To Solve Difficulties in Your Experiment - TDS-24RD Perfect Response to HJ734-2014

2026-04-10

On September 2013, 9, the State Council issued the Action Plan for the Prevention and Control of Air Pollution, and formulated a specific implementation plan for ten policies, which is often referred to as the "Ten Atmospheric Measures". This is a major strategic deployment made by the Chinese government on the basis of scientific judgment of the current atmospheric environment situation, which has pointed out the direction for the national air pollution prevention and control work and has become a programmatic document for China's air pollution prevention and control work. In order to fight the tough battle of air pollution control, the national environmental monitoring department has also formulated a series of testing standards and promulgated them. Among them, HJ10-734 "Determination of Volatile Organic Compounds in Waste Gas from Fixed Pollution Sources: Solid Phase Adsorption-Thermal Desorption/Gas Chromatography Mass Spectrometry" is for the determination of 2014 volatile organic compounds in waste gas from fixed pollution sources.
The 24 volatile organic compounds include: acetone, isopropanol, n-hexane, ethyl acetate, benzene, hexamethyldisiloxane, 24-pentanone, n-heptane, toluene, cyclopentanone, ethyl lactate, butyl acetate, propylene glycol monomethyl ether acetate, ethylbenzene, p-/ m-xylene, 3-heptanedone, styrene, o-diluene, anisole, benzaldehyde, 2-decene, 1-nonanone, 2-dodecene.

HJ734-2014 standard has been promulgated and implemented for more than 5 years, and many environmental monitoring departments and third-party environmental testing agencies across the country are implementing this standard, especially in provinces without local standards (such as Guangdong, which has DB44/814-2010 and other four landmarks can be implemented) are using this standard for the determination of volatile organic compounds from fixed pollution sources. However, through visits and investigations, it was found that laboratories encountered some difficult problems when using this standard for testing.
Recently, Taitong Technology and EWG1990 Instrument Learning conducted an experimental survey on the "GCMS Technology 7-Day Training Camp", and a total of 62 experimental institutions participated in this survey, and the survey results are as follows:

结果发现，除24.2%的用户外其他75.8%的使用单位均存在一些仪器使用问题，水溶性组分出峰不好、峰形变形、线性不好、空白残留过高、加标回收率低等为众多用户普遍遇到的问题。
HJ734-2014采用固相吸附-热脱附解析的方法进行，而标准中24中挥发性有机物包涵括的极性范围较大，实验过程捕集肼的捕集难度加大，最终导致丙酮、异丙醇、乳酸乙酯等组分出峰不理想甚至不出峰。

关于空白残留问题：

该标准对各组分的空白残留量也提出较高要求，各组的绝对分残留值参见下表：

序号	组份名称：	空白限度--方法检出限（单位ng)
1	丙酮	3.13
2	异丙醇	0.64
3	正己烷	1.06
4	乙酸乙酯	1.80
5	六甲基二硅氧烷	0.42
6	苯	1.16
7	正庚烷	1.20
8	甲苯	1.23
9	乙酸丁酯	1.39
10	环戊酮	1.18
11	乳酸乙酯	2.19
12	乙苯	1.91
13.14	对间二甲苯	2.81
15	丙二醇单甲醚乙酸脂	1.53
16	邻二甲苯	1.18
17	styrene	1.20
18	2-Heptanone	0.35
19	anisole	1.01
20	1-Decene	0.96
21	benzaldehyde	2.10
22	2-Nonanone	0.86
23	1-Dodecene	2.41
24	3-Pentanone	0.64

To meet the residue required by the standard, high requirements are placed on the entire thermal desorption system. In order to achieve this effect, TDS-24RD invests a lot of R&D effort in industrial structure design and selects highly inert materials for product manufacturing. In addition, a special activation device for sampling tubes that can be deeply activated has been specially developed and launched. The following are the experimental results of TDS-24RD automatic thermal analyzer and ATHH-12 automatic activator:

Component Name:	Component Name:	Blank Limit - Method Detection Limit (in ng)	Measured blank tube residue (unit ng) / just after 100ng injection
1	acetone	3.13	1.92
2	isopropanol	0.64	0.40
3	n-Hexane	1.06	0.08
4	ethyl acetate	1.80	0.43
5	Hexamethyldisiloxane	0.42	0.05
6	benzene	1.16	0.38
7	n-Heptane	1.20	0.04
8	toluene	1.23	0.98
9	Butyl acetate	1.39	0.17
10	Cyclopentanone	1.18	0.44
11	Ethyl lactate	2.19	1.42
12	ethylbenzene	1.91	0.17
13.14	p-m-xylene	2.81	0.24
15	Propylene glycol monomethyl ether acetate	1.53	0.26
16	o-Xylene	1.18	0.22
17	styrene	1.20	0.30
18	2-Heptanone	0.35	0.20
19	anisole	1.01	0.13
20	1-Decene	0.96	0.35
21	benzaldehyde	2.10	1.12
22	2-Nonanone	0.86	0.34
23	1-Dodecene	2.41	0.53
24	3-戊酮	0.64	0.13

关于出峰问题：

丙酮、异丙醇、乳酸乙酯等水溶性物质在试验过程容易峰形变形、出峰偏小甚至不出峰。研究表明，此类问题与除水过程、冷阱结构与选材有着密切关系，以下为TDS-24RD全自动热解析仪的实验效果（10ng标样分析）：

On the linearity question:

The HJ734-2014 standard puts forward clear requirements for the linearity of each component, and R≥0.995. This kind of gas analysis experiment, excluding the influence of human factors of the operator, also puts forward higher requirements for the instrument. The following are the effects of TDS-24RD in laboratory analysis:

1. Experimental instruments: TDS-24RD (24-bit) automatic secondary thermal analysis instrument (Taitong Technology (Guangzhou) Co., Ltd.), ATHH-12 (12-bit) activator (Taitong Technology (Guangzhou) Co., Ltd.), gas chromatography-mass spectrometer EI source, column: 624 60m*0.25mm*1.4um
2. Method conditions:
Thermal desorption conditions: adsorption tube desorption temperature: 350 °C, desorption time: 300s, focused cold trap temperature: -10 °C, focused cold trap desorption temperature: 300 °C, cold trap desorption time: 60s, transmission line temperature: 120 °C, valve temperature: 100 °C
GC/MS conditions: injection port temperature: 220°C, column flow: 1.2ml/min, split ratio: 15:1, column temperature conditions: initial temperature: 40°C, retention 5min, 6°C/min rise to 140°C, then 15°C/min rise to 200°C, retain 5min, full scan mode, scanning range: 33~270amu
3. Sample preparation:
The adsorption tubes (Carbopack C-13mm, Carbopack B-25mm, Carboxen1000-13mm) are fully sealed and ready after being activated by the three-stage program of the ATHH-12 (12-position) activator.
Calibrator formulation: 5 VOC mixed standard solutions with gradient concentrations of 00.10, 0.20, 0.50, 0.100, 24ng/ul.
Standard loading simulated adsorption: the aging adsorption tube is loaded onto the standard loading platform of the ATHH-12 (12-position) activator, and 1ul of standard solutions with different gradient concentrations are injected respectively, and after the suction sweep is completed (the instrument defaults to 3min), each adsorption tube is removed and sealed, and the standard series adsorption tube with content of 5.00, 10.0, 20.0, 50.0, 100ng is obtained.
Note: The external standard was used for this sample test to prove the reliability and stability of the instrument, and no internal standard was added

5NG standard adsorption tube spectrum data