SU1352222A1 - Method of metering liquid to gas chromatograph - Google Patents

Description

113

The invention relates to analytical instrumentation and can be used in the dosing of a liquid sample into chromatographic systems.

The purpose of the invention is to improve the accuracy of dosing, improve the reproducibility of the analysis, simplify the instrumentation, and also simplify the calibration of the chromatograph.

FIG. Figures 1 and 2 depict the spool dispenser, respectively, at the sampling and insertion position for carrying out the proposed method.

The dispenser consists of a spool 1, an additional calibrated volume 2.dl for taking a dose of high-pressure gas, a calibrated volume 3 for sampling a liquid dose, fixed plates 4. The output channel 5 of the dispenser is connected to the chromatograph evaporator 6, a gas is connected to the connecting line between them. carrier.

In the liquid sampling position, the flow of the analyzed liquid flows through volume 3 with a capacity of V ,. The high pressure gas flow passes through the connecting channels and the groove in the spool into a calibrated

volume 2 with capacity V, and the pressure in this gas line is kept constant and equal to P. The carrier gas under constant pressure P2 is supplied to the evaporator 6, which, including the outlet channel 5 and the connecting lines, is equal to V. When the spool moves in calibrated volumes 2 and 3, the doses of gas with pressure P, respectively, are cut off displacement of the spool leads to the message of calibrated volumes 2 and 3 between themselves and with the evaporator 6. If P is not equal to P, then when combining the dosed volumes 2 and 3, the high-pressure gas in volume 2 expands and displaces the dose of liquid to the evaporator chromate Count. The ejection of a dose of liquid occurs until the pressure P and PO are equal, i.e. the outcome of the law of Boyle, and, taking into account non-approximate possible. , . + V), then the main condition for the choice of pressure R. and P „will be the following dependence:

liquid capacity, write: P, -V,

;

Vrt

V,

If a high-pressure mixture with a known component content is used as a high-pressure gas, the amount of the latter is dosed when the liquid sample is introduced into the evaporator. To calculate the chromatograms in this case it is advantageous to use the internal standard method. The accuracy of the dosing and reproducibility of the chromatographic analysis is determined only by the stability of the pressures in the gas sample and the carrier gas. P and PJ do not depend on the response time of the movement mechanism. A device for implementing the proposed method is characterized by simplicity of design.

Claims (2)

Invention Formula 25 35 zo 1, a method for dispensing a liquid into a gas chromatograph by pushing a dose of liquid into a chromatograph evaporator with high pressure gas, characterized in that, in order to improve the accuracy of dosing, improve the reproducibility of the analysis and simplify the instrumentation, first take a volume dose of gas and eject the dose of liquid due to the expansion of this dose. gas, and the gas pressure in the dose and the pressure in the evaporator is chosen from the ratio il Pi, V + 7 V, where P and PJ Vr. V, and U „ respectively, the pressure in the gas dose and the gas pressure in the evaporator, respectively, the volume of the dose of gas, the dose of liquid and evaporator. 2. The method according to claim 1, wherein and in order to simplify the calibration of the chromatograph, a reference mixture is used as the high-pressure gas. L / U- / FG