Power gas chromatograph

1、 Overview

Gas chromatography analysis technology is a technique for separating and analyzing multi-component mixtures. It mainly utilizes the differences in boiling point, polarity, and adsorption coefficient of each component in the sample in the chromatographic column to separate each component in the column, and performs qualitative and quantitative analysis on the separated components.

Gas chromatograph uses gas as the mobile phase (carrier gas). When the sample is sent into the injector and vaporized, it is carried by the carrier gas into the packed column or capillary column. Due to the differences in boiling point, polarity, and adsorption coefficient of each component in the sample, each component is separated in the column. Then, the detector connected to the column detects each component in order based on its physical and chemical properties, and sends it to the chromatography workstation through the network. The chromatography workstation records and analyzes the gas chromatogram of each component to obtain the analysis report of each component. The working principle diagram is shown in the following figure:

Due to its high separation efficiency, fast analysis speed, and low sample usage, this analysis method has been widely used in various sectors such as petrochemicals, biochemistry, medicine and health, health quarantine, food inspection, environmental protection, food industry, and medical clinical practice. Gas chromatography has solved problems such as quality inspection, scientific research, pollution detection, and production control of intermediates and industrial products in these fields.

2、 Instrument features

★ It adopts the 100 megabyte/gigabit Ethernet communication interface with excellent technology and built-in P protocol stack, so that the instrument can realize long-distance data transmission through the enterprise's internal LAN and Internet; Facilitating laboratory setup, simplifying laboratory configuration, and facilitating data analysis management;

★ The instrument is designed with three independent connection P addresses, which can be connected to work computers (laboratory site), branch computers (such as quality inspection department, production department, etc.), and executive computers (such as technical supervision bureau, etc.). When needed, it can monitor the operation of the instrument in real time and analyze data results;

★ The workstation equipped with the instrument can simultaneously support the access of multiple chromatographs, enabling data processing and instrument reverse control, simplifying document management;

★ The instrument can be connected to the manufacturer through the Internet to realize remote diagnosis, remote update, etc. (user setting is required);

★ The instrument is equipped with an 8-hour color LCD touch screen that supports hot swapping and can be used as a handheld controller;

★ The instrument adopts a multi processor parallel working mode, making it more stable and reliable; Multiple high-performance detection products can be selected, such as FID, TCD, ECD, FPD, and NPD. Multiple detectors can be installed simultaneously to meet the analysis needs of complex samples.

★ The instrument adopts a modular structural design, which makes maintenance simple and convenient in the later stage.

★ A brand new microcomputer temperature control system with high temperature control accuracy, superior reliability and anti-interference performance; Equipped with eight completely independent temperature control outputs, it can achieve sixteen step programmed heating, and has an automatic rear door opening system for column boxes. Its near room temperature control ability is improved, and the heating/cooling speed is faster;

★ The chromatography machine is equipped with a low-noise, high-resolution 24 bit AD circuit, which has the functions of baseline storage and deduction.

★ The standard workstation is suitable for operating systems such as WinXP, Win2000, Win7, Win8, Win10, etc.

★ The chromatograph microcomputer system with completely independent intellectual property rights has the standard protocol of MODBUS/TCP and can be integrated with DCS systems.

3、 Technical indicators

The transformer oil type gas chromatograph consists of an injector, detector, chromatographic column box, gas flow control system, heating control system, signal detection system, and network data transmission workstation.

3.1 Transformer oil type gas chromatograph

Main technical indicators:

● Operation display: 8 o'clock color LCD touch screen, can be used as a handheld controller

● Temperature controlled area: 8 channels

● Temperature control range: 4 ℃~450 ℃ above room temperature, increment: 1 ℃, accuracy: ± 0.1 ℃

● Program heating order: 16 orders

● Lift rate: 0  1~60℃/min

● Gas path control: precision mechanical valve flow control

● External events: 8 channels; Auxiliary control output 2 channels

● Type of injector: packed column injection, capillary injection, six way valve gas injection, automatic injector

● Number of detectors: 3 (multiple); FID, TCD, ECD, FPD, and NPD are optional

● Start injection: manual or automatic options are available

● Communication interface: Ethernet: IEEE802.3

3.2 Technical indicators of detectors

1. Hydrogen flame ionization detector (FID)

● Detection limit: ≤ 5 × 10-12g/s (hexadecane/isooctane)

● Baseline noise: ≤ 0.07PA

● Baseline drift: ≤ 0.2PA/30min

● Linear range: ≥ 106

2. Thermal conductivity detector (TCD)

● Sensitivity: S ≥ 10000mV · ml/mg (benzene/toluene) (with amplification options of 1, 2, 3, or 4 times)

● Baseline noise: ≤ 20 μ V

● Baseline drift: ≤ 30 μ V/30min

● Linear range: ≥ 104

3. Electron Capture Detector (ECD)

● Detection limit: ≤ 1 × 10-13g/ml (octachlorocyclohexane isooctane solution)

● Baseline noise: ≤ 0.03mV

● Baseline drift: ≤ 0.2mV/30min

● Linear range: 103

● Radioactive source: 63Ni

4. Flame photometric detector (FPD)

● Detection limit: (S) ≤ 5 × 10-11g/s

● (P)≤1×10-12g/s; (Methyl parathion anhydrous ethanol solution)

● Baseline noise: ≤ 3 × 10-13A

● Baseline drift: ≤ 2 × 10-12A/30min

● Linear range: sulfur ≥ 102, phosphorus ≥ 103

5. Nitrogen phosphorus detector (NPD)

● Detection limit: (N) ≤ 5 × 10-13g/s

● (P)≤5×10-13g/s; (Methyl parathion anhydrous ethanol solution)

● Baseline noise: ≤ 5 × 10-13A

● Baseline drift: ≤ 2 × 10-12A/30min

● Linear range: ≥ 102 for nitrogen and ≥ 102 for phosphorus

4、 Usage conditions

Installation environment

The variable pressure oil type gas chromatograph should be used within the temperature and relative humidity ranges of 5-35 ℃ and 0-85%, respectively. But use it in an environment that people feel comfortable with (appropriate constant temperature, constant temperature conditions). Only in this way can the instrument achieve maximum performance and have a long service life.

If the instrument is exposed to corrosive substances (whether gas, liquid, or solid), it will endanger the materials and components of the transformer oil type gas chromatograph and should be avoided.

The test bench for installing the transformer oil type gas chromatograph must be stable. The vibration of the test bench can affect the stability of the instrument. In order to facilitate the discharge of hot air from the column furnace, at least 30cm of space should be left behind the instrument (and no flammable items should be placed behind!), as well as a 30-40cm passage for the installation and maintenance of the chromatograph.

The transformer oil type gas chromatograph requires 10/100M or Gigabit Ethernet. Ethernet can be built using HUB or switches.

Power environment

The power supply for the transformer oil gas chromatograph is 220V ± 10% (50Hz ± 0.5Hz), and the power provided by the electrical energy is not less than 2500W. In order to protect personal safety, the panel and casing of the transformer oil gas chromatograph are grounded with a three core power cord according to the requirements of the International Electrotechnical Association.

Note: In order to reduce the electrical noise of the instrument, it is necessary to have a good grounding.

Warning: It is strictly prohibited to replace grounding wires with water pipes, gas pipes, neutral wires, etc!

gas atmosphere

In order to fully utilize the performance of the transformer oil type gas chromatograph, the gas used must reach the corresponding purity level. We recommend the following purity values.

We suggest installing a purifier on the gas path! After using the gas purifier for a period of time, the molecular sieve and silica gel inside the gas purifier should be activated.