11.23 : 超临界流体色谱法

Supercritical fluid chromatography, or SFC, is a hybrid technique with behavior between liquid and gas chromatography that uses a supercritical fluid—often carbon dioxide—as the mobile phase.

Supercritical fluids are formed by heating and pressurizing a substance to above its critical temperature and pressure.

The viscosity of a supercritical fluid is almost as low as that of its gas, while the density is close to that of its liquid. Its diffusion coefficient is between those of the gas and liquid.

So, SFC has faster and more efficient separation than LC does, but it's less affected by longitudinal diffusion than GC is. Importantly, it shares LC's compatibility with analytes that are difficult to volatilize.

SFC instruments are similar to standard HPLC instruments, except for a GC-like thermostatted column oven and a special pressure restrictor that maintain the mobile phase conditions.

SFC can use both open tubular and packed columns, which lets it employ detectors used with GC and HPLC, respectively. It is also easily coupled with MS and FTIR.