Gas chromatograph for TVOC test in air

Gas chromatograph for TVOC (total volatile organic compounds) test in air

Instrument introduction

There are many definitions of volatile organic compounds (VOCs). For example, the American ASTM D3960-98 standard defines VOCs as any organic compounds that can participate in atmospheric photochemical reactions. The U.S. Environmental Protection Agency (EPA) defines volatile organic compounds as any carbon compound that participates in atmospheric photochemical reactions, except carbon monoxide, carbon dioxide, carbonic acid, metal carbides, metal carbonates, and ammonium carbonate.

TVOC (Total Volatile Organic Compounds) also has various definitions, which generally refers to various measured VOCs. Formaldehyde does not fall into the category of TVOC. The definition of TVOC by the World Health Organization (WHO, 1989) is: the general name for volatile organic compounds with a melting point lower than room temperature and a boiling point range between 50 and 260°C; TVOC is defined in GB/T18883 as: using Tenax GC/ TA sampling, non-polar chromatographic column (polarity index less than 10) is used to analyze volatile organic compounds with retention time between n-hexane and n-hexadecane.

Due to the complexity of indoor air, the TVOC spectrum contains hundreds of peaks, making it difficult to use all standards for one-to-one quantitative analysis. Therefore, nine more toxic organic compounds (benzene, toluene, para/m-xylene, and o-xylene) were selected. , styrene, ethylbenzene, ethyl acetate, undecane) were analyzed qualitatively and quantitatively, and the remaining unknown compounds were calculated as toluene.

SHUOBODA has accumulated more than ten years of experience in gas chromatographs dedicated to environmental air analysis, and has continuously improved and optimized the instruments. The adsorption tube can be inserted directly into the heating block for rapid and even heating, and the desorption effect is good.

Customers can choose one thermal desorption or two thermal desorption injection methods. The primary thermal desorption is direct desorption and injection through the adsorption tube; the secondary thermal desorption is adsorption by the adsorption tube and thermal desorption and injection after secondary cold focusing. The recovery rate is high, the component peak shape is good, and the separation efficiency is high.

HL-802 secondary thermal desorption instrument can be used with different types of gas chromatographs or GC-MS instruments, and the original gas chromatograph can also be modified.

Detection limit

When the sampling volume is 10L, the lower detection limit of the method is 0.5μg/m3.

Applied standards

Standard	Description
GB/T18883-2002	indoor air quality standards
GB50325-2010	Code for indoor environmental pollution control of civil construction projects (2013 edition)

Details specified in the standard

Standard	standard name	subtitle	Remark	collection tube	Injection method
GB/T18883-2002	indoor air quality standards	Testing method for total volatile organic compounds (TVOC) in indoor air (thermal desorption/capillary gas chromatography)	FID, MSD or other detector non-polar capillary column	0.2g~1gTenax	Secondary thermal desorption with cold trap concentration
GB50325-2010	Specifications for indoor environmental pollution control in civil construction projects	Appendix G Determination of Total Volatile Compounds (TVOC) in Indoor Air	FID	0.2gTanax-TA	Thermal desorption direct valve injection

Instrument features

LCD screen or 5.7-inch color touch screen;
Full microcomputer control system, a single computer can control up to 253 chromatographs, with 7-channel temperature control; 8-channel external event time program;
The instrument has a built-in dedicated chromatography workstation for indoor environment monitoring (TVOC), which has intelligent peak identification/automatic processing, multi-channel spectrum integration and exchange, automatically applies toluene to calculate unknown peak content, and can automatically convert the sampling volume to Standard state, and automatically calculate the content of each component and the whole in the unit sampling volume, and can also deduct the peak area of each component in the solvent and the content of each component in the outdoor air sample to obtain the final result, etc.;
The instrument adopts RJ45 network cable interface, which makes signal output and control acquisition simple and convenient. It can realize remote control of the instrument and remote data transmission, processing and supervision. Can be connected to unit supervisors and superior supervisors to facilitate supervision by supervisors;
The large-capacity column oven is equipped with an automatic rear door, which can carry out 8-step program temperature rise, and the column oven has a near room temperature control function (5℃ above room temperature);
It has a fault self-diagnosis function, which can display the fault location and nature at any time; it has an over-temperature protection function, and when the temperature exceeds the set temperature, it will automatically stop heating.
Note: For details about other parameters of the instrument, please refer to the gas chromatography host introduction.
GC9802 gas chromatograph
GC2003 gas chromatograph

Instrument configuration

Primary thermal analysis instrument configuration

product name	Specification	quantity
GC9802 type (networked)	1. GC9802 networked chromatography host; 2. Hydrogen flame ionization detector (FID); 3. Packed column sampler + capillary column sampling system; 4. Primary thermal desorption device sampling system; 5. Special chromatographic column for TVOC analysis; 6. Two-way heating system for the injection valve and output pipeline; 7. Calibration system. 8. Built-in HL-3002 chromatography workstation dedicated for ambient air analysis 9. Spare parts package (including purification tubes, instrument tool accessories, etc.)	1set
Adsorption tube	U-shaped stainless steel, 0.2g Tenax adsorbent	10pcs
Other optional
DA-3000 air generator	Flow: 3L/min, imported oil-free compressor	1set
DH-300 Hydrogen generator	Purity: >99.999%, flow rate: 300ml/min	1set
carrier gas	High purity nitrogen, purity >99.999%, with pressure reducing valve	1bottle
computer	Lenovo, XP or win7 32-bit system	1set
DHX type adsorption tube activation box	Can activate 8 tubes at the same time, with standard sample activation and calibration system	1set
TVOC standard sample (5 pieces/1 set)	TVOC (for thermal desorption method) 9 components (methanol as solvent)	1set
Atmospheric sampler	Atmospheric sampler	1set

Secondary thermal analysis instrument configuration

product name	Specification		Quantity
GC9802 type (networked)	1. GC9802 networked chromatography host; 2. Hydrogen flame ionization detector (FID); 3. Packed column sampler + capillary column sampling system; 4. HL-802 secondary thermal desorption device sampling system; 5. Special chromatographic column for TVOC analysis; 6. Output pipeline heating system; 7. Calibration system. 8. Built-in HL-3002 chromatography workstation dedicated for ambient air analysis 9. Spare parts package (including purification tubes, instrument tool accessories, etc.)	1set
Adsorption tube	U-shaped stainless steel, 0.2g Tenax adsorbent	10pcs
Other optional
DA-3000 air generator	Flow: 3L/min, imported oil-free compressor	1set
DH-300 Hydrogen generator	Purity: >99.999%, flow rate: 300ml/min	1set
carrier gas	High purity nitrogen, purity >99.999%, with pressure reducing valve	1bottle
computer	Lenovo, XP or win7 32-bit system	1set
DHX type adsorption tube activation box	Can activate 8 tubes at the same time, with standard sample activation and calibration system	1set
TVOC standard sample (5 pieces/1 set)	TVOC (for thermal desorption method) 9 components (methanol as solvent)	1set
Atmospheric sampler	Atmospheric sampler	1set

Note: The gas chromatography host GC9802 or GC2003 can be chose .