Method to predict gas chromatographic response factors for the trace-level analysis of volatile organic compounds based on the effective carbon number concept

2013 ◽  
Vol 36 (20) ◽  
pp. 3356-3365 ◽  
Author(s):  
Jan E. Szulejko ◽  
Yong-Hyun Kim ◽  
Ki-Hyun Kim
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Carbon Number ◽  
Trace Level ◽  
Response Factors ◽  
Number Concept ◽  
Volatile Organic ◽  
Level Analysis

scholarly journals Zeolite based microconcentrators for volatile organic compounds sensing at trace-level: fabrication and performance

2016 ◽  
Vol 26 (8) ◽  
pp. 084010 ◽  
Author(s):  
Fernando Almazán ◽  
Ismael Pellejero ◽  
Alberto Morales ◽  
Miguel A Urbiztondo ◽  
Javier Sesé ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Trace Level ◽  
Volatile Organic ◽  
And Performance

scholarly journals Chemical characterisation of benzene oxidation products under high- and low-NO<sub><i>x</i></sub> conditions using chemical ionisation mass spectrometry

2021 ◽  
Vol 21 (5) ◽  
pp. 3473-3490
Author(s):  
Michael Priestley ◽  
Thomas J. Bannan ◽  
Michael Le Breton ◽  
Stephen D. Worrall ◽  
Sungah Kang ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
First Generation ◽  
Carbon Number ◽  
Oxidation Products ◽  
Benzene Oxidation ◽  
Volatile Organic ◽  
Cluster 2 ◽  
Chemical Ionisation ◽  
Ionisation Mass

Abstract. Aromatic hydrocarbons are a class of volatile organic compounds associated with anthropogenic activity and make up a significant fraction of urban volatile organic compound (VOC) emissions that contribute to the formation of secondary organic aerosol (SOA). Benzene is one of the most abundant species emitted from vehicles, biomass burning and industry. An iodide time-of-flight chemical ionisation mass spectrometer (ToF-CIMS) and nitrate ToF-CIMS were deployed at the Jülich Plant Atmosphere Chamber as part of a series of experiments examining benzene oxidation by OH under high- and low-NOx conditions, where a range of organic oxidation products were detected. The nitrate scheme detects many oxidation products with high masses, ranging from intermediate volatile organic compounds (IVOCs) to extremely low volatile organic compounds (ELVOCs), including C12 dimers. In comparison, very few species with C≥6 and O≥8 were detected with the iodide scheme, which detected many more IVOCs and semi-volatile organic compounds (SVOCs) but very few ELVOCs and low volatile organic compounds (LVOCs). A total of 132 and 195 CHO and CHON oxidation products are detected by the iodide ToF-CIMS in the low- and high-NOx experiments respectively. Ring-breaking products make up the dominant fraction of detected signal and 21 and 26 of the products listed in the Master Chemical Mechanism (MCM) were detected. The time series of highly oxidised (O≥6) and ring-retaining oxidation products (C6 and double-bond equivalent = 4) equilibrate quickly, characterised by a square form profile, compared to MCM and ring-breaking products which increase throughout oxidation, exhibiting sawtooth profiles. Under low-NOx conditions, all CHO formulae attributed to radical termination reactions of first-generation benzene products, and first-generation auto-oxidation products are observed. Several N-containing species that are either first-generation benzene products or first-generation auto-oxidation products are also observed under high-NOx conditions. Hierarchical cluster analysis finds four clusters, of which two describe photo-oxidation. Cluster 2 shows a negative dependency on the NO2/NOx ratio, indicating it is sensitive to NO concentration and thus likely to contain NO addition products and alkoxy-derived termination products. This cluster has the highest average carbon oxidation state (OSC‾) and the lowest average carbon number. Where nitrogen is present in a cluster member of cluster 2, the oxygen number is even, as expected for alkoxy-derived products. In contrast, cluster 1 shows no dependency on the NO2/NOx ratio and so is likely to contain more NO2 addition and peroxy-derived termination products. This cluster contains fewer fragmented species, as the average carbon number is higher and OSC‾ lower than cluster 2, and more species with an odd number of oxygen atoms. This suggests that clustering of time series which have features pertaining to distinct chemical regimes, for example, NO2/NOx perturbations, coupled with a priori knowledge, can provide insight into identification of potential functionality.

scholarly journals On-Road Emission Characteristics of Volatile Organic Compounds from Light-Duty Diesel Trucks Meeting Different Emission Standards

2020 ◽  
Author(s):  
Menglei Wang ◽  
Rencheng Zhu ◽  
Ruiqin Zhang ◽  
Shunyi Li ◽  
Xiaofeng Bao
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Carbon Number ◽  
Decision Makers ◽  
Emission Characteristics ◽  
Ozone Formation ◽  
Voc Emissions ◽  
Light Duty ◽  
Volatile Organic ◽  
Diesel Trucks

On-road tailpipe volatile organic compounds (VOCs) were sampled from light-duty diesel trucks compliant with Euro III to V, and a total of 102 VOC species were quantified. The composition characteristics and carbon number distributions were investigated, and the contribution of individual VOC to ozone formation potentials (OFPs) was weighted. Results showed that alkanes were the major VOC species, accounting for approximately 65.5%. VOC emissions decreased significantly as the standards became stricter, especially for alkanes and aromatics; and the VOC emissions on highway were much lower than those on urban roads. Carbon number distribution of VOCs was mainly concentrated in C3-C4 and C10-C12. Aromatics were the major contributors to ozone formation, taking up 49.3-57.6% of the total OFPs, and naphthalene, 1-butene, dodecane, 1,2,3-trimethylbenzene and 2-propenal were the top five species. The information provided insight into the tailpipe VOC emission characteristics, and may help decision makers drafting related emission policies.

scholarly journals Quantification of biogenic volatile organic compounds with a flame ionization detector using the effective carbon number concept

2012 ◽  
Vol 5 (8) ◽  
pp. 1911-1923 ◽  
Author(s):  
C. L. Faiola ◽  
M. H. Erickson ◽  
V. L. Fricaud ◽  
B. T. Jobson ◽  
T. M. VanReken
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Chromatographic Analysis ◽  
Carbon Number ◽  
Flame Ionization Detector ◽  
Biogenic Volatile Organic Compounds ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Volatile Organic ◽  
The Difference

Abstract. Biogenic volatile organic compounds (BVOCs) are emitted into the atmosphere by plants and include isoprene, monoterpenes, sesquiterpenes, and their oxygenated derivatives. These BVOCs are among the principal factors influencing the oxidative capacity of the atmosphere in forested regions. BVOC emission rates are often measured by collecting samples onto adsorptive cartridges in the field and then transporting these samples to the laboratory for chromatographic analysis. One of the most commonly used detectors in chromatographic analysis is the flame ionization detector (FID). For quantitative analysis with an FID, relative response factors may be estimated using the effective carbon number (ECN) concept. The purpose of this study was to determine the ECN for a variety of terpenoid compounds to enable improved quantification of BVOC measurements. A dynamic dilution system was developed to make quantitative gas standards of VOCs with mixing ratios from 20–55 ppb. For each experiment using this system, one terpene standard was co-injected with an internal reference, n-octane, and analyzed via an automated cryofocusing system interfaced to a gas chromatograph flame ionization detector and mass spectrometer (GC/MS/FID). The ECNs of 16 compounds (14 BVOCs) were evaluated with this approach, with each test compound analyzed at least three times. The difference between the actual carbon number and measured ECN ranged from −24% to −2%. The difference between theoretical ECN and measured ECN ranged from −22% to 9%. Measured ECN values were within 10% of theoretical ECN values for most terpenoid compounds.

scholarly journals Chemical characterisation of benzene oxidation products under high and low NO<sub>x</sub> conditions using chemical ionisation mass spectrometry

2020 ◽  
Author(s):  
Michael Priestley ◽  
Thomas J. Bannan ◽  
Michael Le Breton ◽  
Stephen D. Worrall ◽  
Sungah Kang ◽  
...  
Keyword(s):  
Time Series ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Carbon Number ◽  
Oxidation Products ◽  
Benzene Oxidation ◽  
Volatile Organic ◽  
Cluster 2 ◽  
Chemical Ionisation ◽  
Ionisation Mass

Abstract. Aromatic hydrocarbons are a class of volatile organic compounds associated with anthropogenic activity and make up a significant fraction of urban VOC emissions that contribute to the formation of secondary organic aerosol (SOA). Benzene is one of the most abundant species emitted from vehicles, biomass burning and industry. An iodide time of flight chemical ionisation mass spectrometer (ToF-CIMS) and nitrate ToF-CIMS were deployed at the Jülich plant chamber as part of a series of experiments examining benzene oxidation by OH under high and low NOx conditions, where a range of organic oxidation products were detected. The nitrate scheme detects many oxidation products with high masses ranging from intermediate volatile organic compounds (IVOC) to extremely low volatile organic compounds (ELVOC), including C12 dimers. In comparison, very few species with C≥6 and O≥8 were detected with the iodide scheme, which detected many more IVOC and semi volatile organic compounds (SVOC) but very few ELVOC and low volatile organic compounds (LVOC). 132 and 195 CHO and CHON oxidation products are detected by the iodide ToF-CIMS in the low and high NOx experiments respectively. Ring breaking products make up the dominant fraction of detected signal (89–91 %). 21 and 26 of the products listed in the master chemical mechanism (MCM) were detected and account for 6.4–7.3 % of total signal. The time series of highly oxidised (O≥6) and ring retaining oxidation products (C6 and double bond equivalent = 4) equilibrate quickly characterised by a square form profile, compared to MCM and ring breaking products which increase throughout oxidation exhibiting saw tooth profiles. Under low NOx conditions, all CHO formulae attributed to radical termination reactions of 1st generation benzene products and 1st generation autoxidation products are observed, and one exclusively 2nd generation autoxidation product is also measured (C6H8O8). Several N containing species that are either 1st generation benzene products or 1st generation autoxidation products are also observed under high NOx conditions. Hierarchical cluster analysis finds four cluster of which two describe photo-oxidation. Cluster 2 shows a negative dependency on the NO2/NOx ratio indicating it is sensitive to NO concentration thus likely to contain NO addition products and alkoxy derived termination products. This cluster has the highest average carbon oxidation state (OSc) and the lowest average carbon number and where nitrogen is present in cluster member, the oxygen number is even, as expected for alkoxy derived products. In contrast, cluster 1 shows no dependency on the NO2/NOx ratio and so is likely to contain more NO2 addition and peroxy derived termination products. This cluster contains less fragmented species, as the average carbon number is higher and OSc lower than cluster 2, and more species with an odd number of oxygen atoms. This suggests clustering of time series which have features pertaining to distinct chemical regimes e.g. NO2/NOx perturbations, coupled with a priori knowledge, can provide insight into identification of potential functionality.

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