1  范圍

本標(biāo)準(zhǔn)規(guī)定了監(jiān)測(cè)工作場(chǎng)所空氣中酸酐類化合物濃度的方法。

本標(biāo)準(zhǔn)適用于工作場(chǎng)所空氣中酸酐類化合物濃度的測(cè)定。
 

2  規(guī)范性引用文件

下列文件中的條款，通過本標(biāo)準(zhǔn)的引用而成為本標(biāo)準(zhǔn)的條款。凡是注日期的引用文件，其隨后所有的修改單（不包括勘誤的內(nèi)容）或修訂版均不適用于本標(biāo)準(zhǔn)，然而，鼓勵(lì)根據(jù)本標(biāo)準(zhǔn)達(dá)成協(xié)議的各方研究是否可使用這些文件的新版本。凡是不注日期的引用文件，其新版本適用于本標(biāo)準(zhǔn)。

       GBZ 159  工作場(chǎng)所空氣中有害物質(zhì)監(jiān)測(cè)的采樣規(guī)范

3  乙酐的溶劑解吸-氣相色譜法

3.1  原理

空氣中的乙酐用活性碳管采集，丙酮解吸后進(jìn)樣，經(jīng)色譜柱分離，氫焰離子化檢測(cè)器檢測(cè)，以保留時(shí)間定性，峰高或峰面積定量。

3.2  儀器

3.2.1 活性碳管，溶劑解吸型，內(nèi)裝100mg/50mg 活性碳。

3.2.2 空氣采樣器，流量0~500ml/min。

3.2.3 溶劑解吸瓶，5ml。

3.2.4 微量注射器，10l。

3.2.5 氣相色譜儀，氫焰離子化檢測(cè)器。

儀器操作條件

色  譜  柱：2m×4mm，Tenax；

柱      溫：135℃；

汽化室溫度：200℃；

檢測(cè)室溫度：200℃；

載氣（氮?dú)猓┝髁浚?5ml/min。

3.3  試劑

3.3.1 丙酮，色譜鑒定無干擾雜峰。

3.3.2 Tenax，60～80目。

3.3.3 標(biāo)準(zhǔn)溶液：于25ml 容量瓶中，加約5ml 丙酮，準(zhǔn)確稱量后，加入2～3 滴乙酐，再準(zhǔn)確稱量，用丙酮稀釋刻度，由兩次稱量之差計(jì)算溶液的濃度，為標(biāo)準(zhǔn)貯備液。臨用前，用丙酮稀釋成1.0mg/ml 乙酐標(biāo)準(zhǔn)溶液?；蛴脟艺J(rèn)可的標(biāo)準(zhǔn)溶液配制。

3.4  樣品的采集、運(yùn)輸和保存

現(xiàn)場(chǎng)采樣按照GBZ 159執(zhí)行。

3.4.1 短時(shí)間采樣：在采樣點(diǎn)，打開活性碳管兩端，以200ml/min 流量采集15min 空氣樣品。

3.4.2 長(zhǎng)時(shí)間采樣：在采樣點(diǎn)，打開活性碳管兩端，以50ml/min 流量采集2~8h 空氣樣品。

3.4.3 個(gè)體采樣：在采樣點(diǎn)，打開活性碳管兩端，佩帶在采樣對(duì)象的前胸上部，進(jìn)氣口盡量接近呼吸帶，以50ml/min 流量采集2~8h 空氣樣品。

采樣后，立即封閉活性碳管兩端，置清潔容器內(nèi)運(yùn)輸和保存。樣品在室溫下可保存7d。

3.5  分析步驟

3.5.1  對(duì)照試驗(yàn)：將活性碳管帶采樣點(diǎn)，除不連接空氣采樣器采集空氣樣品外，其余操作同樣品，作為樣品的空白對(duì)照。

3.5.2  樣品處理：將采過樣的前后段活性碳分別倒入溶劑解吸瓶中，加入2.0ml 解吸液，蓋緊瓶蓋，振搖1min，解吸30min。解吸液供測(cè)定。若解吸液中乙酐濃度超過測(cè)定范圍，可用丙酮稀釋后測(cè)定，計(jì)算時(shí)乘以稀釋倍數(shù)。

3.5.3 標(biāo)準(zhǔn)曲線的繪制：用丙酮稀釋標(biāo)準(zhǔn)溶液成0.0、10.0、20.0、50.0、100和500mg/ml乙酐標(biāo)準(zhǔn)系列。參照儀器操作條件，將氣相色譜儀調(diào)節(jié)操作條件，分別進(jìn)樣2.0l，測(cè)定各標(biāo)準(zhǔn)系列。每個(gè)濃度重復(fù)測(cè)定3 次。以測(cè)得的峰高或峰面積均值對(duì)乙酐濃度(mg/ml)繪制標(biāo)準(zhǔn)曲線。

7.4 樣品測(cè)定：用測(cè)定標(biāo)準(zhǔn)系列的操作條件測(cè)定樣品和空白對(duì)照的解吸液；測(cè)得的樣

品峰高或峰面積值減去空白對(duì)照峰高或峰面積值后，由標(biāo)準(zhǔn)曲線得乙酐的濃度(mg/ml)。

工作場(chǎng)所空氣有毒物質(zhì)測(cè)定乙酸酐  測(cè)試譜圖：


Determination of Toxic Substances in Workplace Air for Acetic Anhydride
Determination of Acetic Anhydride for Toxic Substances in Workplace Air Details:

Name: Packed Column
Stationary Phase: Polymer Microspheres
Granularity: 60-80 mesh
Specifications: 2M*4MM
Model: Tenax
Application: Determination of toxic substances in workplace air Determination of acid anhydride compounds

1 Scope

This standard specifies a method for monitoring the concentration of acid anhydride compounds in the workplace air.

This standard applies to the determination of the concentration of acid anhydride compounds in the workplace air.
 

2 Normative references

The clauses in the following documents, through reference in this standard, become clauses of this standard. For dated references, all subsequent amendments (excluding errata content) or revisions do not apply to this standard. However, parties to agreements based on this standard are encouraged to study whether the latest versions of these documents can be used. . For undated references, the latest edition applies to this standard.

       GBZ 159 Sampling Specifications for Monitoring Hazardous Substances in Workplace Air

 

3 Solvent Desorption of Acetic Anhydride-Gas Chromatography



3.1 Principle

Acetic anhydride in the air was collected by activated carbon tube, desorbed by acetone and injected, separated by a chromatographic column, detected by a hydrogen flame ionization detector, qualitatively determined by retention time, and quantified by peak height or peak area.



3.2 Instruments

3.2.1 Activated carbon tube, solvent desorption type, filled with 100mg/50mg activated carbon.

3.2.2 Air sampler, flow rate 0~500ml/min.

3.2.3 Solvent desorption bottle, 5ml.

3.2.4 Micro syringe, 10l.

3.2.5 Gas chromatograph, hydrogen flame ionization detector.

Instrument operating conditions

Chromatographic column: 2m×4mm, Tenax;

Column temperature: 135℃;

Vaporization chamber temperature: 200℃;

Detection room temperature: 200℃;

Carrier gas (nitrogen) flow: 35ml/min.



3.3 Reagents

3.3.1 Acetone, chromatographic identification without interference peaks.

3.3.2 Tenax, 60-80 mesh.

3.3.3 Standard solution: add about 5ml of acetone to a 25ml volumetric flask, after accurate weighing, add 2 to 3 drops of acetic anhydride, then accurately weigh, dilute with acetone to the mark, and calculate the solution from the difference between the two weighings The concentration is the standard stock solution. Just before use, dilute with acetone to 1.0mg/ml acetic anhydride standard solution. Or prepared with a nationally recognized standard solution.



3.4 Collection, transport and storage of samples

Field sampling is performed in accordance with GBZ 159.

3.4.1 Short-time sampling: at the sampling point, open both ends of the activated carbon tube and collect air samples at a flow rate of 200ml/min for 15min.

3.4.2 Long-term sampling: at the sampling point, open both ends of the activated carbon tube and collect air samples at a flow rate of 50ml/min for 2~8h.

3.4.3 Individual sampling: At the sampling point, open both ends of the activated carbon tube, wear it on the upper chest of the sampling object, with the air inlet as close to the breathing belt as possible, and collect air samples at a flow rate of 50ml/min for 2~8h.

Immediately after sampling, both ends of the activated carbon tube were closed and transported and stored in a clean container. Samples can be stored for 7 days at room temperature.



3.5 Analysis steps

3.5.1 Control test: Bring the activated carbon tube to the sampling point, and operate the same sample as the blank control of the sample except that the air sample is not connected to the air sampler.

3.5.2 Sample processing: Pour the sampled front and back activated carbons into the solvent desorption bottle respectively, add 2.0ml of desorption solution, close the bottle cap tightly, shake for 1min, and desorb for 30min. Desorbed solution for measurement. If the concentration of acetic anhydride in the desorbed solution exceeds the measurement range, it can be diluted with acetone and measured, and multiplied by the dilution factor when calculating.

3.5.3 Drawing of the standard curve: Dilute the standard solution with acetone into a standard series of 0.0, 10.0, 20.0, 50.0, 100 and 500 mg/ml acetic anhydride. Referring to the operating conditions of the instrument, adjust the gas chromatograph to the optimum operating conditions, inject 2.0 l of samples respectively, and measure each standard series. Each concentration was repeated 3 times. A standard curve was plotted with the measured peak height or peak area mean versus acetic anhydride concentration (mg/ml).

7.4 Determination of sample: Determination of sample and blank control desorption solution using the operating conditions of the standard series;

After subtracting the blank control peak height or peak area value from the peak height or peak area value of the product, the concentration of acetic anhydride (mg/ml) was obtained from the standard curve.

Determination of acetic anhydride for toxic substances in workplace air Test spectrum: