Life Sciences/Chemical Analysis Online Store
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Filtration of Contaminants
Frits, also referred to as filters, remove contaminants. Within HPLC in order to achieve ultra sensitive results, it is vital to start with a clean mobile phase. There are a number of methods required to obtain a clean mobile phase. As you know, only very pure solvents should be used for the HPLC. Solvent impurities can result in baseline shifts and detector noise. Impurities will contaminate collected fractions and, if present in the weak eluent of a gradient separation, can cause ghost peaks in the chromatogram. External Filtration Considering the time and effort required producing pure solvents, the cost of commercial HPLC grade solvents is usually justified. However, all eluents, even those made from HPLC grade solvents, require further preparation. Preparation steps include:
Both the eluent and the sample must be filtered for several reasons:
There are two methods for external filtration:
Disposable Syringe Filters Syringe filters are convenient for filtering the sample. Agilent offers a variety of different membrane types and pore sizes. The filters are all based on cellulose materials that because of carefully controlled pore sizes offer good flow rates with minimal flow resistance. In-line Filtration
For in-line method filtration, the Agilent HPLC instrument provides intake and outlet filters installed within the system to trap wear particles. The three types of filters within the Agilent 1100 HPLC system are the inlet filter, the inlet valve and the outlet filter. It is important to change all filters on a regular basis to prevent instrument malfunctions.
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Solvent Filter/Degassers