A method was validated intralaboratory to analyze low molecular weight P(D,L)LA (polylactic acid) in tetrahydrofuran (THF) with respect to the number average molar mass (Mn) and weight average molar mass (Mw). For this purpose, a KNAUER HPLC system was used in combination with a linear GPC column. The obtained molar masses were compared with the values of the absolute methods and any deviations were discussed. The method was validated with respect to its repeatability and robustness to changes in flow rate, temperature, injection volume and sample concentration.
14-point PS universal calibration in THF
Mn (dots) and Mw (squares) values at 0.3-, 0.5-, 1.0-, 2.0-, and 3.0 mg/ml sample concentration. Triple determination with relative standard deviation
| Method | HPLC |
|---|---|
| Mode | GPC |
| Substances | polylactide, polylactic acid |
| Key words | PLA, polylactide, polylactic acid, GPC, SEC, polymer, biopolymers, bioplastic, biodegradable, universal calibration, PS, polystyrene, PMMA, green SEC, green GPC, biobased plastic, validation |
| Version | Version 1/ 11/2021 |
Determining molecular weights of polylactic acids
AZURA® Pump P 6.1L (HPG), without degasser, with 10 ml normal phase pump head (stainless steel and mixer (400 µl)
Article No.: APH38ED
Show product
AZURA® Autosampler AS 6.1L analytical HPLC autosampler, 700 bar
Article No.: AAA00AA
Show product
AZURA® RID 2.1L analytical refractive index detector with flow cell
Article No.: ADD31
Show product
Column thermostat AZURA CT 2.1 for constant temperatures and reproducible results
Article No.: ATC00
Show product
GPC in separation range of 500 Da-1.5 MioDa (BPT: Broad Poredistribution Technology)
Article No.: 05GW470ABJ
Show product
GPC in separation range of 500 Da-1.5 MioDa (BPT: Broad Poredistribution Technology)
Article No.: 30GW470ABJ
Show product
ClarityChrom® single instrument license for one time base
Article No.: A1670
Show product
ClarityChrom® option for GPC data processing
Article No.: A1678
Show productWe are happy to help you
