General knowledge of coatings: Determination of VOC in waterborne coatings by gas chromatography

Core tip: 0 Preface With the increasing attention to indoor environmental protection quality, the content of volatile organic compounds (VOC) in the interior decoration materials - water-based coatings is widely concerned Although in HJ / t201-2005 "technical requirements for environmental labeling products - waterborne coatings", the definition of VOC is defined and the determination method is standardized However, the standard does not make clear provisions for some operation details, which results in the fact that in the actual production, when the inspectors test VOC according to the above standards, such as operation Paint knowledge how about Akzo Nobel Powder Coating Recommended introduction: powder coating is a kind of coating with different form from general coating, which is in powder form It is a new type of coating, because of its own advantages and more and more known by people Let's introduce Akzo Nobel Powder coating Akzo Nobel Powder coating is a cost-effective coating solution, which can be applied to different kinds of products After the treatment of static electricity and fire baking, a tough and durable coating surface will be formed, with the least impact on the environment Since the introduction of this technology, powder coating has been able to continue to maintain the With the increasing attention to the indoor environmental protection quality, the content of volatile organic compounds (VOC) in the indoor decoration materials - water-based coatings has been widely concerned Although in HJ / t201-2005 "technical requirements for environmental labeling products - waterborne coatings", the definition of VOC is defined and the determination method is standardized However, the standard does not make clear provisions for some operation details, resulting in problems such as difficult operation, long detection cycle and so on when the inspectors detect VOC according to the above standards in actual production This paper discusses how to solve these problems 1 Principle of test part 1.1 this method is based on the definition of VOC in the boiling point of 250 ℃, using direct injection gas chromatography with FID detector to determine the mass fraction of VOC in waterborne coatings A portion of the coating sample is dissolved in a suitable solvent containing a known amount of internal standard (diethyl adipate, DEA) The resulting solution is injected into a gas chromatograph for quantification In this method, 6% nitrile propyl phenyl / 94% dimethylpolysiloxane coated capillary column (rtx-1301) is used as the basic column, diethyl adipate (DEA) is used as both internal standard and boiling point marker at 250 ℃ to distinguish VOC and non VOC substances in paint samples The substances that peak before DEA are classified as VOC, while the substances that peak after DEA are classified as non VOC The qualitative analysis of VOC is completed by the database of retention time of known substances on the basic column (the database of our laboratory); the quantitative analysis of VOC is completed by using their corresponding response factors on the FID detector The response factor of DEA is used to quantify the known or unknown VOC with small peak value and no reference material to establish the relative response factor The total VOC mass fraction is calculated by adding all the detected VOC mass fractions 1.2 instrument and reagent 1.2.1 instrument agilent-6890; capillary column rxt-1301 (J & W), 60m × 0.32mm inner diameter × 1.0 μ m film thickness; recorder: Agilent 6890 workstation; microinjector: 5.0 μ L; corked glass bottle: 10ml 1.2.2 reagent acetonitrile, diethyl adipate, ethylene glycol, 1,2-propanediol, diethylene glycol monobutyl ether, ethylene glycol propylene ether, all of which are analytical pure; sample, interior wall latex coating 1.3 determination method 1.3.1 operation conditions of the instrument carrier gas type: nitrogen (N2) column head pressure: 9psi (normal pressure mode) column flow rate: 0.77ml/min line speed: 15.3cm/s injector: shunt, 250 ℃ shunt rate: 40 injection volume: 2.0 μ l detector: flame ion detector (FID), 250 ℃ detector gas flow rate: H2, 45ml / min; air, 500ml / min; Tail blowing: 50ml / min gas chromatograph oven temperature program: initial temperature: 100 ℃ initial time: 1min heating rate: 20 ℃ / min final temperature: 250 ℃ final time: 21min complete operation time: 29.5min paint home is focused on coating, diatom mud, paint coating, coating process, fire retardant coating news and coating, diatom mud, paint coating, coating process, Decoration knowledge and effect drawing of fireproof coating,