Gas separation: processes – Chromatography – With heating or cooling
Reexamination Certificate
1999-04-14
2001-03-20
Spitzer, Robert H. (Department: 1724)
Gas separation: processes
Chromatography
With heating or cooling
C095S089000, C096S105000
Reexamination Certificate
active
06203597
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for mass injection of a sample.
BACKGROUND OF THE INVENTION
One of typical methods of injecting a large quantity of sample during gas chromatography is a PTV (programmed temperature vaporizer) method with or without a split for discharging the solvent. This method calls for a liner disposed at the injection port, and filling the liner with a filler in order to introduce as much sample as possible into the injection port. When in use, the temperature in the injection port has to be maintained so as not to exceed the boiling point of the solvent for the sample. Said method then calls for injecting a great quantity of sample into the injection port so that the sample is retained in the filler; introducing a great quantity of carrier gas in the state where the temperature is still maintained low so that most of the solvent is discharged through a vent line and that the system becomes a splitless state; and introducing the desired constituent that is trapped in the filler in the liner into a column while increasing the temperature in the injection port. Other than the PTV method, various methods on which research and investigations have conventionally been conducted include the on-column mass injection method, which calls for increasing the temperature of the oven and causing pressure equilibrium of the sample in the column in order to remove only the solvent.
A method which calls for filling a split liner with glass wool, a collector or the like to discharge the solvent presents the possibility of the desired constituent remaining in the filler or being decomposed during the thermal desorption process. It is a common knowledge that decomposition actually occurs with some agricultural chemicals. On the other hand, the on-column mass injection method presents a problem in that it takes a long period of time to remove the solvent. Furthermore, as it is difficult to fulfill the conditions for attaining equilibrium in the column, the desired constituent tends to spread into a wide area, thereby necessitating re-condensation.
SUMMARY OF THE INVENTION
In order to solve the above problems, an object of the present invention is to provide a sample injection method and an apparatus for mass injection of a sample, wherein the time required by elimination of a solvent can be reduced by using a splitless liner which is capable of split-purging and by discharging the solvent through the opening of a split purge; no filler is used so that occurrence of residue or decomposition of the desired constituent is prevented; the manner of concentration is at-column concentration conducted at a point in the column so that there is no need of a separate process of re-concentration; there is virtually no influence of the injection rate; and mass injection of a sample is possible. The first feature of the invention lies in providing the injection port with a liner, connecting the column and the liner to a press-fit, evaporating the solvent introduced into the liner, and discharging the evaporated solvent from a discharge port formed at the upper part of the liner. The second feature of the invention lies in providing the injection port with a liner, connecting the column and the liner to a press-fit, introducing a solvent and a sample into the liner and controlling the respective temperatures in the injection port and the oven so as to discharge the evaporated solvent from a discharge port formed at the upper part of the liner while accumulating and concentrating the desired constituent in the sample at the entrance of the column. The third feature of the invention lies in limiting the temperature in the injection port to no higher than the boiling point of the solvent and the temperature of the oven to no lower than the boiling point of the solvent. The fourth feature of the invention lies in providing the injection port with a liner, connecting the column and the liner to a press-fit, providing the body of the injection port with a split, and forming a discharge port for discharging vapor of evaporated solvent at the upper part of the liner.
DETAILED DESCRIPTION OF THE INVENTION
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Furuno Masahiro
Sasano Ryoichi
Yamazaki Kazuhiko
G. L. Scince, Inc.
Oldham & Oldham Co. L.P.A.
Spitzer Robert H.
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