GBZT300.68-2017 PDF English
US$110.00 · In stock · Download in 9 secondsGBZT300.68-2017: Determination of toxic substances in workplace air - Part 68: Styrene, methylstyrene and divinyl benzene Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedureStatus: Valid
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GBZ/T 300.68-2017 | English | 110 |
Add to Cart
|
0-9 seconds. Auto-delivery
|
Determination of toxic substances in workplace air - Part 68: Styrene, methylstyrene and divinyl benzene
| Valid |
Excerpted PDFs (Download full copy in 9 seconds upon purchase)PDF Preview: GBZT300.68-2017
GBZ/T 300.68-2017: Determination of toxic substances in workplace air - Part 68: Styrene, methylstyrene and divinyl benzene
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBZT300.68-2017
GBZ
NATIONAL OCCUPATIONAL HEALTH STANDARD
OF THE PEOPLE'S REPUBLIC OF CHINA
ICS 13.100
C 52
Partially replacing GBZ/T 160.42-2007
Determination of toxic substances in workplace air - Part 68.
Styrene, methylstyrene and divinyl benzene
Issued on: NOVEMBER 9, 2017
Implemented on: MAY 1, 2018
Issued by. National Health and Family Planning Commission of PRC
Table of Contents
Foreword... 3
1 Scope... 4
2 Normative references... 4
3 Basic information on styrene, methylstyrene and divinylbenzene... 4
4 Solvent desorption-gas chromatography of styrene and methylstyrene... 5
5 Thermal desorption-gas chromatography of styrene... 8
6 Solvent desorption-gas chromatography of divinylbenzene... 11
Determination of toxic substances in workplace air - Part 68.
Styrene, methylstyrene and divinyl benzene
1 Scope
This part of GB/T 300 specifies the solvent desorption-gas chromatography method for
the determination of styrene, methylstyrene and divinylbenzene in the air of the
workplace and the thermal desorption-gas chromatography method for the
determination of styrene.
This part applies to the determination of the concentrations of vaporous styrene, methyl
styrene and divinylbenzene in the air of the workplace.
2 Normative references
The following documents are essential for the application of this document. For any
referenced document with a date, only the version with the date is applicable to this
document. For any referenced document without a date, the latest version (including all
amendments) is applicable to this document.
GBZ 159 Specifications of air sampling for hazardous substances monitoring in
the workplace
GBZ/T 210.4 Guide for establishing occupational health standards - Part 4.
Determination methods of air chemicals in workplace
3 Basic information on styrene, methylstyrene and
divinylbenzene
The basic information on styrene, methylstyrene and divinylbenzene is shown in Table
1.
a) Chromatographic column. 30 m×0.32 mm×0.5 μm, FFAP;
b) Column temperature. 80 °C;
c) Vaporization chamber temperature. 150 °C;
d) Testing room temperature. 150 °C;
e) Carrier gas (nitrogen) flow rate. 1 mL/min;
f) Split ratio. 10.1.
4.3 Reagents
4.3.1 Carbon disulfide. No interfering peaks are found in chromatographic
identification.
4.3.2 Standard solution. Add carbon disulfide to a volumetric flask, weigh it accurately,
then add a certain amount of styrene and/or methyl styrene, weigh it accurately again,
and make up the volume with carbon disulfide. Calculate the concentration of the
solution from the difference in weight, which is the styrene and/or methyl styrene
standard solution. Or prepare it with a nationally recognized standard solution.
4.4 Sample collection, transportation and storage
4.4.1 On-site sampling shall be carried out in accordance with GBZ 159.
4.4.2 Short-time sampling. At the sampling point, use an activated carbon tube to collect
air samples at a flow rate of 100 mL/min for 15 minutes.
4.4.3 Long-term sampling. At the sampling point, use an activated carbon tube to collect
air samples at a flow rate of 50 mL/min for 2~8 hours.
4.4.4 After sampling, immediately seal both ends of the activated carbon tube and place
it in a clean container for transportation and storage. The sample can be stored in a
refrigerator for 14 days.
4.4.5 Sample blank. At the sampling point, open both ends of the activated carbon tube
and seal them immediately, then transport, store and measure together with the sample.
Each batch of samples shall have no less than 2 sample blanks.
4.5 Analysis steps
4.5.1 Sample treatment. Place the front and rear section activated carbon into two
solvent desorption bottles respectively, add 1.0 mL of carbon disulfide to each, seal,
and desorb for 30 minutes, shaking occasionally. The sample solution is for
determination.
4.6.3 The time-weighted average exposure concentration (CTWA) in the air shall be
calculated in accordance with the provisions of GBZ 159.
4.7 Description
4.7.1 This method is developed in accordance with the method and requirements of
GBZ/T 210.4.The detection limit of this method is 2.5 μg/mL, the lower limit of
quantification is 8.3 μg/mL, and the quantitative determination range is 8.3 μg/mL~900
μg/mL; based on the collection of 1.5 L air sample, the minimum detection
concentration is 1.7 mg/m3, and the minimum quantitative concentration is 5.5 mg/m3;
the relative standard deviation is 4.2%~5.3%, the penetration capacity (100 mg of
activated carbon) is 6.9 mg, and the desorption efficiency is 79.5%. The desorption
efficiency of each batch of activated carbon tubes shall be measured.
4.7.2 This method can also be used with other equivalent gas chromatographic columns.
Constant temperature measurement or programmed temperature measurement can be
selected according to the measurement requirements.
5 Thermal desorption-gas chromatography of styrene
5.1 Principle
The vaporous styrene in the air is collected by activated carbon, injected after thermal
desorption, separated by a gas chromatography column, and detected by a hydrogen
flame ionization detector. The retention time is used for qualitative analysis and the
peak height or peak area is used for quantitative analysis.
5.2 Instruments
5.2.1 Activated carbon tube. thermal desorption type, containing 100 mg of activated
carbon.
5.2.2 Air sampler. with a flow range of 0 mL/min～500 mL/min.
5.2.3 Thermal desorber.
5.2.4 Syringe. 1 mL, 100 mL.
5.2.5 Gas chromatograph with a hydrogen flame ionization detector. Reference
operating conditions.
a) Chromatographic column. 30 m×0.32 mm×0.5 μm, FFAP;
b) Column temperature. 80 °C;
c) Vaporization chamber temperature. 150 °C;
d) Testing room temperature. 150 °C;
e) Carrier gas (nitrogen) flow rate. 1 mL/min;
f) Split ratio. 10.1.
5.3 Reagents
5.3.1 Styrene. At 20 °C, the mass of 1.0 μL of gas is 0.9060 mg.
5.3.2 Standard gas. Use a microsyringe to accurately extract 1.0 μL of styrene, inject it
into a 100 mL airtight glass syringe, dilute it to 100.0 mL with clean air, and prepare
9.06 μg/mL standard gas. Or use a nationally recognized standard gas to prepare.
5.4 Sample collection, transportation and storage
5.4.1 On-site sampling shall be carried out in accordance with GBZ 159.
5.4.2 Short-time sampling. At the sampling point, use an activated carbon tube to collect
air samples at a flow rate of 100 mL/min for 15 minutes.
5.4.3 Long-term sampling. At the sampling point, use an activated carbon tube to collect
air samples at a flow rate of 50 mL/min for 2~8 hours.
5.4.4 After sampling, immediately seal both ends of the activated carbon tube and place
it in a clean container for transportation and storage. The sample can be stored in a
refrigerator for 14 days.
5.4.5 Sample blank. At the sampling point, open both ends of the activated carbon tube
and seal them immediately, then transport, store and measure together with the sample.
Each batch of samples shall have no less than 2 sample blanks.
5.5 Analysis steps
5.5.1 Sample treatment. Place the activated carbon tube in a thermal desorber, connect
the gas inlet to a 100 mL syringe and the other end to a carrier gas (nitrogen), and desorb
to 100.0 mL at 350 °C at a flow rate of 50 mL/min. The sample gas is used for
determination.
5.5.2 Preparation of the standard curve. Take 4~7 100 mL airtight glass syringes, inject
0.0 mL~10.0 mL of standard gas respectively, dilute with clean air to 100.0 mL, and
form a styrene standard series with a concentration range of 0.0 μg/mL~0.91 μg/mL.
Referring to the instrument operating conditions, adjust the gas chromatograph to the
optimal measurement state, inject 0.50 mL, and measure the peak height or peak area
of each concentration in the standard series. Draw a standard curve or calculate a
regression equation based on the measured peak heights or peak areas vs. the
corresponding styrene concentrations (μg/mL), and the correlation coefficient shall be
5.7.2 This method can also be used with other equivalent gas chromatographic columns.
Constant temperature measurement or programmed temperature measurement can be
selected according to the measurement requirements.
5.7.3 Styrene is easily adsorbed on the syringe wall and easily polymerized. The sample
shall be measured as soon as possible after desorption.
5.7.4 If the concentration of the analyte in the workplace air is high and penetration
may occur, two thermal desorption-activated carbon tubes shall be connected in series
for sampling.
6 Solvent desorption-gas chromatography of divinylbenzene
6.1 Principle
Vaporous divinylbenzene in the air is collected by activated carbon, desorbed by
acetone-carbon disulfide solution and then injected, separated by a gas chromatography
column and detected by a hydrogen flame ionization detector. The retention time is used
for qualitative analysis and the peak height or peak area is used for quantitative analysis.
6.2 Instruments
6.2.1 Activated carbon tube. solvent desorption type, containing 100 mg/50 mg of
activated carbon.
6.2.2 Air sampler. with a flow range of 0 mL/min～500 mL/min.
6.2.3 Solvent desorption bottle. 5 mL.
6.2.4 Microsyringe. 10 μL.
6.2.5 Gas chromatograph with a hydrogen flame ionization detector. Reference
operating conditions.
a) Chromatographic column. 30 m×0.32 mm×0.25 μm, 5%
phenylmethylsiloxane;
b) Column temperature. the initial temperature is 100°C; rise to 150 °C at
10 °C/min, and maintain for 3 min;
c) Vaporization chamber temperature. 200 °C;
d) Testing room temperature. 200 °C;
e) Carrier gas (nitrogen) flow rate. 1 mL/min;
f) Split ratio. 10.1.
6.3 Reagents
6.3.1 Desorption solution (acetone-carbon disulfide solution). Dilute 30 mL of acetone
to 100 mL with carbon disulfide. Chromatographic identification shows no interfering
peaks.
6.3.2 Standard solution. Add desorption solution to a volumetric flask, weigh accurately,
then add a certain amount of divinylbenzene, weigh accurately again, and adjust the
volume with the desorption solution. Calculate the concentration of the solution from
the difference between the two weighings, which is the standard stock solution and can
be stored in a refrigerator at 4 °C for 3 days. Before use, dilute with desorption solution
to a 2400.0 μg/mL divinylbenzene standard solution. Or prepare it with a nationally
recognized standard solution.
6.4 Sample collection, transportation and storage
6.4.1 On-site sampling shall be carried out in accordance with GBZ 159.
6.4.2 Short-time sampling. At the sampling point, use an activated carbon tube to collect
air samples at a flow rate of 200 mL/min for 15 min.
6.4.3 Long-term sampling. At the sampling point, use an activated carbon tube to collect
air samples at a flow rate of 50 mL/min for 2~8 hours.
6.4.4 After sampling, immediately seal both ends of the activated carbon tube and place
it in a clean container for transportation and storage. The sample can be stored at room
temperature for 7 days.
6.4.5 Sample blank. At the sampling point, open both ends of the activated carbon tube
and seal them immediately, then transport, store and measure together with the sample.
Each batch of samples shall have no less than 2 sample blanks.
6.5 Analysis steps
6.5.1 Sample treatment. Place the front and rear section activated carbon into two
solvent desorption bottles respectively, add 1.0 mL of desorption solution to each bottle,
seal it, desorb for 30 min, and shake it occasionally. The sample solution is for
determination.
6.5.2 Preparation of the standard curve. Take 4~7 volumetric flasks and dilute the
standard solution with desorption solution to form a divinylbenzene standard series with
a concentration range of 0.0 μg/mL~2400.0 μg/mL. Referring to the instrument
operating conditions, adjust the gas chromatograph to the optimal measurement state,
inject 1.0 μL, and measure the peak height or peak area of each concentration in the
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
Tips & Frequently Asked QuestionsQuestion 1: How long will the true-PDF of English version of GBZT300.68-2017 be delivered?Answer: The full copy PDF of English version of GBZT300.68-2017 can be downloaded in 9 seconds, and it will also be emailed to you in 9 seconds (double mechanisms to ensure the delivery reliably), with PDF-invoice. Question 2: Can I share the purchased PDF of GBZT300.68-2017_English with my colleagues?Answer: Yes. The purchased PDF of GBZT300.68-2017_English will be deemed to be sold to your employer/organization who actually paid for it, including your colleagues and your employer's intranet. Question 3: Does the price include tax/VAT?Answer: Yes. Our tax invoice, downloaded/delivered in 9 seconds, includes all tax/VAT and complies with 100+ countries' tax regulations (tax exempted in 100+ countries) -- See Avoidance of Double Taxation Agreements (DTAs): List of DTAs signed between Singapore and 100+ countriesQuestion 4: Do you accept my currency other than USD?Answer: Yes. www.ChineseStandard.us -- GBZT300.68-2017 -- Click this link and select your country/currency to pay, the exact amount in your currency will be printed on the invoice. Full PDF will also be downloaded/emailed in 9 seconds. How to buy and download a true PDF of English version of GBZT300.68-2017?A step-by-step guide to download PDF of GBZT300.68-2017_EnglishStep 1: Visit website https://www.ChineseStandard.net (Pay in USD), or https://www.ChineseStandard.us (Pay in any currencies such as Euro, KRW, JPY, AUD).
Step 2: Search keyword "GBZT300.68-2017".
Step 3: Click "Add to Cart". If multiple PDFs are required, repeat steps 2 and 3 to add up to 12 PDFs to cart.
Step 4: Select payment option (Via payment agents Stripe or PayPal).
Step 5: Customize Tax Invoice -- Fill up your email etc.
Step 6: Click "Checkout".
Step 7: Make payment by credit card, PayPal, Google Pay etc. After the payment is completed and in 9 seconds, you will receive 2 emails attached with the purchased PDFs and PDF-invoice, respectively.
Step 8: Optional -- Go to download PDF.
Step 9: Optional -- Click Open/Download PDF to download PDFs and invoice.
See screenshots for above steps: Steps 1~3 Steps 4~6 Step 7 Step 8 Step 9
|