Hitachi, Ltd.

Katsuo Tsukada

Hironori Kaji

Taro Nogami

Yoshinori Takata

Sadabumi Ohnuma

Kaoru Hagiya

A liquid chromatography system and a method of utilizing the same, comprising a plurality of separated-component vessels for collecting components eluted in a separation column, a flowing system conduit for component extraction through which the components separated in the separation column are individually delivered to the separated-component vessels. The system further comprises a flowing system conduit for sample introduction through which any of the separated components collected in the plurality of separated-component vessels is selectively drawn from its vessel and introduced to the upstream side of the separation column. The present invention allows a plurality of components in a sample of a mixture to be individual collected, and also allows any of the collected components to be re-separated selectively and automatically.

Liquid chromatography system and method for separation of pre-separated

A plurality of liquid mobile phases stored in a plurality of reservoirs respectively are filled and pumped by a dual pump driven by a stepping motor, through valves complementarily subjected to on-off control by a gradient programmer. The dual pump has two pistons in contact with the periphery of a cam in opposition to each other at 180 degrees, which pistons fill and pump the liquid mobile phases by linear reciprocation along the contour of the cam with the rotation of the cam. The radius of the cam linearly increases in the range from 0 to 180 degrees and linearly decreases in the range from 180 to 360 degrees at the same rate as when it increases. An electric signal is produced from a timing device during a period from the rotational positions of the cam reaches 0 and 180 degrees to a predetermined rotational positions. The liquid mobile phase delivered from the dual pump is supplied to a pressure transducer, and after passing through it, supplied to a column through an injector for injecting a specimen. The components into which the specimen is separated are detected by a detector. When the timing device detects that the cam is positioned in intervals from 0 and 180 degree to a predetermined angle therefrom, the motor control circuit drives the stepping motor at high speed during period from a time which the time derivative of the back pressure signal from the pressure transducer reaches value smaller than a predetermined value to a time it reaches value larger than the predetermined value.

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Ibaraki, Japan

Katsuo Tsukada