Analysis of linear and cyclic oligomers in polyamide-6 without sample preparation by liquid chromatography using the sandwich injection method. II. Methods of detection and quantification and overall long-term performance.
By separating the first six linear and cyclic oligomers of polyamide-6 on a reversed-phase high-performance liquid chromatographic system after sandwich injection, quantitative determination of these oligomers becomes feasible. Low-wavelength UV detection of the different oligomers and selective post-column reaction detection of the linear oligomers with o-phthalic dicarboxaldehyde (OPA) and 3-mercaptopropionic acid (3-MPA) are discussed. A general methodology for quantification of oligomers in polymers was developed. It is demonstrated that the empirically determined group-equivalent absorption coefficients and quench factors are a convenient way of quantifying linear and cyclic oligomers of nylon-6. The overall long-term performance of the method was studied by monitoring a reference sample and the calibration factors of the linear and cyclic oligomers.
Mengerink
Y
Y
MI&Q, DSM Research, Geleen, The Netherlands. ynze.mengerink@dsm-group.com
Peters
R
R
Kerkhoff
M
M
Hellenbrand
J
J
Omloo
H
H
Andrien
J
J
Vestjens
M
M
van der Wal
S
S
D002209:Caprolactam / Q000031:analogs & derivatives* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D011108:Polymers; C009916:nylon 6; D002209:Caprolactam