Patent ID: 7347936

Claim:
A liquid chromatograph comprising: an injection section for injecting a sample into a flow passage; an analysis column for separating said injected sample on a per-composition basis; a detector for detecting compositions of the sample separated by said analysis column; a trapping column for concentrating said sample; and a flow passage switching mechanism containing at least a first and second connected multi-port valve, said first multi-port valve having two ports for connecting to said injector section, said second multi-port valve having two ports for connection to said trapping column, said flow passage switching mechanism allowing switching between a concentration flow passage connecting said injection section to said trapping column, a concentration analysis flow passage connecting said trapping column to said analysis column, and a direct analysis flow passage connecting said injection section to said analysis column, such that one or two of said concentration flow passage, said concentration analysis flow passage, and said direct analysis flow passage are activated.