HSP, a mighty tool for formulation applications Application note
Executive summary
Field of applicationsFormulation | Pharmaceutical industry | Cosmetics | Inks | Food Industry | Lubricant
Many practical chemical products are actually formulations, i.e. sophisticated mixtures of numerous compounds that can be liquids or solids.
How to select them e!ciently without costly and time-consuming tests?
Hansen Solubility Parameters (HSP) are one of the most used prediction tools to perform such selections. The HSP define the material properties in three dimensions, the disperse, the polar and the hydrogen-bonding properties ( , and ), which are used by formulators to predict the compatibility of com-pounds in mixture. However, the HSP of most compounds are not known and can be di!cult to determine, especially for liquids. Indeed, their values are often not measured experimentally but rather computed on theoretical basis.
In this application note, we show how Inverse Gas Chromatography (IGC) is able to measure the HSP of liquid substances by testing their interaction ability toward 20 di"erent solvents. Our method makes it possible to perform the HSP measurement within a day (including reproducibility tests for each solvents) and using reduced material and solvents amounts. Moreover, the generated IGC data can be imported and directly processed by the HSPiP software used by groups around the world to optimize formulations via HSP techniques. This method can easily be applied to oils, surfactants, polymers above Tg and any liquid additives. As an example, two liquids were analyzed: Olive Oil and PEG400.
Principle
Examples
Objectives
Th
e pu
rpo
se here is to
dem
on
strate the ab
ility of th
e Inverse G
as Ch
rom
atog
raph
y (IGC
) to d
etermin
e the
Han
sen So
lub
ility Param
eters (HSP
). HSP
analysis is a p
ow
erful an
d p
ractical way to
better u
nd
erstand
issues
of so
lub
ility, disp
ersion
, di"
usio
n, ch
rom
atog
raph
y and
mo
re [1]. In th
is app
lication
no
te, two
liqu
id-b
ased
materials, o
live oil an
d P
EG4
00
, are used
as an exam
ple to
express th
e po
tent ad
vantag
es of su
ch tech
niq
ue
for th
e determ
inatio
n o
f HSP.
Th
e Han
sen So
lub
ility Param
eters (HSP
) were in
i-tially d
evelop
ed b
y Ch
arles M. H
ansen
in 19
67 as
a too
l for p
redictin
g if o
ne m
aterial will d
issolve in
an
oth
er and
form
a solu
tion
. Tod
ay, they are w
idely
used
to p
redict ch
emical co
mp
on
ent co
mp
atibili-
ties in m
ixture an
d to
accelerate the d
evelop
men
t o
f form
ulatio
ns o
f inks, p
aints, ad
hesives, co
smetics
or p
harm
aceuticals. H
SP d
ivide th
e total so
lub
ility p
arameter (
) into
three in
divid
ual p
arts arising
fro
m d
ispersio
n fo
rces betw
een m
olecu
les (),
energ
y from
dip
olar in
termo
lecular fo
rces betw
een
mo
lecules (
), and
hyd
rog
en-b
on
din
g (
). T
he H
SP d
etermin
ation
s can b
e achieved
by in
verse g
as chro
mato
grap
hy at in
finite d
ilutio
n co
nd
ition
s (IG
C-ID
) [2, 3, 4] co
mb
ined
with
the H
SPiP
softw
are d
evelop
ed b
y Pr. Steven
Ab
bo
tt, Dr C
harles H
ansen
an
d D
r Hiro
shi Yam
amo
to [5, 6
]. Ad
scientis d
eve-lo
ped
, the N
euro
nic so
lutio
n, a m
etho
d to
measu
re th
e HSP
of liq
uid
sub
stances. In
oth
er wo
rds, 20
m
olecu
lar pro
bes (so
lvents) are in
jected at very
low
con
centratio
n in
a stainless-steel co
lum
n filled
w
ith th
e sub
stances to
be in
vestigated
coated
on
to
a suitab
le packin
g m
aterial. Th
eir retentio
n tim
e is m
easured
. Th
e surface o
f the su
pp
ort n
eeds to
b
e fully co
vered (15%
-20%
in w
eigh
t). Hen
ce, it is
Th
e net reten
tion
time (
) of each
pro
be
(, w
ith
the reten
tion
time o
f the
peak o
f the p
rob
e and
th
e retentio
n tim
e of a
no
n-retain
ed p
rob
e like meth
ane).
Th
e specific reten
tion
volu
me (
) derived
from
th
e b
y the fo
llow
ing
equ
ation
:
(1)
With
th
e measu
remen
t temp
erature in
,
th
e corrected
carrier gas flo
w an
d
the w
eigh
t o
f dep
osited
samp
le.
Ch
emical co
mp
on
ent co
mp
atibilities are cru
cial param
eters need
ed b
y inks-, p
aints- ad
hesives-, co
sme-
tics- and
ph
armaceu
ticals- ind
ustries an
d acad
emic lab
s. Two
liqu
id m
aterials are con
sidered
: olive o
il and
P
EG4
00
. To p
rovid
e go
od
, accurate an
d rep
rod
ucib
le data, A
dscien
tis has d
efined
a tho
rou
gh
pro
cedu
re for
the d
etermin
ation
of th
e HSP. Fo
r that, th
e liqu
id m
aterial was d
epo
sited o
n th
e chro
mato
grap
hic statio
nary
ph
ase in a th
ick layer by an
imp
regn
ation
meth
od
. For th
at step, it is im
po
rtant to
ob
tain a h
om
og
eneo
us
coverin
g an
d th
ick eno
ug
h layer o
f the ch
rom
atog
raph
ic sup
po
rt by th
e liqu
id m
aterial. Th
e HSP
values can
b
e determ
ined
at amb
ient o
r hig
her tem
peratu
re dep
end
ing
on
the p
hysical state o
f the su
bstan
ces to b
e in
vestigate (liq
uid
, pasty o
r solid
).
Th
e HSP
measu
remen
ts by IG
C-ID
on
olive o
il an
d P
EG4
00
are achieved
at 25 °C. T
he sam
e set o
f twen
ty pro
be m
olecu
les is injected
on
bo
th
samp
les. Each m
olecu
le is ind
ividu
ally injected
several tim
es to m
easure a m
ean valu
e and
a stan-
dard
deviatio
n o
f their reten
tion
time (
). Eq
uatio
n (1) w
as then
used
to co
mp
ute th
e cor-
respo
nd
ing
specific reten
tion
volu
me (
) of each
p
rob
e. Th
ese values w
ere directly u
sed to
com
pu
te th
e HSP
values w
ith th
e HSP
iP so
ftware.
Th
e softw
are first com
pu
tates the exp
erimen
tal Flo
ry-Hu
gg
ins in
teraction
param
eter () [1, 3, 6
]. T
he H
SP co
mp
on
ents o
f the sam
ple, (
), () an
d
() are th
en calcu
lated u
sing
an iterative m
etho
d.
Th
is iterative meth
od
aims at m
aximizin
g th
e co
rrelation
coe!
cient (
) fit value b
etween
expe-
rimen
tal an
d calcu
lated
values b
ased o
n th
e “d
istance” b
etween
the H
SP valu
es of th
e pro
bes
and
the cu
rrent estim
ate HSP
values o
f the sam
ple.
Th
e algo
rithm
uses all th
e available p
rob
es to co
m-
pu
te the
, an
d
values th
at are best fittin
g th
e exp
erimen
tal valu
e.
Th
e final reg
ression
grap
hs fo
r the co
mp
utatio
n
of th
e three co
mp
on
ents o
f PEG
40
0 an
d o
live oil
are also d
on
e on
the co
mp
lete set of so
lvents u
sed
as pro
bes. T
he co
mp
utatio
n o
f the th
ree HSP
of
PEG
40
0 an
d O
live Oil are resp
ectively sho
wn
on
Fig
ure 3 (to
p) an
d Fig
ure 3 (b
otto
m). T
he b
est fitting
H
ansen
Solu
bility p
arameters o
f PEG
40
0 an
d o
live o
il com
pu
ted w
ith th
e HSP
iP so
ftware are g
athered
in
Table 1.
Samp
le
PEG
40
021.1
10.2
8.4
0.9
44
Olive o
il17.0
0.3
4.10
.96
1
Parameters and softw
are to be used for the HSP determ
inations:
General scope:
Results:
assum
ed th
at the su
pp
ort d
oes n
ot co
ntrib
ute to
th
e pro
be’s reten
tion
time. T
his m
etho
d m
akes it p
ossib
le to p
erform
the H
SP m
easurem
ent w
ithin
a d
ay (inclu
din
g rep
rod
ucib
ility tests for each
sol-
vents) an
d u
sing
on
ly small am
ou
nts o
f material an
d
solven
ts. With
this m
etho
d, w
e measu
re a mean
valu
e and
a stand
ard d
eviation
of th
eir retentio
n
time (
). Th
e specific reten
tion
volu
me (
) is then
d
erived fro
m th
e retentio
n tim
e () an
d can
be
directly im
po
rted in
to th
e HSP
iP so
ftware.
Th
e HSP
iP so
ftware p
rovid
es the alg
orith
m an
d
com
pu
tation
meth
od
for th
e HSP
determ
ina-
tion
s. Probe
InjectionAdsorption/Desorption
Detection
Studied substancesEluted peak
Retention time
Studied liquid sample
coated on supportSupport
Experimental
-2-1
01
23
4-2 -1 0 2 41 3
Calculated
-2-1
01
23
4-2 -1 0 2 41 3
IGC: PEG
400
IGC: O
live Oil
Experimental
Calculated
Signal ( )
Time (m
in)
Hexane probeHeptane probe
Octane probe
0
0.2
0.4
0.8
1.0
050
100150
200250
300
HexaneHeptane
Octane 3 measurements
0 1 2 3 54
(cm3)
0.56 0.01+
1.58 0.04+
4.35 0.11+
Figure 1 Principle of IGC-ID
Figure 3 Example of HSP com
putation forPEG400 (top) and Olive Oil (bottom
)
Table 1 HSP measured at 25°C for both sam
ples(given in M
Pa1/2)
Figure 2 Reproducibility of measurem
ents on 3different probes (Std. dev. < 2.5%
)»
1, rue Alfred KastlerParc SécoiaF-68310 Wittelsheim
www.adscientis.comTél. : +33 3 89 48 00 42Fax : +33 3 89 48 09 63
ConclusionsThis short note demonstrates the ability of Inverse Gas Chromatography to determine accurately the Hansen Solubility Parameters of two liquid mate-rials: olive oil and PEG400. This method has great flexibility as it can obviously be extended to any kind of non-volatile liquid materials. Hence, IGC is a direct and rapid technique, needing really small quantities of products, to determine the HSP with good reproducibility and accuracy.
Furthermore, its combination with the HSPiP com-putation software makes it a powerful tool to obtain information on the compatibility of a liquid material with another. Finally, within a day, the specific re-tention time of 20 molecular probes can be deter-mined by IGC and computed in the software for the calculation of the HSP. We expect this method to hasten and improve significantly the ability to for-mulate intelligently new materials formulation.
Customers
Contact
Dr. Ralf DUMPELMANNTel: +41 62 873 13 [email protected]
Dr. Jo!rey HUVEBusiness ManagerTel: +33 3 89 48 00 [email protected]
For Germany, Austria and Switzerland:
ref 1. C. Hansen, Hansen Solubility Parameters: A user’s handbook, Second Edition. 2007, Boca Raton, Fla: CRC Press
ref 2. IGC-ID sheet, Adscientis
ref 3. S. Abbott, IGC Science: Principles and Practice, 2018
ref 4. https://www.adscientis.com
ref 5. https://www.stevenabbott.co.uk/practical-chromatography/hsp.php
ref 6. https://www.hansen-solubility.com/HSPiP/
References