The Shodex STANDARD S-Series (SL-105 Kit, SM-105 Kit, SH-75 Kit) is Polystyrene (n = 4 to 200,000) for SEC and it is easily soluble in tetrahydrofuran (THF), chloroform, toluene, and o-dichlorobenzene (ODCB).
For organic solvent SEC (GPC)
Less branched polystyrene with anionic polymerization
Chromatographic determinations of the molecular weight (MW) properties of polymers, either in organic or aqueous phase, rely on calibration with Standards of highly characterized MWs for accurate results. Expressed simply, Size Exclusion (or Gel Permeation) Chromatography enables polymer molecules of different sizes in solution to be separated from one another, such that the large molecules elute first and small molecules elute last. Since the molecular size in solution (hydrodynamic volume) is related to MW, a picture of the entire MW Distribution (MWD) may be obtained quickly and simply. This is in great contrast to the “absolute” techniques of MW determination which frequently could take half a day per sample to define a single average MW.
Polymer Standards are thus an integral part of any quantitative Size Exclusion Chromatography. These Standards need to be highly characterized by as many absolute and chromatographic techniques as possible to define the MW averages and MWD. The closer the value of the MWD is to unity, the sharper will be the polymer peak and the better the material will be for a Calibration Standard.
Note: Molecular weights (Mp, Mw/Mn) of a standard kit or each single type may vary depending on production lots. Always refer to the inspection certificate.
Molecular weights (Mp) Range*
0.5 g x 10 kinds
580 − 25,000
0.5 g x 10 kinds
1,000 − 2,500,000
0.5 g x 7 kinds
600,000 − 7,000,000
Safety data sheet
Preparation of solutions
It is recommended as a general principle that the polymer concentration in solution and the injection volume both be kept as low as possible concurrent with the sensitivity of the system to reduce as much as possible deleterious effects such as column broadening and viscous trapping. This becomes even more critical when very high molecular weights are involved. Solutions should be made up at room temperature only.
Handling of MWs above 1,000,000 should avoid degradation of polymer when making up a solution. It is recommended that gentle agitation by hand is used at intervals throughout a 24 hr period, by which time complete dissolution will normally occur.
Polystyrene Standards are stable materials themselves, but these are degraded by air, sunlight and heat. So that Polystyrene Standards should be stored at room temperature of 20 to 25°C, and in the dark place. They should not be stored in direct sunlight or in wide temperature change.