Comparison of Ultraviolet Absorption and Chlorine Analysis Methods for Composition of Butadiene-p-Chlorostyrene Copolymers

1947 ◽  
Vol 20 (1) ◽  
pp. 313-314 ◽  
Author(s):  
E. J. Meehan ◽  
T. D. Parks ◽  
H. A. Laitinen
Keyword(s):  
Extinction Coefficient ◽  
Spectrophotometric Method ◽  
Wave Length ◽  
Chloride Ion ◽  
Amperometric Titration ◽  
Specific Extinction Coefficient ◽  
Styrene Copolymers ◽  
Composition Determination ◽  
Butadiene Styrene

Abstract The percentage of chlorine in a copolymer containing chlorostyrene can be determined by amperometric titration of the chloride ion present after sodium fusion of the polymer. Since the percentage of chlorine is proportional to the percentage of chlorostyrene, the composition of a butadiene—chlorostyrene copolymer may be determined directly. This absolute method of composition determination affords a means of checking the ultraviolet spectrophotometric method which has been proposed for the determination of the composition of butadiene—styrene copolymers. In the application of the spectrophotometric method it is assumed that the specific extinction coefficient of the copolymer varies linearly with the percentage of styrene between the values of the same wave length for polybutadiene and polystyrene. The spectrophotometric measurements are made at 260.0 mµ or at 269.5 mµ for copolymers of butadiene with styrene or with p-chlorostyrene, respectively.

Spectrophotometric Determination of the Styrene Content of Butadiene-Styrene Copolymers

1946 ◽  
Vol 19 (4) ◽  
pp. 1077-1084 ◽  
Author(s):  
E. J. Meehan
Keyword(s):  
Molecular Weight ◽  
Spectrophotometric Determination ◽  
Extinction Coefficient ◽  
Ultraviolet Spectrophotometry ◽  
Relative Precision ◽  
Specific Extinction Coefficient ◽  
Styrene Copolymers ◽  
Styrene Content ◽  
Butadiene Styrene

Abstract The ultraviolet absorption of polystyrene, with maximum absorption at 262 mµ, is due to the presence of phenyl residues in the polymer. The specific extinction coefficient is constant, i.e., independent of the molecular weight of the polymer. This shows that the extinction of the phenyl residues is additive. On the basis of this fact, it is shown that the styrene content of a butadiene-styrene copolymer (such as GR-S rubber) can be determined by ultraviolet spectrophotometry. The relative precision of the determination is about 1 per cent, the probable relative accuracy is about 3 per cent.

scholarly journals A spectrophotometric method for determination of fluorophore-to-protein ratios in conjugates of the blue fluorophore 7-amino-4-methylcoumarin-3-acetic acid (AMCA)

1990 ◽  
Vol 38 (1) ◽  
pp. 87-94 ◽  
Author(s):  
M W Wessendorf ◽  
S J Tallaksen-Greene ◽  
R M Wohlhueter
Keyword(s):  
Acetic Acid ◽  
Optical Density ◽  
Extinction Coefficient ◽  
Spectrophotometric Method ◽  
Extinction Coefficients ◽  
Beer's Law ◽  
Beer’S Law ◽  
The Given

7-Amino-4-methylcoumarin-3-acetic acid (AMCA) has been found to be a useful fluorophore for immunofluorescence. The present study describes a spectrophotometric method for determining the ratio of moles AMCA to moles protein (or the f/p ratio) in an AMCA-conjugated IgG. The concentration of a substance absorbing light can be determined spectrophotometrically using Beer's Law: Absorbance = Concentration x Extinction coefficient. From Beer's law, one can derive the following formula for determining the f/p ratio of AMCA-IgG conjugates: f/p = (epsilon 280IgG).A350 - (epsilon 350IgG).A280/(epsilon 350AMCA).A280 - (epsilon 280AMCA).A350 where A is the optical density of the conjugate at the given wavelength and epsilon is the extinction coefficient of a substance at the wavelength specified. Using conjugates of model proteins, it was found that the extinction coefficients of the AMCA moiety of AMCA-conjugated protein were 1.90 x 10(4) at 350 nm and 8.29 x 10(3) at 280 nm. Similarly, it was found that the extinction coefficients of swine IgG were 1.56 x 10(3) at 350 nm and 1.26 x 10(5) at 280 nm. Thus, for AMCA-conjugated swine IgG: f/p = (1.26 x 10(5)).A350 - (1.56 x 10(3)).A280/(1.47 x 10(4)).A280 - (6.42 x 10(3)).A350 [corrected]. Based on this formula, the f/p ratios of some AMCA-IgG conjugates useful for immunohistochemistry have been found to range between 6 and 24.

scholarly journals Decolorization of colored boiler water and determination of chloride ion by spectrophotometric method.

1987 ◽  
Vol 36 (5) ◽  
pp. T55-T57
Author(s):  
Setsuko KUDO ◽  
Choetsu HOSONO ◽  
Nobuo SUZUKI
Keyword(s):  
Spectrophotometric Method ◽  
Chloride Ion ◽  
Boiler Water

FURTHER DEVELOPMENTS IN THE VISTEX METHOD FOR THE DETERMINATION OF THE INTRINSIC VISCOSITY OF HIGH POLYMERS

1949 ◽  
Vol 27b (7) ◽  
pp. 666-681 ◽  
Author(s):  
D. A. Henderson ◽  
N. R. Legge
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Average Molecular Weight ◽  
Solvent Mixture ◽  
Gel Point ◽  
Styrene Copolymers ◽  
A Value ◽  
Pure Solvent ◽  
Butadiene Styrene

The intrinsic "vistex" viscosities of several series of butadiene–styrene copolymers of varying conversion and average molecular weight, dissolved directly from the latex in the vistex solvent mixture (toluene–isopropanol, 80/20 by volume), have been investigated and compared with the intrinsic viscosities of the corresponding coagulated, dried polymers dissolved in toluene. The intrinsic viscosity in toluene, [η]T, is related to the intrinsic vistex viscosity, [η]V, in toluene–isopropanol by the equation:—[Formula: see text]Hence, viscosity average molecular weight may be calculated from vistex measurements.A further development of the method has shown that, once the latex is dissolved in the vistex solvent, the solution may be diluted, within certain denned limits, by the addition of pure solvent (toluene) to obtain the several levels of concentration of polymer required for the determination of intrinsic viscosity. It is then possible, by extrapolation to zero concentration of polymer, to obtain a value for the intrinsic viscosity that is equal to the conventional intrinsic viscosity of the polymer in pure solvent after coagulation and drying under very mild conditions. The viscosity characteristics of butadiene–styrene copolymers of varying conversion appear to be represented, at conversions below the gel point, by the equation,[Formula: see text]where β′ and n are constants of the order of 0.25 and 1 for solutions in toluene and 0.1 and 2.5 respectively for vistex solutions. Distinct changes in β and/or n have been found at conversions in the region of and beyond the gel point.

Direct Spectrophotometry of Total Serum Bilirubin in the Newborn

1960 ◽  
Vol 6 (5) ◽  
pp. 421-428 ◽  
Author(s):  
Samuel Meites ◽  
Cecelia K Hogg
Keyword(s):  
Spectrophotometric Method ◽  
Phosphate Buffer ◽  
Serum Bilirubin ◽  
Wave Length ◽  
Total Serum Bilirubin ◽  
Total Serum ◽  
Direct Spectrophotometry ◽  
Similar Equation

Abstract A simple, rapid direct spectrophotometric method for the determination of total serum bilirubin on a micro basis, with a 1:21 dilution of serum in phosphate buffer, is presented for use with the Junior Coleman spectrophotometer. The formula, mg./100 ml. bilirubin = 50 A455 - 119 A575, is applied, where A represents the absorbancy at the wave length specified. The method for obtaining this or a similar equation is presented. The spectrophotometric method, when applied to sera obtained from newborns, gives apparently reliable results in the presence or absence of hemolysis. An evaluation of the method and its limitations is presented.

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