Cellulose colorimetry

Methods of Extraction and Analyses. Chloropyrifos, Ronnel, chlorpropham and 2,4,5-T were extracted from the cloth or the cellulose pad with hexane. Pentachlorophenol residues were extracted with benzene. Pentachlorophenol was methylated with diazomethane prior to determination by gas chromatography while the other compounds were determined dirgctly. Dinoseb, on the other hand was extracted with chloroform and partitioned into 2% Na2 Co3 solution. The yellow extract was analyzed colorimetri-cally using the method of Potter (14). 

S-anions Cellulose ring-colorimetry Different spray reagents 0.2-1 Mg 245)... 

The Englyst procedure uses enzymatic and chemical methods to measure NSP. (For detailed working protocols, see Further Reading.) All starch is hydrolyzed enzymatically and NSP are measured as the sum of the constituent sugars released by acid hydrolysis. The sugars may be measured by GC or by HPLC to obtain values for individual monosaccharides, or a single value for total sugars may be obtained by colorimetry. Values may be obtained for total, soluble, and insoluble NSP, and a small modification allows cellulose to be measured separately. 

The shape and size of the spot produced on chromatograms are decisively influenced by the amount of solute, the volume of the solution applied, the diameter of the spot at the start, and series of other factors. In an attempt to standardize the quantification in TLC, Mohammad and Tiwari (141) and 0. Shadrin et al. (143) have established a linear relationship between the size of the spot and the amount of inorganic anions. A representative plot is given (Fig. 6). A. Timeibaev et al. (164) have determined Ti in sulfite-cellulose liquor and high speed steel by visual colorimetry or by planimetry using a calibration graph. 

Fig. VII-7. The chromatographic fractionation of TNP-ated clupeine into TNP-clupeine YI, TNP-clupeine Z and free clupeine YII. TNP-ated whole clupeine (8.1 mg) was added on a column of CM-cellulose (0.9 x 89 cm). It was developed with 0.1 M acetate buffer, pH 3.51, containing 0.6 M sodium chloride. The flow rate was 2.3 ml per fraction per 10 min at room temperature. The column was covered with aluminium foil to protect the TNP-derivatives from photodecomposition. The effluent from the column was analyzed by Sakaguchi colorimetry (ODsoo mix) and spectrophotometry at 340 mfi.-OD500 m x Sakaguchi color value.

Fig. VIII-6. Chromatographic separation and identification of peptides in a thermolysin digest of TNP-clupeine YI. The digestion mixture (from 2.27 p,moles of TNP-clupeine YI) was applied to a column (0.9 cm x 150 cm) of CM-cellulose. Peptides were first eluted with the starting buffer (0.1 M acetate buffer, pH 6.0 tubes 1—80), then an exponential gradient elution was applied (81—514). The mixing chamber contained 1000 ml of starting buffer and to the reservoir 0.1 M acetate buffer (pH 6.5) containing 1.0 M NaCl was added. The peptides remaining on the column were eluted with 0.1 M HCl. The flow rate of the effluent was 3.89 ml/tube/18 min. The effluent was analyzed by Sakaguchi colorimetry and spectrophotometry at 340 mp. The color yield (Sakaguchi reaction) was 101 % (tubes 1 to 555) [from Ando and Suzuki, 1967 Suzuki and Ando 1972 (2)]...

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