Konstruktion eines vollautomatischen präzisionschromatographen auf der basis der phasendistributionschromatographie (PDC)

Abstract

The design of a fully automatized chromatograph based on Phase Distribution Chromatography (PDC) is presented and some of the most important results of the measurements shown. PDC represents a dynamical phase separation as column method: the separation of the polymer components in a PDC‐column is based on thermodynamic‐kinetical interactions of the mobile phase (the polymer to be analyzed) below the theta temperature of the system by a gel of the same high polymer situated on the surface of small glass beads. The sigmoidal shape of the measured PDC calibration curves can be explained by introducing a dynamical flow‐equilibrium in the system sol/gel which highly differs from the thermodynamic equilibrium at low temperatures of the column.

Separation of linear and star‐shaped polystyrenes by phase distribution chromatography

“…20% after rinsing. This value is in good agreement with former investigations 16. The deviation between theoretically and experimentally found values is caused by the removal of the soluble parts of the UHPS during the coating procedure.…”

“…In order to simplify the separation process, modular build system consisting of a pump, an injection system, a PDC‐column and a detector system was used instead of the time‐consuming, manual fractionation described above. Therefore, an empty chromatographic column (length=300 mm, Ø=7.8 mm) was filled with coated Ballotini under reduced pressure and repeated rotation of the column 16 to obtain dense packing (column type 1, Table 2). The injection volume during the subsequent experiments was 50 μL and the sample concentration about 2 mg/mL if not mentioned in another way.…”

“…However, temperatures lower than this are used for better separation results, due to the solubility of UHPS and the low resolution near to this region 15. The theoretical background of PDC was extensively investigated and explained by Greschner 16–20 including the thermodynamics of molecular transport, the flow equilibrium and the deformation concept.…”

Phase distribution chromatography (PDC) as a method for the investigation of polymers in solution 1. Thermodynamics and transport

“…9 and 10 of ref. 4). The left part of such a curve from P = 0 to the corresponding inflection point can approximately be described by Eq.…”

“…Let mpBs and mp,, be the polymer masses of the considered P-mer in the sol and the gel, respectively, cp,s and cP,, the corresponding concentrations, u(P) = (dz/dt), the elution rate of the transported P-mer along the z-axis of the vertical column, and 6 the mean over-all linear rate of the column liquid; then a trivial integration of the thermodynamically and hydrodynamically defined retention coefficient of the P-mer in the column gives the equation of the PDC-column in a reversible thermodynamic equilibrium, if u(P) is constant to z and t: V ( P ) = V, 1 + -K ( P ) [ rL (3) In Eq. (3) V(P) is the elution volume of the P-mer measured at the elution time tE (P) and the position z = L of the thermostated column, V ( P ) = q li tE(P) (4) Vo the zero-volume (Eq. (1)) of this column, Vs and VG the volume of the sol and the gel, respectively, and the quantity K ( P ) = cp,g/cp,s = exp M T ) + el (T)P"(?…”