Method and apparatus to control sample carryover in analytical instruments

摘要

A method and apparatus are disclosed which enable the reduction of sample carryover in the measurement cell of an analytical instrument. A sample cell is defined as a region sealed within a first o-ring. Located outside of said sample region is another o-ring which seals and defines a seal wash region as the region between the first and second o-ring. After the fluid sample is injected into the measurement cell a pressure is applied to the seal wash region, forcing the first o-ring to the innermost extent of the groove in which it sits, expelling any trapped solvent and removing from the measurement cell a significant dead volume while the cell is flushed and prepared for a new sample and corresponding measurement.

主权项

1. An apparatus for controlling sample carryover in an analytical instrument comprising
A) a sample measurement cell including a measurement chamber into which a liquid sample may be injected; B) a first o-ring seated within a first o-ring groove, said first o-ring sealing said measurement chamber of said sample cell; C) a second sealing means located around said first o-ring groove; and D) a seal wash region of said measurement cell, said seal wash region being bounded on one side by said first o-ring and on the other side by said second sealing means and connected to a fluid port;wherein said measurement chamber of said measurement cell and said seal wash region of said measurement cell are capable of receiving a pressure adequate to move or deform said first o-ring from its initial lateral position within said first o-ring groove to a position wherein it is compressed against a wall, expelling thereby a quantity of fluid contained within said first o-ring groove.