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THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 1 -
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN
LEATHER
Tomaselli M.*, Naviglio B.*, Naviglio D.**, Comite G.*, Calvanese G.*
* Experimental station for the Leather and Tanning products Industry- Naples-Italy
** Department of Nutritional Science – University of Naples “Federico II” - Italy
Introduction
The aim of this work is to characterise the volatile substances present in leather while also
investigating the provenance of such compounds, that is the processing phase during which they
may be fixed to the leather.
The emerging environmental restrictions, which also regard the finished product (leather) deriving
from so-called eco-friendly consumption, motivate a deeper investigation of the presence of
substances released by the finished leather. This aspect is particularly important as regards the
quality of the air in an internal environment, such as the passenger compartment of a vehicle or the
room of an apartment. It is in fact known that internal furnishings made from leather must only
release a limited quantity of volatile substances but, at the same time, produce that typical “leather
smell”. The volatile substances are therefore also responsible for important organoleptic properties
of the leather product such as the smell, characterising not just the quality of the article, intentional
and pleasant smells, but in some cases imperfections connected with bad smells. In short, for leather
material the ideal is to have a perceptible but not strong smell so as not to be overly disturbing.
But what is smell? A smell may be defined as any emanation perceived through the sense of smell.
An essential condition therefore for a smell to be perceived is that it can be “smelt”; in practice this
means that the odorous substances must be in an aeriform state so as to be inhaled and come into
contact with the olfactory receptors of the nasal mucous membrane.
For the assessment and determination of the intensity of a smell, for quality control or olfactory
disturbance, the olfactometer is generally used. This consists of the sensorial analysis of an
osmogen “panel test” mixture, which is presented to a jury of selected persons (panel), and the
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 2 -
processing of the results obtained. This olfactory panel test is today regulated by a European
technical regulation, the EN 13725 for the standardisation of olfactometric analysis.
Unlike chemical analysis, olfactometric analysis does not provide the identification of a substance
or group of substances, but the units of odour of the gaseous mixture: this way the olfactory impact
can be calculated, although remaining a subjective sensation. By knowing the number of dilutions
required for the smell to be perceived by the panel, the number of units of odour per cubic metre of
the examined sample is calculated. This measurement technique permits an evaluation of the
possible synergic and masking effects too so that the concentration of smell (OU/mc) of a mixture
of compounds is not the algebraical sum of the single substances but the result of more complex
phenomena and relations. The instrument which makes it possible to carry out the right dilutions is
the olfactometer, by means of which the group of panellists judges the perceptibility of the sample.
This investigation method, while useful for the purposes of assessing the olfactory-disturbance
impact of a gaseous mixture and for commercial purposes given that it provides hedonistic
information about a product, does not however permit the identification of the various compounds
causing the smell within the gaseous mixture constituting the smell, nor their quantitative
evaluation.
This study attempts to evaluate whether it is possible to conduct a broad investigation for the
qualitative-quantitative definition of the odour of leather or of other “tannery” smells using
analytic-instrumental methods so as to define the characteristics in an objective manner but also to
identify the possible causes of olfactory disturbance in some leather articles. Against such
advantages however it is presumable that these methods will have the disadvantage of a reduced
sensitivity compared to the human “instrument” in detecting some compounds to which the sense of
smell is particularly sensitive (very low threshold for the perception of the smell), especially in the
case of mixtures of substances which together produce smells that are particularly difficult to
reproduce in the laboratory or to associate with one or a group of chemical substances.
The technical scientific approach was that of extracting the volatile substances from the leather
using the “purge and trap” technique which consists of stripping the substances from the sample at a
controlled temperature using a flow of inert gas (helium) which strips off and transports the volatile
substances to an absorbent trap where they are concentrated to then be thermally desorbed and
channelled to a gas-chromatography system connected to a mass detector for the resolution of the
volatile mixture and the identification of each single volatile component.
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 3 -
This technique enhances the result of the analysis of the volatile substances present in traces unlike
another commonly used sampling technique, the “static head space”, which only enables the
detection of the most plentiful substances and present in a concentration determined by the
equilibrium with the sample and the environment with which it is in contact.
The work done, moreover, permitted the creation of a sort of identificatory “spectrum” of the skins
represented by the gas-chromatogram showing the volatile substances eluted, a sort of leather
identity card, depending on the article (e.g. upper, clothing, furnishings) and in perspective, before
a long series of characterisations, on the tannery district of provenance.
Experimental part
11 skins at various stages of processing and for different types of article, as described below, were
investigated:
� no.4 sheepskins processed for clothing and specifically: one at the pickled state of African
provenance (called “Africa”) (sample no.1), one at the wet blue state (sample no.2), one at
the crust state (sample no.3) and one at the finished state (sample no.4)
� no.3 sheepskins processed for footwear and specifically: one at the wet blue state of
European origin (called “Europe”) (sample no.5), one at the crust stage (sample no.6) and
one at the finished state (sample no.7)
� no.1 bovine skin for footwear at the crust state (sample no.8)
� no.1 buffalo skin for furnishings at the finished state (sample no.9)
� no.1 split leather of the “by cast” article type (sample no.10)
� no.1 goatskin for footwear at the finished stage (sample no.11), with an unpleasant smell
so as to be able to compare the analytical results obtained both for skins of the same origin but at
different stages of processing, from the pickel stage to the finished product through the semi-
processed skins, and for skins at the same stage but processed so as to obtain different articles
(clothing/footwear, sheep/bovine). Such a comparison proves interesting if made relative to the
skins at different stages of the same process (samples from no.1 to no.4 and from no.5 to no.7).
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 4 -
Lastly the chromatogram relative to the finished leather with a clear defect due to the presence of
pungent, unpleasant smell (sample no. 11), was compared to all the rest to validate this analytic-
methodological approach as a technique for identifying the volatile substances responsible for smell.
About 1 gram of sample, of each type of skin mentioned above, was cut into pieces of
approximately 0.3÷04 cm2 and put into a glass container (vassel) closed hermetically inside the
“purge and trap”, system as shown in Fig. 1 in the photograph of the system used. The sample was
then heated with an infrared lamp to a temperature of 50°C, so as to speed up the removal of the
volatile substances (kinetic effect). In the “purge and trap” phase the substances are stripped using a
flow of helium at approximately 40 linear metres/min for a period of 20 minutes and then
forwarded to the absorbent trap type T10 (TENAX / Silica gel / carbon molecular sieve) kept at
room temperature (see the diagram of Fig. 2). The system then automatically activates the thermic
desorption phase (see the “desorb” diagram in Fig. 3) of the substances in the trap at a temperature
of 190 °C, to then direct them to the gas-chromatograph, fitted with a column input system, the high
temperature split/splitless, by means of a heated transfer line, thus avoiding the condensation of
some less volatile component. At the exit of the gas-chromatograph the eluted components are
directed to a quadruple type mass detector which, thanks to a dedicated software and a sufficient
library of mass spectrums of chemical substances, enables their identification and consequently the
characterisation of the mixture of volatile substances emitted by the leather.
Below are the sampling and analysis conditions adopted:
Purge and trap system make O I Analytical mod. ECLIPSE 4 F3390 :
� Purge:
transport gas = helium
flow = 40 linear metres/min
temperature = 50 °C;
time = 20 min
trap temperature = 20 °C
� Desorb:
temperature = 190 °C;
time = 2 min
Gas-chromatochromic system GC/MS make HP mod. 6890 Series and 5973 Mass Selective
detector:
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 5 -
� Injector split/splitless:
transport gas = helium
flow = 1 linear metre/min
injector temperature = 280 °C;
split ratio= 1/1
� Temperature Programme: 40 °C (5 min.) � (5 °C/min.) 200 ° C
200 ° C � (10 °C/min.) 250 °C (5 min.)
� Column:
Superchrom DB1 L=60m; ID=0,25mm; F=1µm
� Detector:
Quadrupole MS detector type HP mod.
Results and discussions
From the analysis of the gas-chromatography results, specific families of volatile organic
compounds can be identified and they or the single compounds can be associated with the leather
article produced, the animal origin of the leather and lastly the state of the leather (pickeled, wet-
blue, crust, finished).
The compounds identified were then grouped into the following families:
� Paraffinic and oleofin hydrocarbons
� Non aromatic cyclic hydrocarbons
� Mono aromatic hydrocarbons
� Polycyclic aromatic hydrocarbons
� Aldehydes
� Ketones
� Alcohols
� Esters
Table 1 shows a summary of the analytical results for each sample analysed, giving the number and
total percentage area of the compounds belonging to the families described above.
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 6 -
From the analysis of these results it may be deduced that the contribution to the emission of volatile
substances differs depending on the state of the leather. The chromatograms relative to the analysis
of the samples indicated in Figures from 4 to 14 show the identification made by the mass detector
of the volatile substances, where the figure shown in brackets alongside the name gives the
percentage of recognition.
For skins in the pickeled (see chromatogram of Fig.4) and wet-blue states (see chromatograms of
Fig.5 and Fig.8) one may deduce a preponderant presence of mono aromatic hydrocarbons such as
the alkyl-benzenes, in particular the polymethylbenzenes such as Xylene, Prenitol (Benzene,
1,2,3,4-tetramethyl-), Isodurene (Benzene, 1,2,3,5-tetramethyl-), Enimellitene (Benzene, 1,2,3-
trimethyl-) and Durene (Benzene, 1,2,4,5-tetramethyl-) and derived toluene alkyls. These
compounds may derive from the use of solvents made from oil distillates in the degreasing stages or
as stabilisers in chemical products made from surfactants and/or emulsified preservatives. This
consideration is supported by the contemporary presence, even though in relatively small quantities,
of paraffinic hydrocarbons and aromatic polycyclics such as azulene, naphthalene, indano and
tetralin (Naphthalene, 1,2,3,4-tetrahydro).
The analysis of skins at the crust state (see chromatograms of Figures 6, 9 and 11) showed a high
percentage concentration of aldehydes, ketones, esters and alcohols. As regards the aldehydic
compounds the main aldehydes identified were as follows: benzaldehyde, esanale, eptanale and
nonanale.
These aldehydes are normally contained in essential oils and/or natural resins. The presence of
aldehydes, especially those of nonanale, esanale, eptanale and benzaldehyde, is due to the use of
essential oils in the fatliquoring stage, but probably also to the so called retanning products, as
residues of synthesis (untransformed reagents). This consideration is supported moreover by the
fact that the relative integration areas of the peaks corresponding to the aldehydes decreases in
percentage terms when moving from the crust stage to the finished stage in the same process (see
chromatograms of Figures 6 with 7 and of Figures 9 with 10).
The presence of ketones is linked mainly to the use during retanning of chemical products
containing ketonic based solvents, very widely used given their low cost, high solvent effect and
anti-oxidant properties. The percentage area relative to the ketones increases considerably for the
finished leather, having a strong solvent effect on many of the polymers used in the finishing phase.
Specifically those most commonly found were isoforone (2-Cyclohexen-1-one, 3,5,5-trimethyl) and
an alkyl derivative of butirrone (4-Heptanone, 2,6-dimethyl-), and to a lesser extent alkyl
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 7 -
derivatives of eptanone, esanone and pentanone, of which the 2,2,4,4-tetrametil 3-Pentanone proved
preponderant.
The esters were found only in the skins in the crust and finished states. In fact they have a
considerable solvent effect on resins. Specifically those most utilised are butyl and exyl acetate
(Acetic acid, 2-ethylhexyl ester), as shown in the gas chromatograph analysis.
The alcohols found derive from the use of watery emulsions of organic compounds, in their role as
stabilisers of such emulsions and non-ionic surfactants, but also as solvents of the spray solutions
used in the finishing phase. Specifically, from the survey conducted 2-etil-1-esanolo and 2,6-
dimetil-4-eptanolo were found most frequently, often present as solvents, and 2,6-dimetil-2-butossi-
4-eptanolo often indicated as the stabiliser of watery emulsions or as a surfactant component.
The comparison of the chromatograms relative to skins in the same state but for different destined
uses (articles) proves interesting. From table 1 it can be seen how the gas-chromatograph analysis
of the crust relative to sample 3 (sheepskin – clothing) gave similar results to the crust in sample 6,
also of sheepskin origin but with a different destination (footwear rather than clothing), but with
very similar percentage values for the aldehyde, ketone and alkylbenzene areas in the first (% area
aldehydes=26.08 ketones=18.72 and alkylbenzenes=17.86), while in the second the percentage
composition of ketones and esters was considerably higher than the others (% area ketones=25.19
and esters=21.7 against the alkylbenzenes=8.83). The analysis of sample no.8 (crust/bovine/
footwear), however, gave totally different chromatographic results from the sheepskin crusts, with a
much higher concentration of aldehydes than of the other families of compounds (no.8 total % area
aldehydes of 63.33), almost totally characterising, to the exclusion of the alkylbenzenes (% area of
14.68), the emission of SOV from the leather.
As regards the finished leather for furnishings (sample no.9), unlike the others, a greater percentage
area was observed for the alcohols and ketones (no.5 alcohols total area %=34.26 and no. 4 ketones
of total area %=15.88) and specifically, respectively 2-butossi- ethanol and the ketones 2-butanone
and cicloesanone.
The split leather sample with “by cast finish” (sample no. 10), rather, showed a preponderant
presence of alkyl benzenes (19 substances area % equal to 27.51) compared to the other families of
compounds (area % no.3 aldehydes=0.92 no.3 ketones=1.64 no.4 alcohols=2.04 and no.3
esters=4.54).
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 8 -
Lastly, from the analysis of the leather with the unpleasant smell (sample no. 11) the presence was
observed of organic substances not found in the other leathers analysed, such as D-limonene, also
known as p-menta-1,8-diene or dipentene or citrene, a substance with a characteristic odours,
perceivable in low concentrations and unsaturated hydrocarbons such as 3-ottene. In this regard it
should be noted that during the finishing phase of this leather a caseinic binding agent was used
containing dipentene.
Conclusions
In this study it has been seen how the Purge and Trap investigation technique used with gas
chromatography and the mass detector is useful in identifying the volatile organic substances
emitted by leather and skins.
It proved possible in fact to characterise the gaseous emission of various leather articles as well as
samples of skins not yet tanned, investigating the possible presence of substances important for the
quality of the product (organoleptic properties) and the quality of the air of the confined space in
which such products are used.
This identification, as we have seen, if performed for the same skins at various stages of processing
enables the identification of the processing stage during which specific volatile substances are fixed
to the leather and which, if not eliminated thoroughly during the subsequent processing phases, will
be found on the finished article.
Lastly we have seen how this technique may prove useful in identifying the cause of some leather
defects such as the emission of bad smells or, in other cases, in identifying the volatile substances
responsible for so-called fogging.
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 9 -
Fig. 1: Photograph of the P&T system used connected to the GC/MS
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 10 -
Fig. 2: flow diagram of the “purge” phase
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 11 -
Fig. 3: flow diagram of the “desorb” phase
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 12 -
Table 1: no. of compounds and total gas-chromatogram percentage areas grouped by family of organic substances
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Sam
p 1
AFRICA SHEEPSKIN CLOTHING PICKELED
1 0.04 1 0.21 23 75.26 4 7.63 2 0.64 - - - - - -
Sam
p 2 AFRICA SHEEPSKIN
CLOTHING 1 0.78 - - 21 72.51 4 9.79 - - 1 0.4 2 0.25 - -
Sam
p 3 AFRICA SHEEPSKIN
CLOTHING CRUST 5 2 - � 12 17.86 1 0.59 6 26.08 5 18.72 3 8.45 4 10.82
Sam
p 4
AFRICA SHEEPSKIN CLOTHING FINISHED
6 4.57 - - 14 29.19 1 1.05 6 12.87 6 22.49 1 2.70 3 18.48
Sam
p 5
SHEEPSKIN EUROPEAN FOOTWEAR WET-BLUE
9 19.97 3 1.83 18 32.1 4 7.75 - - 2 0.68 1 0.27 - -
Sam
p 6
SHEEPSKIN EUROPEAN
FOOTWEAR CRUST3 3.58 4 2.01 9 8.83 1 0.46 4 11.44 6 25.19 4 16.96 4 21.7
Sam
p7
SHEEPSKIN EUROPEAN FOOTWEAR FINISHED
5 5.79 2 16.17 12 9.67 1 0.37 4 6.79 5 25.87 3 17.76 1 1.9
Sam
p 8 BOVINE ITALY
FOOTWEAR CRUST 3 1.83 1 2.47 12 14.68 1 1.17 8 63.33 1 0.16 1 1.19 2 3.69
Sam
p 9
BUFFALO ITALY FURNISHING
FINISHED5 3.88 1 3.0 5 1.93 1 0.1 6 4.49 4 15.88 5 34.26 1 3.52
Sam
pl0
SPLIT LEATHER BY CAST ARTICLE
1 0.27 - - 19 27.51 7 4.82 3 0.92 3 1.64 4 2.04 3 4.54
Sam
pl1
GOATSKIN FINISHED
FOOTWEAR "BAD SMELLING "
12 9.37 3 2.28 10 21.42 1 1.62 8 36.7 3 3.67 1 0.89 2 5.79
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 13 -
.1. Fig.4: gas-chromatogram sample no.1
15 20 25 300,0
5,0x10 6
1,0x10 7
1,5x10 7
2,0x10 7
2,5x10 7
3,0x10 7
12
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
2728
29 30
31
1 Hexanal (72%)2 p-Xylene (91%)3 Heptanal (93%)4 Benzene, 1,3-dimethyl- (97%)5 Benzene, (1-methylethyl)- (80%)6 Benzene, propyl- (91%)7 Benzene, 1-ethyl-3-methyl- (94%)8 Benzene, 1,3,5-trimethyl- (94%)9 Benzene, 1-ethyl-3-methyl- (91%)10 Furan, 2-pentyl- (80%)11 Benzene, 1,2,3-trimethyl- (94%)12 Decane (90%)13 1,2,4-Trimethylbenzene (91%)14 Indane (76%)15 Benzene, 1-methyl-3-propyl- (90%)16 Benzene, 1,2,4,5-tetramethyl- (91%)17 Benzene, 1,2-diethyl- (94%)18 Benzene, (1-methylpropyl)- (94%)19 Benzene, 4-ethyl-1,2-dimethyl- (91%)20 Benzene, 1,2,4,5-tetramethyl- (93%)21 Benzene, 2-ethyl-1,3-dimethyl- (95%)22 Benzene, 1-methyl-4-(2-methylpropy (53%)23 Benzene, 1-ethyl-2,3-dimethyl- (97%)24 Benzene, 1,2,4,5-tetramethyl- (94%)25 Benzene, 1,2,4,5-tetramethyl- (97%)26 Benzene, 1,3-diethyl-5-methyl- (91%)27 1H-Indene, 2,3-dihydro-4-methyl- (91%)28 Benzene, 1,2,3,4-tetramethyl- (97%)29 Naphthalene, 1,2,3,4-tetrahydro- (90%)30 Benzene, 1,4-dimethyl-2-(2-methylp (52%)31 Azulene (91%)
Sample no.1SHEEPSKIN AFRICAAFRICAPICKELED - CLOTHING
Abundancecounts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 14 -
Fig.5: gas-chromatogram sample no.2
15 20 25 300,0
2,0x10 6
4,0x10 6
6,0x10 6
8,0x10 6
1,0x10 7
1,2x10 7
1,4x10 7
1,6x10 7
1,8x10 7
1 2
34 5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
2122
23
24
25 26
27
2829 3031
Sample no.2SHEEPSKIN AFRICA
WET BLUE - CLOTHING
1 Cyclohexanone (91%)2 1,2-Ethanediamine, N-(phenylmethyl (45%)3 Benzene, 1-ethyl-4-methyl- (91%)4 Benzene, 1,3,5-trimethyl- (91%)5 Benzene, 1-ethyl-4-methyl- (91%)6 Piperidine (81%)7 Benzene, 1,3,5-trimethyl- (94%)8 Benzene, 1,2,3-trimethyl- (96%)9 Indane (87%)10 Benzene, 1-methyl-3-propyl- (93%)11 Benzene, 1,2,4,5-tetramethyl- (93%)12 Benzene, 1,2-diethyl- (94%)13 Benzene, (1-methylpropyl)- (93%)14 Benzene, 1-ethyl-2,4-dimethyl- (95%)15 Benzene, 1-ethyl-2,3-dimethyl- (91%)16 Benzene, 2-ethyl-1,3-dimethyl- (95%)17 Benzene, 1-methyl-4-(2-methylpropy (72%)18 Benzene, 4-ethyl-1,2-dimethyl- (96%)19 Benzene, 1,2,4,5-tetramethyl- (96%)20 Benzene, 1,2,4,5-tetramethyl- (96%)21 Nonane, 3,7-dimethyl- (53%)22 Hydroxylamine, O-decyl- (64%)23 1H-Indene, 2,3-dihydro-4-methyl- (91%)24 Benzene, 1,2,3,4-tetramethyl- (97%)25 Naphthalene, 1,2,3,4-tetrahydro- (46%)26 Benzene, 2-ethyl-1,3-dimethyl- (64%)27 Naphthalene (95%)28 Benzene, pentamethyl- (91%)29 Benzene, pentamethyl- (91%)30 1-Octanol, dimethyl- (35%)31 2-Nonen-1-ol, (E)- (50%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 15 -
Fig.6: gas-chromatogram sample no.3
15 20 25 30
0,0
2,0x10 6
1
2
3 4
5
6
7
8
9
1011
12
13
14
15
16
17
18
19
20
21 22
23
242526
27
28
29
30
31
3233
34
35 36
37
38
20 Cyclohexanone, 3,3,5-trimethyl- (80%)21 Benzene, cyclopropyl- (64%)22 Benzene, 1-methyl-3-propyl- (90%)23 Benzene, 1-ethyl-2,3-dimethyl- (87%)24 2-Butoxyethyl acetate (72%)25 Benzene, 1-methyl-4-propyl- (50%)26 Benzene, 2-ethyl-1,4-dimethyl- (90%)27 Nonanal (87%)28 Tetradecane (95%)29 2-Cyclohexen-1-one, 3,5,5-trimethy (94%)30 Benzene, 1,2,4,5-tetramethyl- (91%)31 Acetic acid, 2-ethylhexyl ester (90%)32 2-Nonenal, (E)- (89%)33 Bicyclo[2,2,1]heptan-2-one, 1,7,7- (96%)34 3,4-Dihydroxymandelic acid, ethyl (59%)35 Ethanol, 2-methoxy- (16%)36 Dodecane, 2-methyl-6-propyl- (46%)37 Azulene (81%)38 Dodecane (94%)
Sample no.3SHEEPSKIN AFRICA
CRUST- CLOTHING
1 Toluene (90%)2 Hexanal (87%)3 Acetic acid, butyl ester (64%)4 Tetrachloroethylene (95%)5 Ethylbenzene (87%)6 Benzene, 1,3-dimethyl- (97%)7 Heptanal (91%)8 Ethanol, 2-butoxy- (64%)9 Nonane (52%)10 Benzaldehyde (91%)11 Benzene, propyl- (64%)12 3-Pentanone, 2,2,4,4-tetramethyl- (89%)13 Benzene, 1-ethyl-4-methyl- (80%)14 2-Heptanone, 4,6-dimethyl- (78%)15 Octanal (55%)16 Cyclotetrasiloxane, octamethyl- (53%)17 Decane (93%)18 1-Hexanol, 2-ethyl- (83%)19 Benzene, 1-ethyl-3-methyl- (91%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 16 -
Fig.7: gas-chromatogram sample no.4
15 20 25 300
1x10 6
2x10 6
3x10 6
4x10 6
5x10 6
12
34
5
6 78 9
10
11
12
13
14
15
16 17
18
1920
21
2223
24
25
26
27
2829
30
31
32
33 34
35
36
37 38
20 Benzene, 1-methyl-3-propyl- (90%)21 Benzene, 2-ethyl-1,4-dimethyl- (90%)22 2-Butoxyethyl acetate (50%)23 Benzene, (1-methylpropyl)- (53%)24 Benzene, 1-ethyl-2,3-dimethyl- (91%)25 Nonanal (80%)26 Tetradecane (86%)27 2-Cyclohexen-1-one, 3,5,5-trimethy (91%)28 Benzene, 1,2,4,5-tetramethyl- (91%)29 Benzene, 1-methyl-4-(1-methylethyl (91%)30 Acetic acid, 2-ethylhexyl ester (90%)31 Bicyclo[2,2,1]heptan-2-one, 1,7,7- (97%)32 Phenethylamine, N-methyl-,beta,,3, (50%)33 Tetracontane, 3,5,24-trimethyl- (43%)34 Decane, 3,8-dimethyl- (46%)35 1H-Indene, 1-methylene- (81%)36 Dodecane (95%)37 Undecane, 2,6-dimethyl- (96%)38 4-Octanone (52%)
Sample no.4SHEEPSKIN-AFRICA
FINISHED - CLOTHING1 Toluene (90%)2 Hexanal (72%)3 Acetic acid, butyl ester (64%)4 Tetrachloroethylene (94%)5 Benzene, 1,3-dimethyl- (94%)6 Heptanal (90%)7 Benzene, 1,3-dimethyl- (90%)8 Benzene, (1-methylethyl)- (50%)9 Benzaldehyde (93%)10 Benzeneacetaldehyde (50%)11 3-Pentanone, 2,2,4,4-tetramethyl- (90%)12 2-Heptanone, 4,6-dimethyl- (86%)13 Octanal (95%)14 1,2,4-Trimethylbenzene (90%)15 Decane (90%)16 1-Hexanol, 2-ethyl- (90%)17 Benzene, 1,2,3-trimethyl- (94%)18 Cyclohexanone, 3,3,5-trimethyl- (90%)19 Benzene, 1,1'-(1-ethenyl-1,3-propa (78%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 17 -
Fig.8: gas-chromatogram sample no.5
15 20 25 300,0
2,0x10 6
4,0x10 6
6,0x10 6
1 2 34 5 6
7
8
9
10
11
1213
14
15
16
17
18
19
2021
22
23
24
25
26
2728
29
30
31
32
33
34
35
36
37
38
39
40
41
Sample no.5SHEEPSKIN EUROPEAN
WET BLUE - FOOTWEAR1 Ethanol, 2-butoxy- (59%)2 Nonane (90%)3 1,3-Cyclohexanedione, 5,5-dimethyl (46%)4 4-Heptanone, 2,6-dimethyl- (60%)5 Benzene, 1,3,5-trimethyl- (50%)6 Benzene, 1-ethyl-3-methyl- (64%)7 Cyclohexene, 1-ethyl- (35%)8 Benzene, 1,3,5-trimethyl- (90%)9 Decane (96%)10 Benzene, (1-methylpropyl)- (59%)11 Benzene, 1,3,5-trimethyl- (58%)12 Dodecane, 2,6,11-trimethyl- (46%)13 Tetradecane (46%)14 Cyclodecane (94%)15 Benzene, 1-methyl-3-propyl- (83%)16 Benzene, 1-ethyl-3,5-dimethyl- (87%)17 Benzene, 1,2-diethyl- (45%)18 Benzene, 1-methyl-3-propyl- (68%)19 Benzene, 2-ethyl-1,4-dimethyl- (91%)20 Benzene, methyl(1-methylethyl)- (91%)21 Benzene, 2-ethyl-1,3-dimethyl- (90%)22 Indan, 1-methyl- (72%)23 Cyclopentane, 1-ethyl-2-methyl-, c (55%)24 Undecane (94%)25 Benzene, 1-ethyl-2,4-dimethyl- (90%)26 Benzene, 1-methyl-4-(1-methylethyl (91%)27 Dodecane, 2,6,10-trimethyl- (53%)28 Benzene, 1-methyl-2-(1-methylethyl (64%)29 Benzene, (2-methyl-1-butenyl)- (38%)30 Benzene, 2-ethyl-1,4-dimethyl- (50%)31 Benzene, 1,2,3,4-tetramethyl- (90%)32 Benzene, 1-ethyl-2,3-dimethyl- (47%)33 Benzene, (1,1-dimethylpropyl)- (59%)34 Decane, 1,1'-oxybis- (90%)35 Naphthalene (94%)36 1H-Indene, 2,3-dihydro-1,2-dimethy (76%)37 Dodecane (96%)38 Benzene, 1,3-dimethyl-5-(1-methyle (76%)39 Undecane, 2,6-dimethyl- (96%)40 Benzene, pentamethyl- (81%)41 1H-Indene, 2,3-dihydro-1,3-dimethy (70%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 18 -
Fig.9: gas-chromatogram sample no.6
15 20 25 300,0
2,0x10 6
4,0x10 6
6,0x10 6
12
3
4 5
67
8
9
10
11
12
13
14
15
16
17
18 1920 212223
24
25
26
27
28
2930
31
32
33
34
35
Sample no.6SHEEPSKIN EUROPEAN
CRUST - FOOTWEAR1 2-Propanol, 1-methoxy- (90%)2 Toluene (90%)3 Hexanal (89%)4 Acetic acid, butyl ester (72%)5 Ethylbenzene (58%)6 Benzene, 1,3-dimethyl- (94%)7 Heptanal (94%)8 Ethanol, 2-butoxy- (64%)9 Benzaldehyde (94%)10 Benzene, propyl- (64%)11 3-Pentanone, 2,2,4,4-tetramethyl- (94%)12 Benzene, 1,3,5-trimethyl- (64%)13 2-Heptanone, 4,6-dimethyl- (90%)14 4-Heptanol, 2,6-dimethyl- (86%)15 Benzene, 1,2,4-trimethyl- (87%)16 Decane (91%)17 1-Hexanol, 2-ethyl- (90%)18 Benzene, 1-ethyl-2-methyl- (90%)19 Cyclohexanone, 3,3,5-trimethyl- (94%)20 Cyclohexene, 1-methyl-4-(1-methyle (96%)21 Cyclohexane, 1-methyl-2-propyl- (64%)22 Cyclobutanone, 3,3-dimethyl- (64%)23 Benzene, 1-ethyl-3,5-dimethyl- (80%)24 2-Butoxyethyl acetate (72%)25 Benzene, 1-ethyl-3,5-dimethyl- (72%)26 Nonanal (64%)27 Undecane (93%)28 2-Cyclohexen-1-one, 3,5,5-trimethy (91%)29 Cyclopentane, ethyl- (43%)30 Cyclohexane, 1,2-dimethyl-, trans- (72%)31 Acetic acid, 2-ethylhexyl ester (90%)32 Camphor (97%)33 3,4-Dihydroxymandelic acid, ethyl (59%)34 Naphthalene (64%)35 Dodecane (95%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 19 -
Fig.10: gas-chromatogram sample no.7
15 20 25 300,0
2,0x106
4,0x106
6,0x106
8,0x106
1 2 3 4
5
6
7
8
9
10
11
12
13
14
15
16
17181920
212223
24 25
26
27
28
29
30
3132
33 34
35
Sample no.7SHEEPSKIN EUROPEAN
FINISHED - FOOTWEAR1 Toluene (90%)2 Hexanal (53%)3 Acetic acid, butyl ester (78%)4 Ethylbenzene (91%)5 Benzene, 1,3-dimethyl- (91%)6 Heptanal (94%)7 Ethanol, 2-butoxy- (78%)8 Benzaldehyde (94%)9 Benzene, propyl- (46%)10 4-Heptanone, 2,6-dimethyl- (93%)11 Benzene, 1,3,5-trimethyl- (86%)12 2-Heptanone, 4,6-dimethyl- (90%)13 4-Heptanol, 2,6-dimethyl- (74%)14 Cyclotetrasiloxane, octamethyl- (56%)15 Decane (95%)16 1-Hexanol, 2-ethyl- (78%)17 Benzene, 1-ethyl-3-methyl- (86%)18 Cyclohexanone, 3,3,5-trimethyl- (95%)19 Benzene, 2-propenyl- (64%)20 Cycloheptane (60%)21 1-Hexene, 5-methyl- (62%)22 Benzene, 1-ethyl-2,3-dimethyl- (80%)23 Pentane, 2,4-dimethyl- (50%)24 Benzene, 1-methyl-2-propyl- (50%)25 Benzene, 2-ethyl-1,4-dimethyl- (90%)26 Nonanal (72%)27 Undecane (95%)28 2-Cyclohexen-1-one, 3,5,5-trimethy (94%)29 Benzene, 1,2,3,5-tetramethyl- (58%)30 Cyclopentane, 1,2,3-trimethyl-, (1 (70%)31 Camphor (97%)32 Cyclopentasiloxane, decamethyl- (90%)33 Benzene, 1-methyl-4-(2-methylpropy (59%)34 Azulene (81%)35 Dodecane (97%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 20 -
Fig.11: gas-chromatogram sample no.8
10 15 20 25 30 35
0
500000
1000000
1500000
2000000
1 2
3
4 5
6
7
8 910
11
1213
14
15
161718
1920
21 22
23
24
25 26
27
28
29
3031
Sample no.8BOVINE
CRUST - FOOTWEAR
16 Decane (83%)17 1-Hexanol, 2-ethyl- (59%)18 Benzene, 1,3,5-trimethyl- (87%)19 2-Octenal, (E)- (87%)20 Benzene, 1-ethyl-2,3-dimethyl- (86%)21 2-Butoxyethyl acetate (64%)22 Benzene, 1-ethyl-3,5-dimethyl- (86%)23 Nonanal (91%)24 Heptane, 2,4-dimethyl- (72%)25 2-Cyclohexen-1-one, 3,5,5-trimethy (74%)26 Benzene, 1,2,3,4-tetramethyl- (80%)27 Cyclopentane, 1,2,3-trimethyl-, (1 (72%)28 2-Nonenal, (E)- (97%)29 Silane, [[4-[1,2-bis[ (trimethylsil (43%) )))))30 Azulene (76%)31 Dodecane (74%)
1 Pentanal (64%)2 Toluene (86%)3 Hexanal (93%)4 Acetic acid, butyl ester (78%)5 Ethylbenzene (56%)6 Benzene, 1,3-dimethyl- (95%)7 Heptanal (94%)8 p-Xylene (87%)9 Benzaldehyde (91%)10 Benzene, propyl- (64%)11 Benzene, 1-ethyl-2-methyl- (91%)12 Benzene, 1-ethyl-4-methyl- (86%)13 Benzene, 1,2,3-trimethyl- (80%)14 Octanal (87%)15 Benzene, 1,2,3-trimethyl- (83%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 21 -
Fig.12: gas-chromatogram sample no.9
5 10 15 20 25 30 35 400,0
2,0x10 6
4,0x10 6
6,0x10 6
8,0x10 6
1,0x10 7
1
23 4
5
6
7
8910
11
12
13
14
15
1617
18
19
20
21 22 23
24
25
26
27
28
29 3031 32
Sample no.9BUFFALO
FINISHED - FURNISHINGS
1 Carbon dioxide (4%)2 Acetone (59%)3 Isopropyl Alcohol (78%)4 Methylene Chloride (93%)5 Silanol, trimethyl- (64%)6 Hexane (91%)7 1-Propanol, 2-methyl- (87%)8 1-Butanol (87%)9 1-Penten-3-ol (47%)10 Pentanal (43%)11 Toluene (91%)12 2-Heptene (55%)13 Acetic acid, butyl ester (90%)14 2-Hexenal, (E)- (93%)15 2-Butanone (35%)16 Ethylbenzene (91%)17 Benzene, 1,3-dimethyl- (91%)18 Cyclohexanone (95%)19 Heptanal (93%)20 Ethanol, 2-butoxy- (95%)21 Benzaldehyde (94%)22 Benzene, 1-ethyl-2-methyl- (91%)23 Benzene, 1-ethyl-2-methyl- (83%)24 2-Pentanone, 3-methyl- (9%)25 1-Hexanol, 2-ethyl- (90%)26 Heptane, 3-methyl- (43%)27 Nonanal (94%)28 Cyclopentane, 1,2,3-trimethyl-, (1 (72%)29 Cyclopentasiloxane, decamethyl- (74%)30 Naphthalene (74%)31 Tridecane (96%)32 Tetradecane (97%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 22 -
Fig.13: gas-chromatogram sample no.10
10 15 20 25 30 35 40
0,0
2,0x10 5
4,0x10 5
6,0x10 5
8,0x10 5
1,0x10 6
12
3
4
5
6
7
8
9
1011
12
13
14
15
161718
19
20
21
22
23
24
25
26
27
28
29
30
31
32
3334
35
36
3738 39 40 41
42
43
44
45
46
47
Cam pione n.10CROSTA
ARTICOLO BY CAST
25 B enzene, 1-methyl-4-propyl- (90% )26 B enzene, 4-ethyl-1,2-dimethyl- (94% )27 B enzene, 1-ethyl-2,3-dimethyl- (94% )28 B enzene, 2-ethyl-1,3-dimethyl- (91% )29 B enzene, 1-ethyl-2,4-dimethyl- (95% )30 A cetic acid, 2-ethylhexyl ester (90% )31 1H -Indene, 2 ,3-dihydro-4-methyl- (91% )32 1H -Indene, 2 ,3-dihydro-5-methyl- (60% )33 B enzene, 1-methyl-2-(1-methylethyl (59% )34 B enzene, (1,1-dimethylpropyl)- (78% )35 A zulene (94% )36 D odecane (81% )37 B enzene, 1-ethyl-4-(1-methylethyl) (64% )38 1,2-B enzisothiazole-3-carboxylic a (78% )39 1H -Indene, 2 ,3-dihydro-4 ,7-dimethy (90% )40 1H -Indene, 2 ,3-dihydro-1 ,2-dimethy (87% )41 1H -Indene, 2 ,3-dihydro-1 ,6-dimethy (72% )42 Tridecane (93% )43 N aphthalene, 2-methyl- (91% )44 A cetic acid, [bis[(trimethylsilyl) (50% )45 B iphenyl (74% )46 Tetradecane (96% )47 N aphthalene, 1-ethyl- (45% )
1 H exane (90% )2 1-P ropanol, 2-methyl- (91% )3 1-B utanol (78% )4 Toluene (90% )5 H exanal (59% )6 A cetic acid, butyl ester (74% )7 2-B utanone (7% )8 E thylbenzene (91% )9 B enzene, 1,3-dimethyl- (90% )10 C yclohexanone (94% )11 H eptanal (72% )12 p-Xylene (91% )13 B enzaldehyde (94% )14 B enzene, propyl- (64% )15 B enzene, 1-ethyl-2-methyl- (91% )16 B enzene, 1,2 ,4-trimethyl- (87% )17 B enzene, 1-ethyl-4-methyl- (86% )18 Octanal (83% )19 B enzene, 1,3 ,5-trimethyl- (94% )20 1-H exanol, 2-ethyl- (80% )21 B enzene, 1-ethyl-3-methyl- (91% )22 B enzene, 2-propenyl- (72% )23 B enzene, 1-methyl-2-propyl- (91% )24 B enzene, 1-ethyl-3,5-dimethyl- (90% )
Abb
onda
nza,
cou
nts
T em po, m in
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 23 -
Fig.14: gas-chromatogram sample no.11
15 20 25 30
0,0
2,0x105
4,0x105
6,0x105
8,0x105
1,0x106
1,2x106
1
2
3
45
6
7 8
9 1011
12
13
1415
16
17
1819
20
21
22
2324252627 28
29
30
31 323334
3536 37
383940
41
42
4344
23 Eicosanoic acid, 2-ethyl-2-methyl- (37%)24 Benzeneacetaldehyde, ,alpha,-methy (43%)25 Benzene, 1,2,3,5-tetramethyl- (80%)26 Heptane, 3-methyl- (50%)27 Heptadecane, 7-methyl- (38%)28 Benzene, 1-ethyl-2,3-dimethyl- (38%)29 Nonanal (90%)30 Dodecane (86%)31 2-Cyclohexen-1-one, 3,5,5-trimethy (59%)32 5H-5-Methyl-6,7-dihydrocyclopentap (53%)33 Benzene, 1,3-diethyl- (80%)34 Hexyl octyl ether (43%)35 Cyclopentane, 1,2,4-trimethyl-, (1 (58%)36 2-Nonenal, (E)- (58%)37 Cyclopentasiloxane, decamethyl- (42%)38 1-Hexene, 4,5-dimethyl- (47%)39 Dotriacontane (53%)40 Decane, 3-methyl- (53%)41 Decanal (64%)42 Dodecane (90%)43 Undecane, 2,6-dimethyl- (58%)44 2-Methoxyphenyl isothiocyanate (27%)
Sample no.11GOATSKIN
FOOTWEAR - FINISHED1 2-Oxetanone, 4,4-dimethyl- (50%)2 Toluene (91%)3 Hexanal (86%)4 Acetic acid, butyl ester (39%)5 Ethylbenzene (59%)6 Benzene, 1,3-dimethyl- (94%)7 Heptanal (81%)8 p-Xylene (81%)9 1-Decanol, 2-ethyl- (50%)10 Benzaldehyde (78%)11 1,3,5-Cycloheptatriene, 7-ethyl- (38%)12 Benzene, 1-ethyl-2-methyl- (91%)13 5-Hepten-2-one, 6-methyl- (46%)14 Cyclopentanol, 3-methyl- (50%)15 Benzene, 1-ethyl-2-methyl- (59%)16 Octanal (46%)17 Benzene, 1,2,3-trimethyl- (83%)18 Octane, 4-ethyl- (83%)19 3-Octene, (E)- (43%)20 Benzene, 1,2,3-trimethyl- (46%)21 Decane, 4-methyl- (72%)22 D-Limonene (95%)
Abundance,counts
Time, min
THE CHARACTERISATION OF VOLATILE ORGANIC COMPOUNDS IN LEATHER - 24 -
Bibliography
1 Rapporti gruppo Scientifico Italiano Studi e Ricerche (GSISR), Milano, 2004
2 B. Naviglio, M. Tomaselli, D. Naviglio, C. Raia, Caratterizzazione gas-cromatografica
delle componenti volatili di pelli e cuoi, CPMC Anno 78 – n.2 marzo/aprile 2002
3 Dr. S. Adams, Dr B. Wegner and Dr. P. Weyland, Fogging from finishes in car leather,
Leather January 2000
4 Dr. Amanda Long, Automotive Leather – Constituents of Fogging Materials Revelealed,
Meeting the Environmental Challenge, November 2001, Kenilworth UK
5 EPA Method 5035, Closed-System Purge-and-Trap and Extraction for Volatile Organics in
Soil and Waste Samples, rev. 0 December 1996.
6 EPA Method 8260B, Volatile Organic Compounds by Gas Chromatography/Mass
Spectrometry (GC/MS), rev. 2 December 1996
7 EPA Method 8270C, Semivolatile Organic Compounds by Gas Chromatography/Mass
Spectrometry (GC/MS), rev. 3 December 1996
(N.d.t.: non è stato possible sovrascrivere nella figura n.13. Vogliate apporre la seguente traduzione: CAMPIONE N.10 � SAMPLE No 10 CROSTA � SPLIT LEATHER ARTICOLO BY CAST � BY CAST ARTICLE ABBONDANZA, COUNTS � ABUNDANCE, COUNTS