- G-BB Organic Vapor Air Monitoring Badge s ability to ... 

Porous silica is most widely used as adsorbent, but bonded phase materials with polar groups or crosslinked acrylonitrile39> have also been tested. Silica requires painstaking control of activity. In the separation of poly(styrene-co-methyl methacrylate) samples with dichloroethane—chloroform mixtures, clearer results were obtained with a silica column previously rinsed with methanol40. Continuously decreasing activity of silica columns was observed in the elution of poly(styrene-co-methyl acrylate) with CCU-methyl acetate mixtures38). 

For small sample sizes, a 1 1 ratio of filtrate to chloroform can be placed in a screw-cap test tube, mixed, and centrifuged to separate the phases. Rapid and clean phase separation is produced with this method. 

Method. To the dry sample residue in a 5-ml test-tube is added 0.5 ml of 0.1 M sodium carbonate. An equal volume of a solution of NBD-Cl (1% in IBMK) is then added carefully to the surface of the aqueous phase. The test-tube is loosely stoppered, heated at 80 °C for 30 min and then cooled. A 5-ml aliquot portion of the IBMK layer is used for TLC. The NBD-amine derivatives are separated with chloroform-tetrahydrofuran (49 1). The spots are observed visually at 365 nm. An aliquot portion of the organic layer may also be subjected to HPLC analysis using Zipax or a similar stationary phase and a 1% solution of tetrahydrofuran in hexane as the mobile phase. The separation of several NBD-amines by HPLC is shown in Fig. 4.68. 

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