scholarly journals Method for determination of stable carbon isotope ratio of methylnitrophenols in atmospheric particulate matter

2011 ◽  
Vol 4 (11) ◽  
pp. 2453-2464 ◽  
Author(s):  
S. Moukhtar ◽  
M. Saccon ◽  
A. Kornilova ◽  
S. Irei ◽  
L. Huang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Particulate Matter ◽  
Stable Isotope ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Stable Carbon Isotope ◽  
Atmospheric Particulate Matter ◽  
Stable Carbon ◽  
Atmospheric Particulate

Abstract. A technique for the measurement of the stable isotope ratio of methylnitrophenols in atmospheric particulate matter is presented. Atmospheric samples from rural and suburban areas were collected for evaluation of the procedure. Particulate matter was collected on quartz fibre filters using dichotomous high volume air samplers. Methylnitrophenols were extracted from the filters using acetonitrile. The sample was then purified using a combination of high-performance liquid chromatography and solid phase extraction. The final solution was then divided into two aliquots. To one aliquot, a derivatising agent, Bis(trimethylsilyl)trifluoroacetamide, was added for Gas Chromatography-Mass Spectrometry analysis. The second half of the sample was stored in a refrigerator. For samples with concentrations exceeding 1 ng μl−1, the second half of the sample was used for measurement of stable carbon isotope ratios by Gas Chromatography-Isotope Ratio Mass Spectrometry. The procedure described in this paper provides a method for the analysis of methylnitrophenols in atmospheric particulate matter at concentrations as low as 0.3 pg m−3 and for stable isotope ratios with an accuracy of better than ±0.5‰ for concentrations exceeding 100 pg m−3. In all atmospheric particulate matter samples analysed, 2-methyl-4-nitrophenol was found to be the most abundant methylnitrophenol, with concentrations ranging from the low pg m−3 range in rural areas to more than 200 pg m−3 in some samples from a suburban location.

scholarly journals Method for determination of stable carbon isotope ratio of methylnitrophenols in atmospheric PM

2011 ◽  
Vol 4 (3) ◽  
pp. 3199-3231
Author(s):  
S. Moukhtar ◽  
M. Saccon ◽  
A. Kornilova ◽  
S. Irei ◽  
L. Huang ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Stable Isotope ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Solid Phase ◽  
Stable Carbon Isotope ◽  
Stable Isotope Ratio ◽  
Atmospheric Particulate Matter ◽  
Stable Carbon ◽  
Ms Analysis

Abstract. A technique for the measurement of the stable isotope ratio of methylnitrophenols in atmospheric particulate matter (PM) is presented. It has been found in numerous laboratory studies that these compounds are photooxidation products of toluene in PM. Atmospheric samples from rural and suburban areas were collected for evaluation of the procedure. PM was collected on quartz fibre filters using dichotomous high volume air samplers for PM 2.5. Methylnitrophenols were extracted from the filters using acetonitrile. The sample was then purified using a combination of high-performance liquid chromatography (HPLC) and solid phase extraction (SPE). The final solution was then divided into two aliquots. To one aliquot, a derivatising agent, Bis(trimethylsilyl)trifluoroacetamide (BSTFA), was added to the solution for Gas Chromatography/Mass Spectroscopy (GC/MS) analysis. The second half of the sample was stored at low temperature. When GC/MS analysis showed high enough concentrations the remaining sample was derivatized with BSTFA and analysed for stable isotope ratio using a Gas Chromatography/Isotope Ratio Mass Spectrometry (GC-IRMS). In all atmospheric PM samples analysed, 2-methyl-4-nitrophenol was found to be the most abundant methylnitrophenol. Nevertheless, due to low pollution levels occurring in the rural area, no samples had concentrations high enough to perform stable carbon isotope composition measurements of the methylnitrophenols. Samples collected in the suburban area could be analysed for carbon stable isotope ratio using GC-IRMS. The procedure described in this paper provides a very sensitive and selective method for the analysis of methylnitrophenols in atmospheric PM at concentrations as low as 1 pg m−3. For accurate (within ±0.5‰) stable isotope ratio analysis significantly higher concentrations in the range of 100 pg m−3 or more are required.

scholarly journals Biomarker Ratios and Stablecarbon Isotopes to Describe Crude Oils Characteristics in the Murzuq Basin (Libya)

2019 ◽  
pp. 1-12
Author(s):  
S. Aboglila ◽  
A. Abdulgader ◽  
A. Albaghdady ◽  
O. Hlal ◽  
E. Farifr
Keyword(s):  
Mass Spectrometry ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Stable Carbon Isotope ◽  
Source Rocks ◽  
Bacterial Degradation ◽  
Gas Chromatography Mass Spectrometry ◽  
Crude Oils ◽  
Stable Carbon ◽  
Lower Palaeozoic

This present paper includes a detailed evaluation of specific biomarkers together with stable carbon isotope (δ13C) by gas chromatography-mass spectrometry (GC–MS) and Gas Chromatograph–Isotope Ratio Mass Spectrometry (GC–IR–MS). Eight crude oil samples were collected from the A, B, H (east) and H (west) Fields, located in the Murzuq Basin, Libya. Stable Carbon isotope data (δ13C) together with biomarker ratios data of individual hydrocarbons, n-alkanes, isoprenoids, terpenes, hopanes, steranes and aromatic have been determined in crude oils to delineate their bacterial degradation, source facies, organic matter precursors, depositional conditions and a variation of maturation. Based on source-specific parameters including n-C19 alkane, % C27S, %C28S, %C29S, %C23TT, %C30αβ, %rC28, DBT/P, CPI, Pr/Ph, Ts/Tm, dh 30/h 30, 1 MN, 2 MN,         26-27 DMN, 15 DMN, 236 TMN, 146-135 TMN, 125 TMN, 136 TMN ratios and δ13C‰ of saturates and aromatics fractions. Such oils showed non-biodegradation, n-C19 peak proved oils generated from a Lower Palaeozoic source rocks as emphasizedvian-C19 peak, the dominance of C29steranes over C27 and C28 with light Carbon isotope ratio (δ13C‰) values. The abundances of isosterane C29, C27, C28.Tricyclohexaprenol and bacteriohopane polyols and aminopolyols, recommended as mixture bioprecursors of tricyclic terpenes and hopanes, furthermore regular sterane ratio gives values characteristic of Lower Palaeozoic marine source rocks and holding green algae and most likely a quantity of contribution from acritarchs. Carbon preference indices (CPIs)>0.9 pointed to an anoxic deposition, dibenzothiophene to phenanthrene (DBT/Prange 0.49 - 0.58) recommend a siliciclastic source rather than carbonate and/or evaporate saline deposition. The ratios of CPIs, pristane/n-C17 and phytane/n-C18, n-alkanes (C16 to C22) against (C23 to C33), Ts/Tm, C30diahopane/C30hopane, methylnaphthalene, dimethyl naphthalene and trimethyl naphthalene indicated that the oils analysed are mature except the B Field oil being slightly less mature than the A, H (east) and  H (west) Fields oils.

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