A method of assessing at least one polymer composition including contaminants comprising the steps of (a) carrying out an advanced odorant analysis using comprehensive two-dimensional gas chromatography (GCxGC) coupled to time-of-flight mass spectrometry (TOF-MS) (b) calculating a toluene response factor as RF toluene = m toluene μg Peak area toluene as the arithmetic mean response factor from individual calibration runs, (c) semi-quantifying the odorant amount per substance by multiplying the toluene's average response factor by the peak area of the odorant from the sample analysis run following OA μg = RF toluene ∗ peak area odorant (d) calculating the odorants index, whereby the odorants index is defined as the ratio of two groups of the before semi-quantitatively determined substances according to Odorants Index OI = ASSA + SMUSA + SST + SFFA + SOSO SSA whereby - adjusted sum of saturated n-aldehydes (ASSA) is defined as: ASSA = SSA ∗ AF where the sum of saturated n-aldehydes in the carbon number range of C6-C10 (hexanal, heptanal, octanal, nonanal, decanal) is defined as: SSA = OA hexanal + OA heptanal + OA octanal + OA nonanal + OA decanal and the aldehyde factor is defined as: AF = 1 + SSA ∗ e SSA ∗ 15 - SMUSA stands for sum of mono-unsaturated n-aldehydes (SMUSA): -2-heptenal and -2-nonenal: SMUSA = OA Z − 2 − heptenal + OA Z − 2 − nonenal - SST stands for sum of selected terpenes: D-limonene and eucalyptol: SST = OA D − limonene + OA eucalyptol - SFFA stands for sum of free fatty acids (SFFA) with carbon numbers of C2, C4, C6, C8, C10 (acetic acid, butanoic acid, hexanoic acid, octanoic acid, decanoic acid): SFFA = OA acetic acid + OA butanoic acid + OA hexanoic acid + OA octanoic acid + OA decanoic acid and - SOSO stands for sum of styrene and acetophenone: SOSO = OA styrene + OA acetophenone and - SSA stands for the total amount of saturated aldehydes in the range of C6-C10 (Sum of saturated aldehydes, SSA) but without a factor: SSA = OA hexanal + OA heptanal + OA octanal + OA nonanal + OA decanal (e) setting aside any polymer composition having an odorants index above 1.50. (a) carrying out an advanced odorant analysis using comprehensive two-dimensional gas chromatography (GCxGC) coupled to time-of-flight mass spectrometry (TOF-MS) (b) calculating a toluene response factor as RF toluene = m toluene μg Peak area toluene as the arithmetic mean response factor from individual calibration runs, (c) semi-quantifying the odorant amount per substance by multiplying the toluene's average response factor by the peak area of the odorant from the sample analysis run following OA μg = RF toluene ∗ peak area odorant (d) calculating the odorants index, whereby the odorants index is defined as the ratio of two groups of the before semi-quantitatively determined substances according to Odorants Index OI = ASSA + SMUSA + SST + SFFA + SOSO SSA whereby - adjusted sum of saturated n-aldehydes (ASSA) is defined as: ASSA = SSA ∗ AF where the sum of saturated n-aldehydes in the carbon number range of C6-C10 (hexanal, heptanal, octanal, nonanal, decanal) is defined as: SSA = OA hexanal + OA heptanal + OA octanal + OA nonanal + OA decanal and the aldehyde factor is defined as: AF = 1 + SSA ∗ e SSA ∗ 15 - SMUSA stands for sum of mono-unsaturated n-aldehydes (SMUSA): -2-heptenal and -2-nonenal: SMUSA = OA Z − 2 − heptenal + OA Z − 2 − nonenal - SST stands for sum of selected terpenes: D-limonene and eucalyptol: SST = OA D − limonene + OA eucalyptol - SFFA stands for sum of free fatty acids (SFFA) with carbon numbers of C2, C4, C6, C8, C10 (acetic acid, butanoic acid, hexanoic acid, octanoic acid, decanoic acid): SFFA = OA acetic acid + OA butanoic acid + OA hexanoic acid + OA octanoic acid + OA decanoic acid and - SOSO stands for sum of styrene and acetophenone: SOSO = OA styrene + OA acetophenone and - SSA stands for the total amount of saturated aldehydes in the range of C6-C10 (Sum of saturated aldehydes, SSA) but without a factor: SSA = OA hexanal + OA heptanal + OA octanal + OA nonanal + OA decanal - adjusted sum of saturated n-aldehydes (ASSA) is defined as: ASSA = SSA ∗ AF where the sum of saturated n-aldehydes in the carbon number range of C6-C10 (hexanal, heptanal, octanal, nonanal, decanal) is defined as: SSA = OA hexanal + OA heptanal + OA octanal + OA nonanal + OA decanal and the aldehyde factor is defined as: AF = 1 + SSA ∗ e SSA ∗ 15 - SMUSA stands for sum of mono-unsaturated n-aldehydes (SMUSA): -2-heptenal and -2-nonenal: SMUSA = OA Z − 2 − heptenal + OA Z − 2 − nonenal - SST stands for sum of selected terpenes: D-limonene and eucalyptol: SST = OA D − limonene + OA eucalyptol - SFFA stands for sum of free fatty acids (SFFA) with carbon numbers of C2, C4, C6, C8, C10 (acetic acid, butanoic acid, hexanoic acid, octanoic acid, decanoic acid): SFFA = OA acetic acid + OA butanoic acid + OA hexanoic acid + OA octanoic acid + OA decanoic acid and - SOSO stands for sum of styrene and acetophenone: SOSO = OA styrene + OA acetophenone and - SSA stands for the total amount of saturated aldehydes in the range of C6-C10 (Sum of saturated aldehydes, SSA) but without a factor: SSA = OA hexanal + OA heptanal + OA octanal + OA nonanal + OA decanal (e) setting aside any polymer composition having an odorants index above 1.50.