IOFI recommended practice for the use of predicted relative‐response factors for the rapid quantification of volatile flavouring compounds by GC‐FID

Abstract

This recommended practice enables the quantification of volatile compounds in flavourings to be made by gas chromatography with flame-ionization detection, without having authentic compounds available, and also in many cases it can avoid time-consuming calibration procedures. The relative-response factors (RRF) can be predicted from the molecular formula of the compound, and this approach can be applied to compounds containing the atoms C, H, O, N, S, F, Cl, Br, I, and Si, providing that the molecular formula and number of benzene rings in the analytes are known. The purity of chemicallydefined flavouring substances or chromatographic standards can also be estimated using these predicted RRF, and this procedure can also be used to quantify (poly)hydroxylated compounds, after their derivatization into trimethylsilyl ethers or esters.

Chemical characterization and in vitro antioxidant and antimicrobial activities of essential oil from Commiphora wildii Merxm. (omumbiri) resin

“…The values used in the formula above were calculated using the formula:where is the measured RRF of each of the ISTDs relative to MO and is the predicted RRF of sample constituent i relative to MO. The latter values were calculated for each sample constituent based on their molecular formulae (see Appendix S1) . For the determination of the values, solutions of decane (1.49 mg mL –1 ) and 3‐carene (4.32 mg mL –1 ) were prepared at 50, 100, and 150% levels of the specified concentrations, and each solution contained MO (4.36 mg mL –1 ) as the internal standard.…”

“…Next, the RRFs of the remaining sample constituents were predicted relative to methyl octanoate (MO), as described by Cachet et al 15 For this purpose the RRFs of decane and 3-carene were experimentally determined relative to MO. Hence the mass of each sample constituent present in the sample could be calculated using the formula:…”

“…The latter values were calculated for each sample constituent based on their molecular formulae (see Appendix S1). 15,16 For the determination of the RRF Meas ISTD∕MO values, solutions of decane (1.49 mg mL -1 ) and 3-carene (4.32 mg mL -1 ) were prepared at 50, 100, and 150% levels of the specified concentrations, and each solution contained MO (4.36 mg mL -1 ) as the internal standard.…”

Comparison of composition of volatile compounds in ten Salvia species isolated by different methods

“…without using ISTD and without calculating response factors for the individual compounds. The shortcomings of such data handling as well as the recommendations for obtaining more reliable data on volatiles were prepared few years ago by a group of experts . Data handling in our study is based on the above‐mentioned recommendations and the concentration of volatiles is expressed in mg per kg of DWP.…”

“…A split/splitless injector was used at 260°C in a split mode at a ratio of 1:10; the injection volume was 1 μL. Quantitative data were calculated according to Cachet et al , using the formula: , where m i is the mass of the compound i to be quantified, expressed in mg in kg of plant dry weight (DWP); ‐ predicted relative response factor of compound i , m D – mass of decane (internal standard, ISTD), A i and A D – are the peak area of the analyte and the ISTD, respectively. The response factor relative to decane has been recalculated from RRF of methyl octanoate (MO) by taking into account the corrective factor of RRF decane/MO of 0.726.…”