Combi Flash 7650 Series Bedienungsanleitung PDF herunterladen (Seite 67)

Section 3 Operation

3-5

3.2.1 Liquid Sample Injection

If the sample is soluble in the starting mobile phase, it can be

prepared as a solution and injected onto the column when

prompted during the purification run.

3.2.2 Solid Samples

Some compounds are not soluble in solvents that are

compatible with the chromatography. In addition, the

compounds may have very limited solubility in any solvent,

resulting in sample volumes that are impractical for good

chromatography. The answer in this case is solid sample

introduction. Here the reaction mixture or dissolved sample is

mixed with the same media in the chromatography column.

Some samples of this type may be simply dissolved and placed

into a prefilled cartridge. You can then use the cartridge

immediately or dry it before placing it on the system.

Other samples may need more care. Typically you would

create a mixture of 20% sample load to media (w/w). Then dry

the mixture under conditions that will drive off the solvent

without affecting the compounds of interest. These compounds

remain bound to the media. Once dried, pour the

media/sample mixture into an empty cartridge.

To prepare an empty solid sample cartridge:

1. Ensure the empty cartridge has a bottom frit.

CAUTION

Missing frits may cause equipment damage, UV detection

problems, or increased maintenance. Frits prevent solids from

entering the fluid path.

2. Prepare the media and sample:

a. Dissolve your sample in a minimal amount of a suitable,

volatile solvent.

b. Place the media into the solvent. If using silica gel, a

particle size of 40–60 µm (240–400 mesh) is

recommended. The amount of silica required is about

four to five times the mass of your sample.

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Combi Flash 7650 Series Bedienungsanleitung Seite 67