Calibration of light‐scattering instruments: A critical survey

Abstract

A survey of the literature on the calibration of light scattering instruments has been made, including an extensive bibliography. The values of the Rayleigh ratio R90 and depolarization ρμ for benzene, toluene, carbon tetrachloride, and carbon disulfide and the excess turbidity of Cornell polystyrene and D.C./P.J.3 polystyrene (0.5% solutions in toluene) were tabulated for two wavelengths (4358 and 5461 A.). Examination of these results showed a larger variation in reported values than is generally assumed acceptable (only so‐called “high” values have been considered). No correlation was found with the various standards used for the original calibration. Some aspects of the most usual methods of calibration are discussed and arguments are considered which would favor those values of R90 (or excess turbidity) that are at the lower limits of the range reported (but still in the region of “high” values). The difficulty of using Einstein's equation in determining the exact values of R90 is pointed out.

Reexamining protein–protein and protein–solvent interactions from Kirkwood-Buff analysis of light scattering in multi-component solutions

“…62 "High" R 90 values correspond to those values (methods) which return the average molecular weight of a standard polymer when they are used in Eq. (29) for a dilute solution of the same polymer, [63][64][65][66][67][68] whereas "low" values do not correlate well with the expected M 2 values for standardpolymer solutions.…”

Dilute Solution of Bisphenol A Polycarbonate

“…These Pu values are in agreement with the reported values. 13 Measurements on Polymer Solutions. Measurements on polycarbonate solutions were made at 25°C in the angular range from 30 to 150°, using, in most cases, vertically polarized incident light of the wavelength 436 nm.…”

Stiff Chain Behavior of Poly(phthaloyl-trans-2,5-dimethyIpiperazine) in Dilute Solution

“…Table V summarizes the values of s0 and ks for all the fractions that were subjected to sedimentation velocity experiments. These data for s0 are quite closely represented by So= 1.29 X 10-15 Mw 0 ' 38 (NMP) ( 6) S 0 =2.9 7 X 10-ts Mw 0 ' 38 (DMA) ( 7) where s0 is measured in seconds. Again it should be noted that the exponents to M.,, for NMP and DMA solutions are equal.…”

“…6 The depolarization, Pu, of benzene was found at be 0.429 at 436 nm, in good agreement with the reported values. 7 Polymer solutions and solvents were made free from dust and microgels by centrifugation at 4.9 x 10 4 gravities for 2 hr in a Sorvall Type RC2-B centrifuge and then directly placed in the light-scattering cell with carefully cleaned pipettes. No filtering was made.…”

“…The data obtained for z-average mean-square radii of gyration (S2)z, intrinsic viscosities [7)], and sedimentation coefficients so exhibited features predictable for stiff or semiflexible chains. Thus an attempt was made to analyze the data by combination of the Yamakawa-Fujii theory for intrinsic viscosity and the Benoit-Doty expression for mean-square radius of gyration of unperturbed wormlike chains with a reasonable assumption for the partial specific volume.…”