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R Partridge - One of the best experts on this subject based on the ideXlab platform.

  • study of the relative response factors of various gas chromatograph Flame Ionisation Detector systems for measurement of c2 c9 hydrocarbons in air
    Journal of Chromatography A, 2004
    Co-Authors: J Slemr, F Slemr, H Dsouza, R Partridge
    Abstract:

    Abstract The assumption of an instrument response that is linear with carbon number is frequently used to quantify atmospheric non-methane hydrocarbons (NMHCs) when using gas chromatography (GC) and detection by Flame Ionisation Detector (FID). In order to assess the validity of this widely used method the results of intercomparison measurements by 14 laboratories across Europe were evaluated. The intercomparison measurements were made on synthetic, gravimetrically-prepared, gas mixtures containing 30 hydrocarbons (C2–C9) in the low ppbv range, using various different GC–FID systems. The response per carbon atom of GC–FID systems to individual NMHCs, relative to that of butane, were found to differ by more than 25% across different systems. The differences were mostly caused by analytical errors within particular GC–FID systems and to a more minor degree by systematic deviations related to the molecular structure. (Correction factors due to the molecular structure would lessen the differences, e.g. by about 5% for olefin compounds.) The differences were larger than 10% even after elimination of obvious outliers. Thus, calibration of GC–FID systems with multicomponent NMHC mixtures is found to be essential whenever the accuracy of NMHC measurements is required to be better than about 10%. If calibration by multicomponent gas mixtures is not possible and effective carbon atom response factors are used to quantify the individual NMHC compounds then the particular analytical system should be carefully characterised and its responses to individual compounds be verified.

  • Study of the relative response factors of various gas chromatograph–Flame Ionisation Detector systems for measurement of C2–C9 hydrocarbons in air
    Journal of Chromatography A, 2004
    Co-Authors: J Slemr, F Slemr, H. D'souza, R Partridge
    Abstract:

    Abstract The assumption of an instrument response that is linear with carbon number is frequently used to quantify atmospheric non-methane hydrocarbons (NMHCs) when using gas chromatography (GC) and detection by Flame Ionisation Detector (FID). In order to assess the validity of this widely used method the results of intercomparison measurements by 14 laboratories across Europe were evaluated. The intercomparison measurements were made on synthetic, gravimetrically-prepared, gas mixtures containing 30 hydrocarbons (C2–C9) in the low ppbv range, using various different GC–FID systems. The response per carbon atom of GC–FID systems to individual NMHCs, relative to that of butane, were found to differ by more than 25% across different systems. The differences were mostly caused by analytical errors within particular GC–FID systems and to a more minor degree by systematic deviations related to the molecular structure. (Correction factors due to the molecular structure would lessen the differences, e.g. by about 5% for olefin compounds.) The differences were larger than 10% even after elimination of obvious outliers. Thus, calibration of GC–FID systems with multicomponent NMHC mixtures is found to be essential whenever the accuracy of NMHC measurements is required to be better than about 10%. If calibration by multicomponent gas mixtures is not possible and effective carbon atom response factors are used to quantify the individual NMHC compounds then the particular analytical system should be carefully characterised and its responses to individual compounds be verified.

J Slemr - One of the best experts on this subject based on the ideXlab platform.

  • study of the relative response factors of various gas chromatograph Flame Ionisation Detector systems for measurement of c2 c9 hydrocarbons in air
    Journal of Chromatography A, 2004
    Co-Authors: J Slemr, F Slemr, H Dsouza, R Partridge
    Abstract:

    Abstract The assumption of an instrument response that is linear with carbon number is frequently used to quantify atmospheric non-methane hydrocarbons (NMHCs) when using gas chromatography (GC) and detection by Flame Ionisation Detector (FID). In order to assess the validity of this widely used method the results of intercomparison measurements by 14 laboratories across Europe were evaluated. The intercomparison measurements were made on synthetic, gravimetrically-prepared, gas mixtures containing 30 hydrocarbons (C2–C9) in the low ppbv range, using various different GC–FID systems. The response per carbon atom of GC–FID systems to individual NMHCs, relative to that of butane, were found to differ by more than 25% across different systems. The differences were mostly caused by analytical errors within particular GC–FID systems and to a more minor degree by systematic deviations related to the molecular structure. (Correction factors due to the molecular structure would lessen the differences, e.g. by about 5% for olefin compounds.) The differences were larger than 10% even after elimination of obvious outliers. Thus, calibration of GC–FID systems with multicomponent NMHC mixtures is found to be essential whenever the accuracy of NMHC measurements is required to be better than about 10%. If calibration by multicomponent gas mixtures is not possible and effective carbon atom response factors are used to quantify the individual NMHC compounds then the particular analytical system should be carefully characterised and its responses to individual compounds be verified.

  • Study of the relative response factors of various gas chromatograph–Flame Ionisation Detector systems for measurement of C2–C9 hydrocarbons in air
    Journal of Chromatography A, 2004
    Co-Authors: J Slemr, F Slemr, H. D'souza, R Partridge
    Abstract:

    Abstract The assumption of an instrument response that is linear with carbon number is frequently used to quantify atmospheric non-methane hydrocarbons (NMHCs) when using gas chromatography (GC) and detection by Flame Ionisation Detector (FID). In order to assess the validity of this widely used method the results of intercomparison measurements by 14 laboratories across Europe were evaluated. The intercomparison measurements were made on synthetic, gravimetrically-prepared, gas mixtures containing 30 hydrocarbons (C2–C9) in the low ppbv range, using various different GC–FID systems. The response per carbon atom of GC–FID systems to individual NMHCs, relative to that of butane, were found to differ by more than 25% across different systems. The differences were mostly caused by analytical errors within particular GC–FID systems and to a more minor degree by systematic deviations related to the molecular structure. (Correction factors due to the molecular structure would lessen the differences, e.g. by about 5% for olefin compounds.) The differences were larger than 10% even after elimination of obvious outliers. Thus, calibration of GC–FID systems with multicomponent NMHC mixtures is found to be essential whenever the accuracy of NMHC measurements is required to be better than about 10%. If calibration by multicomponent gas mixtures is not possible and effective carbon atom response factors are used to quantify the individual NMHC compounds then the particular analytical system should be carefully characterised and its responses to individual compounds be verified.

P. C. Chatwin - One of the best experts on this subject based on the ideXlab platform.

  • Fluctuations in dense gas concentrations measured in a wind-tunnel
    Boundary-Layer Meteorology, 1995
    Co-Authors: William B. Zimmerman, P. C. Chatwin
    Abstract:

    Concentration time series from FID (Flame Ionisation Detector) sensors and catharometers downstream of an instantaneous release of dense gas contaminants are analysed by statistical methods. For each experiment there are either 50 or 100 replications, thus allowing estimates of statistical properties to be made even though the dispersion is nonstationary. The time history of the first four central moments is estimated, and they are plotted against each other, in the manner suggested by Mole and Clarke (1995). The collapse of the skewness-kurtosis plot onto a universal quadratic curve, similar to that found by Mole and Clarke for continuous releases, is observed. In this paper, we show how this observation is consistent with the form of the pdf postulated by Chatwin and Sullivan (1989).

F Slemr - One of the best experts on this subject based on the ideXlab platform.

  • study of the relative response factors of various gas chromatograph Flame Ionisation Detector systems for measurement of c2 c9 hydrocarbons in air
    Journal of Chromatography A, 2004
    Co-Authors: J Slemr, F Slemr, H Dsouza, R Partridge
    Abstract:

    Abstract The assumption of an instrument response that is linear with carbon number is frequently used to quantify atmospheric non-methane hydrocarbons (NMHCs) when using gas chromatography (GC) and detection by Flame Ionisation Detector (FID). In order to assess the validity of this widely used method the results of intercomparison measurements by 14 laboratories across Europe were evaluated. The intercomparison measurements were made on synthetic, gravimetrically-prepared, gas mixtures containing 30 hydrocarbons (C2–C9) in the low ppbv range, using various different GC–FID systems. The response per carbon atom of GC–FID systems to individual NMHCs, relative to that of butane, were found to differ by more than 25% across different systems. The differences were mostly caused by analytical errors within particular GC–FID systems and to a more minor degree by systematic deviations related to the molecular structure. (Correction factors due to the molecular structure would lessen the differences, e.g. by about 5% for olefin compounds.) The differences were larger than 10% even after elimination of obvious outliers. Thus, calibration of GC–FID systems with multicomponent NMHC mixtures is found to be essential whenever the accuracy of NMHC measurements is required to be better than about 10%. If calibration by multicomponent gas mixtures is not possible and effective carbon atom response factors are used to quantify the individual NMHC compounds then the particular analytical system should be carefully characterised and its responses to individual compounds be verified.

  • Study of the relative response factors of various gas chromatograph–Flame Ionisation Detector systems for measurement of C2–C9 hydrocarbons in air
    Journal of Chromatography A, 2004
    Co-Authors: J Slemr, F Slemr, H. D'souza, R Partridge
    Abstract:

    Abstract The assumption of an instrument response that is linear with carbon number is frequently used to quantify atmospheric non-methane hydrocarbons (NMHCs) when using gas chromatography (GC) and detection by Flame Ionisation Detector (FID). In order to assess the validity of this widely used method the results of intercomparison measurements by 14 laboratories across Europe were evaluated. The intercomparison measurements were made on synthetic, gravimetrically-prepared, gas mixtures containing 30 hydrocarbons (C2–C9) in the low ppbv range, using various different GC–FID systems. The response per carbon atom of GC–FID systems to individual NMHCs, relative to that of butane, were found to differ by more than 25% across different systems. The differences were mostly caused by analytical errors within particular GC–FID systems and to a more minor degree by systematic deviations related to the molecular structure. (Correction factors due to the molecular structure would lessen the differences, e.g. by about 5% for olefin compounds.) The differences were larger than 10% even after elimination of obvious outliers. Thus, calibration of GC–FID systems with multicomponent NMHC mixtures is found to be essential whenever the accuracy of NMHC measurements is required to be better than about 10%. If calibration by multicomponent gas mixtures is not possible and effective carbon atom response factors are used to quantify the individual NMHC compounds then the particular analytical system should be carefully characterised and its responses to individual compounds be verified.

Gaofei Hu - One of the best experts on this subject based on the ideXlab platform.

  • an efficient method for the simultaneous determination of furan 2 methylfuran and 2 pentylfuran in fruit juices by headspace solid phase microextraction and gas chromatography Flame Ionisation Detector
    Food Chemistry, 2016
    Co-Authors: Gaofei Hu, Marta Hernandez, Tatiana Koutchma, Suqin Shao
    Abstract:

    Abstract A headspace solid phase microextraction (HS-SPME) procedure followed by gas chromatography–Flame Ionisation Detector (GC–FID) analysis was developed and validated for the simultaneous analysis of furan, 2-methylfuran and 2-pentylfuran from juice samples. Extraction at 32 °C for 20 min with stirring at 600 rpm and NaCl concentration 15% (W/V) was the optimal HS-SPME condition for all the three compounds by using a carboxen/polydimethylsiloxane fused silica fibre (75 μm). The extracted compounds were base line separated on a SPB-1 GC column within 12 min. The relative standard deviations of all analytes were less than 6.7%. The recovery rates were between 90.2% and 110.1%. The limits of detection and limits of quantification were 0.056–0.23 ng/mL and 0.14–0.76 ng/mL, respectively. The results showed that the developed method was sensitive, precise, accurate and robust for the determination of furan, 2-methylfuran and 2-pentylfuran in complex matrices without interferences from other components.