RU83849U1 - TWO-CHANNEL GAS CHROMATOGRAPH FOR IDENTIFICATION OF FALSE ALCOHOL AND VOLATILE POISONS - Google Patents

Abstract

A two-channel gas chromatograph for detecting falsified alcohol and volatile poisons, including a sample inlet device, an injector, a column, and a detector duplicated in a single thermostat and connected to a common unit for the automatic control of the analysis process, characterized in that it includes a mass-selective detector as detectors one channel and a flame ionization detector in another and additionally includes a block from a chromatographic column connected to a mass selective detector, and switching blocks feeding the analyzed sample from the input device of each channel and carrier gases to both injectors, while the input device of the sample of one channel is equipped with a syringe socket for injecting liquid samples, and the other with a syringe socket for injecting gas-vapor samples, and a block from the chromatographic column with mass-selective the detector is connected to the injector of the second channel.

Description

The utility model relates to chromatographic analytical systems and can be used for production and technical operations, for example, in the analysis and identification of chemical compounds, and in particular for the detection of falsified alcohol and volatile poisons.

A gas chromatograph is known, including a sample injection device, an injector, a column, a detector and a thermostat, as well as an automatic analysis control system. [one]

The disadvantage of this chromatograph is the inconvenience in operation, in particular, the replacement of the carrier gas involves the re-installation of the gas supply line, which significantly lengthens the analysis; analysis of vapor-phase and liquid-phase samples involves the manual change of the corresponding syringes in the device for introducing the sample. In addition, this device does not allow a complete analysis of falsified alcohol, because with its help it is practically impossible to determine some volatile poisons (for example, 1,2-dichloroethane) or one of the main components of falsified alcohol - benzene against a background of ethanol.

The closest to the proposed utility model in essence and the technical result achieved is the Agilent 6890 Series dual-channel gas chromatograph (GC System), which includes a sample inlet duplicated in one thermostat, an injector,

a column and a detector connected to a system-wide automatic control unit for the analysis. [2]

The disadvantage of this chromatograph, as well as the aforementioned analogue, is the inconvenience of operating to replace the carrier gas, the technique for analyzing vapor-phase and liquid-phase samples, and, moreover, this device also does not allow a complete analysis of falsified alcohol and volatile poisons.

The technical result, the achievement of which the creation of this utility model is aimed, is to expand the functionality of the analytical system by giving it the function of recognizing falsified alcohol and volatile poisons and ensuring reliable identification results.

The technical result is achieved in that the two-channel gas chromatograph as detectors includes a mass-selective detector in one channel and a flame-ionization detector in another and further includes a unit from a chromatographic column connected to the mass-selective detector and blocks for switching the supply of the analyzed sample from the input device each channel to both injectors and carrier gases to both injectors, while the input device of the sample of one channel is equipped with a syringe socket for introducing liquid samples, and rugogo - syringe socket for input of samples and a block of steam and gas from the chromatographic column with a mass selective detector connected to the second injector duct.

The authors, based on their knowledge and experience, argue that they found an unexpected solution. In fact, the correct way to identify

counterfeit alcohol and volatile poisons, and one of the main signs of the first is the presence of a volatile component - isopropanol, and the second - 1.2 dichloroethane, methanol and glycols, etc., involves the analysis of gas-vapor and liquid phases in at least two modes of conditioning the temperature gradient with by changing the carrier gas (possibly also dividing the flow) and using mass-selective and flame-ionization detectors (which is generally not absolutized), the first being used in the analysis of “screened” volatile components in falsified alcohol, and the second in the analysis of volatile or volatile non-volatile (glycols), which involves either conducting this analysis step on another chromatograph with a mass-selective detector, or changing the carrier gas, and the authors believe that cross-use of detectors is the way out of this situation and / or reorienting the sample stream from one channel to another.

The claimed utility model is just designed to solve such cases.

As a gas chromatograph, commercially available chromatographs can be used, for example, Crystallux-4000M, EVD-3000, Agilent 6890N or 6850, equipped with autosamplers.

As detectors can be used flame ionization or mass selective detectors, for example Agilent 5973N.

As columns, standard commercially available columns can be used, for example, HP-FFAP (19091F-115F), PORA PLOTQ.

As the carrier gas can be used helium, nitrogen, hydrogen.

As a block for automatic control of the analysis, blocks with appropriate software can be used to control the analysis and record analysis data.

The procedure and methods for connecting devices and units in the inventive chromatograph with each other are essential only in the sense that to ensure the operability of the inventive system.

In the considered embodiment of the utility model, the FF-FFAP column (19091F - 115F) is used in both channels and the PORA PLOTOQ column in the chromatographic column - flame ionization detector block.

The scheme of the inventive two-channel gas chromatograph is presented in figure 1. Figure 2, 3 and 4 presents embodiments of the block switching the supply of the analyzed samples to the injectors, the switching block of the carrier gas, respectively, and the switching circuit of the sample supply.

A two-channel gas chromatograph is (see FIG. 1) a sample inlet device 2, injector 3, column 4 and mass-selective detector 5 of the first channel, sample inlet 6, injector 7, column 8, functionally interconnected and equipped with a common thermostat 1 and a flame ionization detector 9 of the second channel and a unit from the chromatographic column 10 connected to the injector 7 of the second channel connected to the flame ionization detector 11. The sample input device 2 and the sample input device 6 through the feed switching unit are analyzed oh samples 12 are each connected with injectors 3 and 7 with which the gas supply carrier switching unit 13 is also connected. In device

the sample inlet 2 contains a syringe nest 14 for introducing liquid samples, and in the sample input device 6 there is a syringe nest 15 for injecting gas-vapor samples.

An embodiment of the block for switching the supply of the analyzed sample is presented in figure 2.

The block is a system of capillaries 16 and 17 connected by a jumper 18 and equipped with solenoid valves (EMC) 19, 20, 21, 22 and 23 at the inlet, outlet, and jumper.

An embodiment of a unit for switching a carrier gas supply to injectors is shown in FIG. 3.

The block is a comb of capillaries 24, 25 and 26 for supplying carrier gases connected to a closed capillary frame with outputs 27 and 28 to the injectors and equipped with an EMK system 29-34 for switching the flow of carrier gas to the injectors.

A variant of the sample supply switching circuit is shown in FIG. 4.

The scheme consists of branched capillaries 35 and 36 interconnected with EMC 37 and 38 located on them, injector 7 of the second channel and chromatographic columns 8 and 10.

Note: In the presented figures, the block of automatic control of the analysis progress, as well as the communication between the indicated block and the blocks and nodes of the two-channel gas chromatograph, are not shown.

The system works as follows.

The test sample is prepared, divided into two aliquots - for liquid-phase and vapor-phase analysis, collect them in the appropriate syringes and place the syringes in the nests 14 and 15 of the sample input devices 2 and 6.

Next, in the block switching the supply of the analyzed sample (see Figure 2) open EMC 20, 21, 22 and 23, and EMC 19 is closed. In the switching circuit of the sample supply (see Figure 4), the EMCs 37 and 38 are opened. In the switching block of the carrier gas supply (see Figure 3), the EMCs 29 and 30 are opened, and the EMCs 31, 32, 33 and 34 are closed. Thus, the gas-phase sample is supplied to the injector 3 of the first channel and to the injector 7 of the second channel, the carrier gas helium is supplied to the injector 3 of the first channel and to the injector 7 of the second channel. Next, they include an automatic control unit for the analysis, including autosamplers, and register signals from detectors 5, 9, and 11. The components of falsified alcohol — isopropanol, methanol, benzene, and others — are determined by this scheme.

Then switch the EMC in block 12 according to the following scheme: EMC 19, 21 and 23 open, EMC 20 and 22 are closed. In the scheme (see Figure 4) EMC 37 and 38 open. In the carrier gas switching system (see FIG. 3), the EMC 34 is opened; EMC 29, 30, 31, 32 and 33 - open. Thus, the liquid-phase sample is supplied to the injector 7 of the second channel and then with the carrier gas to the column 10 and the detector 11. A nitrogen carrier gas is supplied to the injector 7. The signals of detectors 9 and 11 are taken and recorded. The indicated circuit allows one to determine glycols (volatile non-volatile), as well as organochlorine compounds.

It is obvious that the claimed utility model can implement a large number of possible schemes for combining the options for supplying the analyzed sample (analyzed samples) and carrier gas to the injectors and, accordingly, the schemes for carrying out the analysis procedure, which gives it great flexibility and expands its functionality.

As can be seen from the description and operation example of the claimed utility model, it has expanded functional capabilities due to giving it the function of recognizing counterfeit alcohol and volatile poisons and providing reliable identification results.

Sources of information taken into account when preparing the application:

1. Agilent 6850 Series (GC System), 1998

2. Agilent 6890 Series (GC System), 1998 - prototype

Claims (1)

A two-channel gas chromatograph for detecting falsified alcohol and volatile poisons, including a sample inlet device, an injector, a column, and a detector duplicated in a single thermostat and connected to a common unit for the automatic control of the analysis process, characterized in that it includes a mass-selective detector as detectors one channel and a flame ionization detector in another and further includes a unit from a chromatographic column connected to a mass selective detector, and switching units feeding the analyzed sample from the input device of each channel and carrier gases to both injectors, while the input device of the sample of one channel is equipped with a syringe socket for injecting liquid samples, and the other with a syringe socket for injecting gas-vapor samples, and a block from the chromatographic column with mass-selective the detector is connected to the injector of the second channel.