On-line calculator AlcoDrinks on correct determination of volatile compounds, including ethanol, in alcohol products

Using this calculator, you can perform a quantitative determination of the content of volatile compounds, using ethanol as internal standard.

You should only specify the value of the area under the peaks of the analyzed compound and ethanol. As a result, you will immediately receive the concentration of analyzed compound in mg per liter of absolute alcohol (AA). Given values RRF ​​are approximate. For more accurate results, you should enter the improved values ​​for the calculation of RRF, corresponding to your gas chromatography.

Name of the sample:

*Densities are given according to TOXNET - Toxicology Data Network, U.S. National Library of Medicine http://toxnet.nlm.nih.gov/.
**Average coefficients RRF are calculated on results obtained on gas chromatographs Crystal (JSC SDB Chromatec, Yoshkar-Ola, Russia).

Determination of coefficients RRF

Values of coefficients RRF are calculated on experimental data of standard solutions with known values of concentration of volatile compounds by formula (4).

Table 1   Results of determination of coefficients RRF on experimental data presented in Figure 1
Compound Ci, mg/L (AA) Ai(1), arbitrary units (a.u.) Ai(2), arbitrary units (a.u.) RRFi(1) RRFi(2) RRFi(aver)
acetaldehyde 1093.7 2242.73 1928.25 1.357 1.316 1.337
methyl acetate 1051.1 2102.54 1762.88 1.391 1.384 1.387
ethyl acetate 1058.4 2628.58 2204.95 1.121 1.114 1.117
methanol 1119.1 2583.30 2092.81 1.206 1.241 1.223
2-propanol 1047.1 2990.90 2520.33 0.974 0.964 0.969
ethanol 789300 2196575 1831688 1.000 1.000 1.000
1-propanol 1029.0 4173.81 3553.94 0.686 0.672 0.679
isobutanol 1035.1 4910.14 4170.46 0.587 0.576 0.581
1-butanol 1042.8 4450.13 3764.17 0.652 0.643 0.648
isoamylol 1054.0 4621.50 3883.01 0.635 0.630 0.632
cyclohexanol 117.36 590.93 486.77 0.553 0.560 0.556
benzyl alcohol 1051.1 3218.04 2683.40 0.909 0.909 0.909
phenylethanol 1074.2 4100.24 3406.19 0.729 0.732 0.730

Determination of concentrations of volatile compounds in the alcohol-containing sample

Determination of concentrations of volatile compounds in test sample is performed in accordance with equation (3).

Table 2 Experimental data and data from certificate CRM LGC5100 Whisky - Congeners
Compound RRFi(aver) Ai(1),
arbitrary units (a.u.)
Ai(2),
arbitrary units (a.u.)
Ci(1),
mg/L (AA)
Ci(2),
mg/L (AA)
Ci(cp),
mg/L (AA)
Repr, % Ci(cert),
mg/L (AA)
Uncert, % Bias, %
acetaldehyde 1.337 32.132 30.300 75.35 76.34 75.84 1.3 - - -
methyl acetate 1.387 3.714 3.247 9.04 8.49 8.77 6.3 - - -
ethyl acetate 1.117 129.678 113.097 254.18 238.15 246.17 6.5 - - -
methanol 1.223 24.131 23.382 51.79 53.91 52.85 4.0 52.00 6.2 1.6
2-propanol 0.969 0.918 0.916 1.56 1.67 1.62 7.0 - - -
ethanol 1.000 449900 418776 789300 789300 789300 0.0 - - -
1-propanol 0.679 489.899 452.824 583.59 579.51 581.55 0.7 570.00 4.2 2.0
isobutanol 0.581 607.886 563.278 619.96 617.17 618.56 0.5 588.00 5.3 5.2
1-butanol 0.648 4.657 4.228 5.29 5.16 5.23 2.5 4.80 22.9 8.9
isoamylol 0.632 806.883 744.870 895.08 887.70 891.39 0.8 795.80 3.5 12.0

Peak area of analyzing volatile compounds are recorded in Table 2 in arbitrary units, for example, in "mV * min" or in "pA * s".

The bias between the values of the concentrations from the certificate and the experimentally measured are not more than 12.0% relative.

Fig. 1. An example of chromatograms of standard working solution of volatile compounds in ethanol.

Figure 1. An example of chromatograms of standard working solution of volatile compounds in ethanol.

Fig. 2. Chromatogram of the certified reference sample CRM LGC5100 Whisky - Congeners in logarithmic scale.

Figure 2. Chromatogram of the certified reference sample CRM LGC5100 Whisky - Congeners in a logarithmic scale.

Fig. 3. Chromatogram of the certified reference sample CRM LGC5100 Whisky - Congeners in linear scale.

Figure 3. Chromatogram of the certified reference sample CRM LGC5100 Whisky - Congeners in linear scale.

Fig. 4. Chromatogram of the second measurement of the sample CRM LGC5100 Whisky - Congeners.

Figure 4. Chromatogram of the second measurement of the sample CRM LGC5100 Whisky - Congeners.

References

  1. International Organization of Vine and Wine (OIV). Compendium of international methods of wine and must analysis, 2009; Vols. 1 and 2.
  2. Commission Regulation (EC) No 2870/2000 of 19 December 2000 laying down Community reference methods for the analysis of spirits drinks, 2000.
  3. AOAC (Association of Official Analytical Chemists) Official Methods 972.10. Alcohol (higher) and ethyl acetate in distilled liquors. Alternative gas chromatographic method, 1975.
  4. AOAC Official Methods 972.11. Methanol in distilled liquors. Gas chromatographic method, 1973.
  5. Charapitsa S.V. et al. Direct Determination of Volatile Compounds in Spirit Drinks by Gas Chromatography. J. Agricultural and Food Chemistry, 2013, 61 (12), 2950–2956 DOI:10.1021/jf3044956.
  6. Tables for determining of ethanol content in alcohol-water solutions (in Russian).

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