Researches on the isomers of monounsaturated fatty By · PDF fileResearches on the isomers of...
Transcript of Researches on the isomers of monounsaturated fatty By · PDF fileResearches on the isomers of...
j.
FISHERIES RESEARCH BOARD OF CANADA
Translation Series No. 1348
Researches on the isomers of monounsaturated fatty acids of vegetable oils by chromatography-mass
spectrometry.
By C.M. Zorzut and P. Capella
Original title: Ricerche sugli isomeri degli acidi grassi monoinsaturi di oli vegetali mediante gascromatografia - spettrometria di massa.
From: La rivista italiana delle sostanze Grasse, XLVI (Feb.): 66-72, 1969.
Translated by the Translation Bureau(KQA) Foreign Languages Division
Department of the Secretary of State of Canada
Fisheries Research Board of Canada Halifax Laboratory
Halifax, N.S.
1969
21 Pages typescript
.1 73 1 7' '1
INTO - EN TRANSLATED FROM - TRADUCTION DE
Italian Znglish
PAGE NUMBERS IN ORIGINAL NUMÉROS DES PAGES DANS
L'ORIGINAL DATE OF PUBLICATION DATE DE PUBLICATION
PUBL ISH ER - ÉDITEUR
Stazione Sperimentalè per l'in-dustrie degli olite dei grassi
6( - 72 VOLUME PLACE OF PUBLICATION LIEU DE PUBLICATION
ISSUE NO. NUMÉRO
YEAR ANNÉE
NUMBER OF TYPED PAGES NOMBRE DE PAGES
DACTYLOGRAPHIÉES
1969 XLVI Feb. Milan 21.
REQUEF- ING DEPARTMEN1 Fisheries & Forestry MIN ISTERE-CLIENT
TRANSLATION BUREAU NO. NOTRE DOSSIER N° 9,8 f
BRANCH OR DIVISION DIRECTION OU DIVISION
Fisheries Research Board TRANSLATOR (INITIALS) TRADUCTEUR (INITIALES)
KQA
PERSON fiEQUESTING DEMANDE PAR Dr T.G. ânkmor, Holirgy LRb,
DATE COMPLETED ACHEVÉ LE L)(,,C)
DATE OF REQUEST DATE DE LA DEMANDE 31st. October 1969
FLD 69A
• DEPARTMENT OF THE SECRETARY OF ',I'ATE
TRANSLATION BUREAU
FOREIGN LANGUAGES
SECRÉTARIAT D'ÉTAT
BUREAU DES TRADUCTIONS
DIVISION DES LANGUES DIVISION CANADA ÉTRANGÈRES
AUTHOR - AUTEUR
C.M. Zorut and P. Capella.
TITLE IN ENGLISH - TITRE ANGLAIS
Researches on the isomers of monounsaturated fatty acids of vegetable oils by chromatography7muukFearomerv
Title in foreign language- it z -oreign- charaeters)
RicerChe sugli isomeri degli acidi rr rassi monoinsaturi di oli vezetali mediante gascromatbgrafia-spettrometria di massa
REURENCE IN FOREIGN I7 ANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHARACTERS.
REFERENCE EN LANGUE ETRANGÉRE (NOM DU LIVRE OU PUBLICATION), AU COMPLET.TRANSCRIRE EN CARACTÉRES PHONÉTIQUES,
La. Rivista Italiana delle sostanze Grasse
REFERENCE IN ENGLISH - RÉFÉRENCE EN ANGLAIS
The Italian Review of Fatty Substances
769-18-14 YOUR NUMBER VOTRE DOSSIER N°
SOS-200-10-6 (REV. 2/88)
CANADA
OEPARTMENT OF THE SECRETARY OF'STATE
TRANSLATION BUREAU •
FOREIGN LANGUAGES DIVISION
r ri
SECRéTAPIÀT
BUREAU DES TRADUCTIONS
DIVISION DES LANGUES ÉTRANGÈRES
YOUR NO. DEPARTMENT DI VISION/SR ANCH CITY
VOTRE N ° MINISTèRE Di visioN/oi rurc TION VILLE
Dept. of Fisheries Ottawa OUR NO. LANGUAGE TRANSLATOR (INITIALs) DATE
NOTRE N ° LANGUE TRADUCTEUR UNITIALES)
3837 Italian K.Q.A. 3, DEC, 69
• SOS-200....10-31
RESEARCHES ON THE ISOMERS OF 'MONOUTU-:-.(ATED FATTY
ACIDS OF VEGETABLE OILS BY CEROETC.GRAi(iY. -
MASS SPECTROMETRYW
by C.M. Zorzut and P. Capella Institute Of Agrarian Chemistry and Agrarian Industry of the
University of Bologna.
RESEARCHES ON THE ISOMERS OF MONOUNSATUHATED FATTY ACIDS C£, VEGETABLE OILS BY CHROMATOGRAPHY MASS SPECTROMETRY
The isomerssof monounsaturated fatty acids of some vegetable
oils were studied by the combination of gas chromatography-mass
spectrometry after conversion of the monounsturated fatty
acids into the corresponding trimethylsilyloxy (TMSO) der-
ivatives.
The results allowed ustoshow that - with the only exception of
parsley seed oil - the most widely represented isomers are the
9-cis-hexadecenoic, the 9-cis-octadecenoic, the 11-cis-eico-
senoic and the 13-cis-docosenoic. While in general the data
previously known in the literature have been confirmed the
presence of isomers not yet reported has been demonstrated,su as
the 6-cis-hexadecenoic,.the 8-cis and 9-cis-eicosenoic in par-
sley seed oil, and the 13-cis-octadecenoic in rapeseed and
mustard seed oil.
The results are then discussed in the light of the present
knowledge on unsaturated fatty acid biosynthesis.
• Paper read at the IX Italian Congress on Studies or Fatty Substances, Bologna, 10-12 June, 1968.
UNED;TED 177:1-sy'::SLATION
Introduction:
The stùdy Cf the structure of monounsaturated fatty acids
of oils and of natural fats has led to the conclusion that,
except for rare exceptions, these have the double bond in pos-
itions 9, 10 (acids of 16 and 18 carbon atoms) or in the pos-
ition 11, 12 and 13, 14 (acids of 20 and 22 carbon atoms
respectively).• The knowledge with regard to the presence of
their isomers of position is both inadequate and fragmentary.
An examination of the most recent.literature has led us
to the conclusion that numerous insoluble structural compo-
nents are widely diffused in the nature]. oils (1-3).
The knowledge of the composition o in structural isomers of
monounsaturated fatty acids,nreents the following interesting
aspects:
1) Biolorically with regard to the natural mechanisms of their
synthesis and their relaboration and therefore of the veg-
etable and animal phYsiology in the catabolic and anabolic
processes of the fatty substances; in this context,
studies on.filo97enesis and taxonomy are also important,
especially in regard to the vegetable organisms.
2) Industrialleoth in relation to the modifications_undenTone,by the fatty -
/acids in the course of the processes of preparation of the
edible oil products (4) and also the exploitation of sources
of the composts with a particular structure.
In the study of the monounsaturated fraction of the fatty
methods most commonly used acids, previously isolated, the
-3-
are base:, on the *oxidated breaking-up of the ,nolecule in the
positions of the double bonds and gnstromatoraphic analysis
on chromaography of the oxidized fragments (2, 5-12). The
aforesaid methods are complicated, above sll in their quan-
titative spect, with regard to the possiblity of formation
of products with«further oxidative domolition of the orimary
fragments and from the fact that acids with different lumbers
of carbon atoms but having the same position of unsaturation,
give - ;.ace to a'product in common; the method of the oxidative
domolition, moreover, often imposes difficult processes of en-
riching and purification, -%Yllen the msnounsfiturribed fatty acids
present in small percentages in the mixture must be isolated.
Other methods (13) provide for the use of the tubular open
column (capillary) for gastromatoraphic analysis of the , sters
of the monounsaturated fatty acids the determination
is in this case possible only for the ocids hs,ving the double
bonds close to the aliphatic extremity of the molecule.
New prospects for a brilliant solution of the problem have
opened up with the application of mass spectrometry in the stu-
, dy of the fatty acids.
This method of experimentation has produced definite re-
sults in the definition of the structure of saturated esters
(14-18), while It has been halted_when faced with the esters of
the monounsaturated fatty acids in cases suchœ: the molecule
undergo/ in fact, under an electronic impact, phenomena of
breaking up of the double bond which leads to a constant sta-
tistical distribution of the position of unsaturation along the
molecule. Numerous research workers have us a consequence
turned their attention to the various derivatives of the es-
ters of monounsaturated fatty acids obtaining, in some cases
a good spectral characterization of the composts witha dif-
ferent position of the double bond andW . ,, different steric
configuration ( .19-22). The examination of the spectrums of
the mass of pure composts did not however &ive any hope for the
possibility of determining 'either .the presence or the structure
of composts represented in small percentages in a mixture of
fatty acids. .
Recent . research (23) undertaken by us on the suitable
derivatives of the esters of some oure monounsatsrated fatty
acids has enabled . us to determine how far these derivatives could
be similar 1h order to determine the position of the double
bond and has suggested to us the possibility of defining the
structure of their isomers present in complex mixtures.
The procedure adopted requires the preparation of di-
trimethyl silyloxy (TMS0) derivatives of the methyl esters
of monounsaturated fatty acids, according to the following
reaction method.:
1 0sO 4 — > C = C <
2 I Na 2S01 I OH OH
HMDS I
TMCSC C I I
TMSO OTMS
clove HMDS = esametildisilasatio; l'AACQ trinirtitrinrOSilanO.
where HMS = hexamethyllic41asane TMCS trimethylchlorosylane
- 5-
These composts were subsequently an-Jlysed by mass -.)ent-
rometry. .Plie . main fragmentation too lacebecase the
breakiniz ._kp of the CC bond in the original nosftion of the
double bond, as illustrated in the followinF formula:
CH,— [CH2 ], —CH — CH —(CH2 ), COOR 1 TMSÔ ; ÔTMS
The mass spectrums show 9 in fct, two peaks of nigh
intensity corresponding to the fragments a c b of each isomer.
In figure;1, 2, and 3 there are reproduced, for exa.nrqe, the
mass spectrums of TMSO derivatives of the methyl esters of oleic
acid, palmitoleic and petroselineic
In these mass spectrums, which facilitate conSiderably
the determination of the position that the double bond occupied .
prior to oxidization of the fatty acids, the intensity of the
main fragments (a & b) is always sufficient for the pur-
poses of their identification, even in Cases where the product
analysed contains numerous isomers of position and when these
are present in small percentages. It is interesting further to
note, in order to make a quantitative examination of the spec-
trums of thé . bixturè of the monounsaturated fatty acids, that
the relative intensity of the ions a and b varies
ly with the position of the double bond, and therefore in a
only slight-
-6-
manner which we consider to be regulated by a precise law.
The mass ppectrums of the derivatives of monounsaturated
fatty acids'stereoisomers do not show. such :_jnificant differen-
ces as to define their geometrical structure.
This however does not constitute a handicap in the method,
si:ace the isomers cis-trans can be easily separated for pur-
poss of chromatography on a thin strata •4), before the
preparation of the derivatives.
The favourable aspects of fragmentation under el-
ectronic impact of the , composts examined in the aforementioned
research has induced us to study the isomers of position and
the geometrical ones,of the monounsaturated acids present in
the following oils: rapeseed, parsley, soya, olive, flax,
mustard, sunflower, maize, peanuts and hemp.
Lx_p_primental Part.
The samples of the oils analysed were extracted with hex-
ane from seed- or from the oily fruit. The fatty acids, obtain-
ed for purposes of saponification, were then esterified with
methanol- BF3 at 12%.
By means of chromatography on a thin strata of silica gel
G/AgNO3 (2L) the corresponding fractions were then separated
from the methyl esters of the cis-monounsaturated and trans-
monounsaturated acids.
spectrometry.
PM 445
s 10
combination
100
50
-7-.,
Thse fractions were then transformed into the corres-
ponding di-trimethylsilyloxy derivatives according to the method
described previously (23) and analysed directly by means of the
of gaschromatography-mass
• n
Ue$10ertstr41100:111»»
11411
cid
(C) 332
T r --t
415 I
r• 400 rn>s
it 1 it?
Figure 1 • Spettro dl massa del TMSO derlvato dell'oleato dl metlle.
Figure 1 - Mass spectrum of TM() derived from methyl oleate.
Figure 2 • Spettro di mess. del TMS0 derivate del petrosellnato dl metile.
- Mass spectrum of TMSO derived from methyl-petro selinate.
Figure
13
—r- t
-8-
It •
CH,f01 1,—r--1-.1H-KeytœrtCH,
TM: LI
100
na 4/4
1111
200 300
10
/143 451
,
1 4o0 1 ' 'fr• T'ut
11 14,1,41, 1)
• CO CO 14? 158
332
Id 11.3
(bi 2511
'figure 3 • Spettro cil mess* del TMSO derivato del palmItoleato dl motile,
Figure -3 - Mass spectrum of TM'S° derived from methyl palmytholeate.
For this purpose a_ gaschromatoi!.:raph -mass spectrometer
LKB model 9,000 was utilized (°). The Fastromatographic ap-
paratus for the introduction of the samples was furnished with
a spiral column in glass measuring 2 m X 3 mm, filled with SE
30 at 2.5% on das Chrom P, 100-120 mesh previously washed with
acids and silanated. Temperature of the column: 220 degrees
C; temperature of the evaporator: 270 degrees C; carrier gas:
He, 30 ml/min. The molecular separater was maintained at 240
degrees C and the ionizing source at 310 degrees C. Power
of ionization 70 eV; current of . ionization 20 A. The spec-
trums were registered in 5 sec (m/e 1 - 400) on an apex of
• gasoromatographic peaks. •
(*) Apparatus in use at the Centre of mass spectrometry of the University of Milan. Ne wish to offer our thanksto the directors of the Centre for their kind permission to use the above and Dr. Tito Salvatori for his courteous col-laboration.
-9-
Results an-.\ review
Figure • is a reproduction of a gascromatogram of TMS0
derived from the monounsaturated acids of rapeseed oil. The
separation c.f the derivatives with differing numbers of carbon
atoms is total and it is therefore possible to rcord the
spectrums 'f the mass of single peaks without Interference.
cI
elt
z_o
Figure 4 - Gascromatogramma del TMSO derivati degli este. ri nieIlikI degli acldi 91-Hsi monoinsaturi dell'olio dl colza. :.;
Figure 4 - Gascromatogram of TMSO derivatives of the methyl esters of monounsaturated fatty acids of rapeseed oil.
Three main peaks are present due to the homologous acids
with 18, 20 and 22 carbon atoms.
The central zones of their mass spectrums are reproduced
in Figure 5.
These confirm that the peak C18 contains, side by side
with the predominant cis-9-octadecenoic acid, small quantities
of the isomerscis-11 - and cis-6-ottadecenoic. This last
23
-10-
iti;omer was not referred to in the work of Kuennel (2) whose
isearches were . undertaken using the method of oxidative dem-
olition.
The isomer cls-11-eicosenoic 9 and small quantities of the
isomer cis-13 are present, instead, in the :)eak C 20 while in the peak
C 92 there is only the isomer cis-13-docosenoic0 In this last case
we were unab-le to confirm the presence of the isomer cis-lci-
do.?,osenoic, which was found instead by Kuemmel.
1 8
“
259
C2
cl Au ) 388
là( c(à ") 315 360
1
te(Au) 315
215
'3(L1 1 ,) 181
°go) 215
78
50
25
WO
75
60
25
100
75
eo
23
100
7
50
25
• ict)
/GI
GO
• 20
u(t)...)
21:5
otA 0
gA5) C 20
p .211 !!!JA-o
287
Figura S - Spettri di masse del TAISO deriveti degli esteri metiliel degli ncidi gressi monoinsaturi dell'ollo di colza.
150 200 250 m/e 300 350 ' 400.
Figure 5 - Mass spectrums of TMS0 derivatives of the methyl esters of monounsatured fatty acids of rapeseed oil.
(M11
259 ed) b(A0
Lau
e(à,) 332
MO
75
50
• Flgerw 6 e Spettrl di massa del TMS0 derived degll esterl me.
Mick. digit «WI grass, monoinsaturl dell'ollo di prenemolo.
b(An) 0( ) ci(Ani 217 245 257
12(A1) 259
i u(6 .) b2(5A711) i 285i
+2
c(t) i c3( ‘;‘; ) 3c (6% 1 )
318
2à0 300 350 46-0 eth
u(14) „ 215 d‘tito
! 243
C o 2
150 200
Figure 6 - Mass spectrums of TMSO derivatives of methyl esters of monounsaturated fatty acids of parsley oil.
-12-
We must mention however l evenif our reservations are valid with
regard to the possibility of errorsresulting_from the method of
analysis by means of oxidative demolition in the case of small
quantities of isomers, that our research was done . on one
sample only and has, therefore, no statistical validity.
The composition of the monounsaturated fatty acids of par-
sley oil is of considerable interest. The mass spectrums of
TMS0 derivatives of the acids C1 6, Cg, C20 are reproduced
in Figure 6.
It.may be pointed out that the hexadecenoic acids are com-
posed of quantities which have more or less equal isomers cis-
6-hexadecenoic and cis-9-hexadecenoic. The presence of the cis-
6-hexadecenoic acid, though this is not surprising, was J,s fa) as
we know never traced before in oils and vegetable fats, but
only in the fat of hair (25) and in the fat of human excretion
(26). The spectrum of the acids with 18 carbon atoms, confirms,
instead, what has been stated previously (27, 28): às in all
the oils of umbelliferous seeds, thé petroselinic (cis-6-octa-
decenoic) forms the major part, together with a lesser quantity
of oleic acid (cis-9-octadecenoic). The composition of the peak
C20 = 9
present: the cis-6, the cis-8, the cis-9, and the cis-11 eico-
senoic, as can be Pointed out from the couples of peaks at m/e
285-217, 257-245, 243-259 and 215-287.
instead, appears more complex where four isomers are
:**
- 1 3-
In Figure 7 is reproduced the isomeric composition of the
acids C 16 - 3.nd C18 - of the oil of virgin olives the isomers
which are most represented, confirming the previous researches
(2), are respectively the cis-9-hexadecenoic and the cis-9-
octadecenoic together with a small quantity of the isomers cis-
11-hexadecenoic and cis-11-octadecenoic0
Figure 7 • Spettrl dl masse del TMSO derived degil este n!
metillel degil acid, grisai monoinsaturl dell'ollo dl olive.
Fig. 7 - Mass spectrums of TMSO derived from the methyl esters of the monounsaturated fatty acids of olive oil.
In Table 1, finally, there is a, representati7e recapitulation
of the isomers of position present in the homologous mono-
unsaturated fatty acids of all the oils examined.
A prusal of the aforesaid data enables us to show that
for acidy with 16 and 18 carbon atoms there predominate largely
the isomers with the double bond in the position 9, 10. The
octadeceno\c acids contain moreover smaller quantities of the
isomer Ai â which does not seem to be a normal nonstituent of
the hexadecenoic acids: this is present in olive oil, but has
not been fo und, for example, in the oil of parsley seeds; in
this last, Inere is Present instead, as we have examined,the
isomer A 6.
The aoids with 20 carbon atoms are comnosed e in a large part,
of the isomer 11 with small qualties of the isomer A 13.
The only tsomer A 13 was found in the acids with 22 carbon atoms.
The position of the double bonds in the monoenic acids ex-
amined so far seems to be in a large measure in accord with the
most recent yiews on the biosynthesis of unsaturated acids. The
formation of every isomer could in fact, be reasonably explain-
ed by the suggested meollanism of enzymatic de-hydroP:enation of
the corresponding saturated acids and the elongation of the
chain by addition of two carbon atoms.
The data reproduced in Table 1 seems to agree with what
has been suggested by Kishimoto and Radin (29), who have pos-
tulated the existence of two distinct de-hydrogenated enzymes,
capable of moving respectively on the positions 6 and 9 from
the carboxyl group of palmitic and stearic acids. These enzymes
i f ie dj CigA,
\ . 8 C2044 C 247 11 CzA9. • tiyAi i
kt‘e I c t
-15-
would ke into account . the formation of the acids cis-6 and
cis-9-exadecenoic, and ois-6 and cis-9-octadecenoic.
:t ma y however be noted that the knowledge on the de-
hydroinated enzymes is still somewhat limited and only from
yeast there has been isolated an enzyme which is capable of
de-hydrogenating the palmitic and stearic acids in position 9
with the formation of the palmitoleic and oleic acids (30).
The mechanism of elongation of the chain - demonstrated with
the help of the composts marked in the case of the monoenic
acids (31) and dienic acids (32) of the sphino-lipids and '
in vitro, with olein CoA (33) - would explain the formation of
the monoenic acids with 20 and 22 carbon atoms and the
isomers cis-11-octadecenoic, according to the following pattern:
„
c mà
c„C
The isomers enclosed in the squares are those formed by
de-hydrogenation of the corresponding saturated acids. It may
be pointed out that this arrangement would take into account
the formation of all the isomers, with the exception of the acids
C16 A 11 9
C20 A 6 and C20 49 for which direct de-hydrogen- ation of the corresponding saturated acid would seem to be the
a b a b a b a b d b• a bla
Cf."
3,3 9,4
C*
c,-
Cie 2,8 9,1
93 83
Ce 3,5 10,2
C 16" 88 100 77 100
ce m
Cie C„« CO"
14,2 à,) 100 83
45 42
13,2 8,5
18,2 6,0 2,5 1,7
9,5 5,8
5,1 3,7 100 89
4,1 3,3
4,2 3,4 •
5,0
12,8 7,8
100 98
90 61 14 18 38 46
100 9S
100 79 99100
100 98
94 100
97 100
100 96
100 93
100 . . '85
1,9 1,1 100 72
4,7 2,6 100.77
M 8,2
answere The acids cis-6 and cis-9-eicocenoic have been found
however, only in the oil of parsley seed.
We would like to point out, finally, that we could find no
trace in this oil àf the acid cis-8-octadecenoic, which should
have resulted .from the addition of a unit of C2 to the acid
cis-6-hexacenoic, while the acid cis-8-eicocenoié is present
and is most likely derived from the acid cis-6-octadecenoic with
a similar mechanism.
TABELLA 1 Table 1 r 6
ogous, Altezze relative del frammenti a e b per grupP1 dl midi Isomeri
hel,ghts of TragmentR R and 11 for groups of _ • ... à0Ljei t
a 1; la b a b Imrermes...1.«.*
Hew
omo. isomerà of acids. loghl àe aè à* en Au
Vegetable oil 011 vegetall
Calm (Drnsmica enmpestrls)
Rapeseed' Prezzeinolo (Petroselinum sntivum)
Parsley Soia (Saki hispida) Soya Oliva (Olea europaea) Olive Lino •
9risnim uitatissimum
&nape (Sinnpis alba)
Mustard:-• Girasole (Helinnthus annuub) ecilils.n flower
'- (7..ea mays)
A rachide (& achis hypogea)
Cattapa (Cannabis sativa) nemp
-17-
Concluslohs:
The method of determining the position of the double bond
in the monoenic acids by means of gascromatography-mass spec-
trometry has been found to be simple and quick to operate and
enables one to wOrk with very small quantities, of one-two mg.
And small quantities of isomers can be readily shown up
when these are present in quantities exceeding or equal to 1%
of the most abundant isomer.
The results obtained have confirmed basically the data
already noted in the literature on the subject, but in some
cases it has been possible to show up the presence of isomers
which were not noted previously, such as the acids cis-6-
hexadecenoici cis-8 and cis-9-eicosenoic in the Pil of parsley
seed, and cis-13-octadecenoic in rapeseed and mustard oils.
The slight variations that are found in the relative in-
tensity of the fragments a and b in the different isomers of
position (23) make it necessary to determine the mass spectrum
of the pure single isomers, other than the standardization of
experimental conditions, when exact quantitative results
are to be obtained..
From an examination of the results obtained by us, it
is possible, nevertheless . , to show with a percentage error of
around 15%, the quantitative rationof the isomers present in
the different aCids,based on the ratio of the height of the main
fragments correaponding to the different isomers on the mass
spectrum.
-18- BILIOGRAPHY:•
B tELTOGRAFIA
1) MAGNEI F. C.: J. Am, 011 Chem. Soc., 42, 332 (1965). 2) KUEIMMEL D. F.: J. Am. Oil Chem. Soc., 41, 667 (1964). 3) Lou G. e PALtorrs U.: Rit'. Ital. Sost. Grasse, 41, 425 (1966).
4) Zoszur C. M. e Csrritri P.: in .corso di stampa. 3) Wt.: RUDLOFF L.:. Catt, J. Citent., 33, 1701 (1955). 6) Vox Rtrot.one L.! J. Am. Oil Chem. Soc.) 33, 126 (1956):
7) Tuaocii A. P. e Casio B. M.: J. Am, Oil Client. Soc., 41, 322 (1964),
8) JONES E. P. e DAVISON V. L.: J. Am. Oil Citent. Soc., 42, 121 (1965).
9) MA1.I.Ako T. M. e CRAIG B. M.: J. Am. Oil' Chem. Soc., 43, 1 (1966).
10) Pluviirr O. S. e NICKELL E. C.: J. Am. Oil Citent. Soc., 43, 393 (1966).
II) amt.: E., CAl'ELLA P. e VALENTINt A.: Rite, liai. Sost. Grasse, 40, 313 (1963).
12) PRIVETT O. S. C NICKELL E. C.: Lipids, I, 166 (1966).
13) ACKMAN R. G.: J. Am. Oil Chem. Soc., 43, 483 - (1 966).
14) RYIIAGE R. e SIENUAGEN E.: Arkiv. Kenti, 13, 523 (1959).
15) RYIIAGII R. e e STENIIAGEN E.: Arkiv. Kenti, 14, 483 (1959).
16) RYIIAGII R. c STENIIAGEN E.: Arkiv. Kent, 15, 291 (1960).
17) Rynnun R. e STENIIAGF.N E.: Arkiv, Kenti, 15, 333 (1960),
18) RYIIAGI: R. e STENIIAGE.N E.: Aikiv. Kemi, 15, 545 (1960).
19) DINII-NGUYEN N., RYIIAGEI R. e STALDERG-STENIIAGEN S.: Arkiv. Kemi, 15, 433 (1960).
20) KENNER G. W. C STENUAGEN E,: Acta Chem. Scand., 18, 151 (1964).
21) AUDIER H., Bon' S., FErnoti M. LONGEVIALLE P. e TOUDIANA
R.: Bull. Soc. Chin:. France, 3034 (1964).
22) MCCLOSKEY J. A. e MCCLELLAND M. J.: J. Am. Chetn. Soc., 87, 5090 (1965).
23) CAPELLA P. e Zoitzur C. M.: Anal. Client., 40, 1458 (1968).
24) . PALLorr* U, e MATARESE Riv. Ital. Sost. Grasse, 41, 210 (1964
• ./
25) WEITKAMP A. W., SMILMNIC, A. M. e Rcrrtimsm S.: J. Am. Chem. Soc., 69, 1936 (1947).
26) JACOO J. e GRINNER G.: J. Lipid Res., 8, 308 (1963).
27) Lam G. e BAZAN E.: La Ricerca Scientilica, 798 (1967).
28) Lorri G. c BAZAN E.: La Ricerca Scientifica, 1005 (1967).
29) Kr.sitisurro Y. e RADIN N. S.: J. Lipid Res., 5, 98 (1964).
30) Elt.00mmun 1). K. e Ewen K.: J. Biol. Citent., 225, 479 (1960).
31) KISIIIMOTO Y. e RADIN N. S.: J. Lipid Res., 4, 414 (1963).
32) MEAD J. F. e Howie: D. R.: Radioisotope Studies of Fatly Acid Metabolism, Pali: 51.56, Pergamon Press, New York, 1960.
33) HARLAN W. R. e WAKIL S..1.1 Blochent. Biophys, Res. Com-num., 8, 131, (1962).
-19-
ITALIAN BIBLIOGRAPHY
3) G. Loi and U. Pallotta: Italian Review of Fatty Substances:
41, 425 (1966).
4) C.M. :,orzut and P. Capella: In Course of Printing.
11) E. Fedeli, P. Cepella and A. Valentini: Italian Review of
Fatty Substances: 40, 313 (1963).
23) P. Capella and C.M. Zorzut: Anal. Chem: 40, 1458 (1968).
24) U. Pallotta and L. Matarese: Italian Review of Fatty
Substances: 41, 210 (1964).
27) G. Lotti and E. Bazan: Scientific Research: 798 (1967).
28) G. Lotti and E. Bazan: Scientific Research: 1005 (1967).
<
-20-
DISCUSSION RECORDED
PRESTDENT: PROF. CANTARELLI (Institute of Agrarian Industries of the University of Perugia).
PRESIDENT
We congratulate most heartily Dr. Zorzut for the excellent
demonstration of an extremely refined technique i which I con-
sider most u-seful since it has a very wide application. The
next time we shall have a direct quantitative tabulation. This
has been a most oriented and extremely interesting paper; and
then there are applications of a biochemical nature which are yet
another horizon that is opening up in relation to this research.
My warm thanks again.
A discussion then took place in which amoniz those takin
2ar_t_mre Prof. Privett Hormel Institute of the University of
Minnesota) and a resumLof which was provided by Prof. Capella:
PROF. CAPELLA (Institute of Agrarian Industries of the Univer-sity of Bologna).
As everybody knows, Prof. Privett has put forward a most
refined method for the determination of the position of the
double bonds by 'means of ozonlysis of the unsaturated acids and
determination by means ofgaschromatography of the fragments that
are obtained by this method. Now according to Prof. Privatt, -
his method has above all the advantage of being a very rapid one
and also à better deal than the method used by us; naturally by
deal I refer to the fact that we must have the mass spectrometer.
-21-
am certinly in agreement with the second of these object-
ions but cannot say the same for the first; our method is
more or less equally rapid and above all the point where we
believe 3ur methoi is different from the method of ozonlysis
is this: we are not forced to proceed with the prior sep-
aration of the homologues present in a complex mixture of fatty
acids in order to study the different isomers of position of
- each homologue.
For example if we have a series from 014 to 0 20 of mono-
unsaturated acids, we can effect a gascromatography of the
derivatives -, take the mass spectrum of each r.,'eak and thus see
in each peak how many isomers and what sort of isomers . are
present.
Naturally, in the method outlined by Prof. .Privett also
which does not provide for the separation by means of chroma-
tography on a thin strata4 but provides instead a separation by
means of liquid - liquid chromeography of the different isomers
which according to him, brings the things to a parity, i.e,
we are forced to effect a chromatoreraphy on a thin strata in
order to separate the monounsaturated acids from the polyunsat-
urated ones and Prof. Privett makes a liquid-liquid chromato-
graph which separates the homologues. Thus, he states we bring
thethings to parity". I belieire that on this position of parity
we can all be satisfied.