Standards Sorted by Type

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Molecular Weight Standards, GPC/SEC Calibration Kits and Validation Standards

PSS supplies certified standards that meet the requirements of DIN 55672 and ISO/EN 13885. All reference materials are characterized with GPC/SEC to obtain molecular weight values. These values are subsequently confirmed by alternative methods such as Laser Light Scattering, Viscometry, MALDI-ToF, VPO and NMR.

Each product comes with a Certificate of Analysis, which provides the characterization information, the testing parameters, the molecular weight values (M_n, M_w, M_p, PDI) and the chromatogram. Calibration kits include a calibration report.

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Protein

Order No.	Details	Nominal MW	Description	PDI	Packsize
PSS-prokit			Kit Protein, 10 x 0.1 g, M = 243 - 670 000 Da
PSS-prokitr1			ReadyCal-Kit Protein, 3 x 5 Vials-1.5ml, Mp = 243 - 670 000 Da

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Poly(ethylene terephthalate)

Order No.	Nominal MW	Description	PDI	Packsize
PSS-PET3.5K	3500	Poly(ethylene terephthalate)	<2,10	250,00
PSS-PET10K	10000	Poly(ethylene terephthalate)	<2,10	250,00
PSS-PET18K	18000	Poly(ethylene terephthalate)	<2,10	250,00
PSS-PET25K	25000	Poly(ethylene terephthalate)	<2,10	250,00
PSS-PET35K	35000	Poly(ethylene terephthalate)	<2,10	250,00
PSS-PET40K	40000	Poly(ethylene terephthalate)	<2,10	250,00
PSS-PET50K	50000	Poly(ethylene terephthalate)	<2,10	250,00
PSS-PET75K	75000	Poly(ethylene terephthalate)	<2,10	250,00
PSS-PET120K	120000	Poly(ethylene terephthalate)	<2,10	250,00

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Random copolymers

Order No.	Nominal MW	Description	PDI	Packsize
PSS-PSMM100K	103000	Poly(styrene-methyl methacrylate) 20/80	1,27	1000,00
PSS-PSMM51K	50700	Poly(styrene-methyl methacrylate) 83/17	1,49	1000,00
PSS-PSMM133K	133000	Poly(styrene-methyl methacrylate) 10/90	1,57	1000,00
PSS-PSMM87K	87700	Poly(styrene-methyl methacrylate) 51/49	1,63	1000,00
PSS-PSMM86K	85800	Poly(styrene-methyl methacrylate) 45/55	1,91	1000,00

Polydispersity Index, PDI

The Polydispersity Index, PDI, is a measure of the width of the molar mass distribution. It is defined as ratio of the weight average molar mass M_w and the number average molar mass M_n, PDI =M_w/M_n.

PDI is 1 for monodisperse substances (no molar mass distribution), it is larger than 1 for the vast majority of all macromolecules. The PDI depends on the polymerization technique applied to produce the material. In praxis the PDI can be very large up to values of 100 and above. Narrow PDIs can only be obtained using controlled/living polymerization techniques.

Please refer to the literature section to learn more.

Narrow Standards
Broad Standards

Narrow polymer standards are made by controlled/living polymerization techniques (living anionic/cationic, ATRP, RAFT, etc.) or by fractionation of very broad standards.

All narrow standards have small polydispersity indices and exhibit a sharp and slim chromatographic profile.

The M_p value (molar mass at the peak maximum) is well defined and independent on the column resolution. As M_p is the only clearly defined point in the chromatogram this value is used to establish GPC/SEC calibration curves.

Standards with a narrow molar mass distribution are used:

to construct a GPC/SEC calibration curve using the provided M_p values
for the validation of a chromatographic system
for the determining of physical constants

Broad reference materials are made by radical polymerization, polycondensation or coordinative polymerization (polyolefins).

The PDI of broad standards is usually > 1.5. For broad standards the M_p value is a function of the column resolution. Molar mass values provided for broad standards are thus only the average molar masses M_w and M_n.

Modern GPC/SEC software packages allow for the construction of a calibration curve by the use of M_w, M_n or the intrinsic viscosity [η] of broad standards.

Standards with a broad molar mass distribution are used:

to validate a chromatographic system
to determine physical constants such as the Mark-Houwink constants K and ∝
to construct a calibration curve using broad calibration options
to test for porosity mismatch