Download CERTIFICATE OF HIGHER EDUCATION IN COSMETIC SCIENCE

CERTIFICATE OF HIGHER EDUCATION
IN COSMETIC SCIENCE
DIPLOMA IN COSMETIC SCIENCE
Paper One
Date: 7th September 2012
Time: 2.30 pm to 4.30 pm
INSTRUCTIONS TO CANDIDATES
Answer FOUR questions. Start each question on a new page to aid marking.
Write your DLC STUDENT NUMBER, PAPER NUMBER and QUESTION NUMBER on
the top of each sheet. Do not write your name on the paper. Do not write on
the back of the paper. Do not write in pencil.
PAPER ONE
1.
Answer all parts:Personal care and cosmetic formulations, whether they are cleansing or
cosmetic products, are often referred to as colloidal systems. They are
comprised of particles (solids or liquids) dispersed in an incompatible
medium. An input of energy is often required to create the dispersion.
a) Using the second law of thermodynamics as a guide, explain with the
aid of a diagram the energy changes that occur over time for
a colloidal dispersion.
( 5 Marks)
Note: The second law of thermodynamics may be expressed by the
following equation:
G =  A -TS
Where G is the change in the free energy of the system,  is the
interfacial tension, A is the amount of new interfacial area created, T
is the temperature and S is the entropy change.
b) What are the most likely kinetic pathways to instability for an
aqueous solid dispersion (slurry)?
( 2 Marks)
c) With the aid of a free energy diagram, explain how you would
stabilise the colloidal dispersion. Give two examples of how this
could be achieved.
( 6 Marks)
d) Linear block copolymers (surfactants) comprised of alternating
hydrophobic and hydrophilic groups are often used to stabilise
the dispersion. Describe how the polymer can adsorb onto the
surface of the particle and which conformation provides optimum
stabilisation.
( 4 Marks)
e) Describe how the steric hindrance mechanism is able to stabilise
the dispersion?
( 6 Marks)
f) Give two examples of the potential disadvantages provided by
this method.
( 2 Marks)
PAPER ONE
2.
Answer all parts:The urinary system is the principal means by which metabolic
waste is removed from the body.
a) List the organs which make up the urinary system and
briefly describe their roles. You may include a diagram
to illustrate your answer.
( 5 Marks)
b) Describe the processes involved in the manufacture of urine.
Relate these processes to their location in the nephron.
( 8 Marks)
c) As one of the major roles of the urinary system is the
maintenance of fluid and electrolyte balance within the body,
urine volume varies according to the levels of hydration.
Describe how aldosterone and antidiuretic hormone act
to regulate the amount of urine produced.
( 8 Marks)
d) Why would you not expect to find red blood cells in the urine?
If blood is present what might this indicate?
( 4 Marks)
3.
Answer all parts:a) Most of the natural gums are derived from naturally occurring
plants or their seeds usually by aqueous extraction. Give examples
of five natural gums used in the cosmetics industry and their natural
origin.
( 5 Marks)
b) Name three main commercial types of Carrageenan. What
are the primary differences that influence their properties. ( 6 Marks)
c) Suggest a thickener used in the manufacturing of the following
three products giving reasons as to why you have made your
suggestions:i) Toothpaste
ii) Skin Cream/Lotion
iii) Shampoo
( 9 Marks)
d) What major rheological property would you expect magnesium
aluminium silicate (MAS) gels to have. Give an example of the
application area of MAS gels.
( 5 Marks)
PAPER ONE
4.
Answer all parts:The following gas chromatogram (Figure 1) shows the separation of
standards of free fatty acids (FFAs) using a medium polar stationary
phase. Further details of the separation are given in Table 1. Use
your knowledge of chromatography to answer the questions.
Column:
Deactivated polyethylene
glycol
Column:
Deactivated polyethylene
(PEG), wax coated.
glycolo(PEG), wax coated
Temperature: 145
145
o C, isothermal
Temperature:
C, isothermal
Carrier
gas:
Hydrogen
Carrier gas:
Hydrogen
Flowrate:
rate:
min
Flow
5 5mlml/ /min
Detector:
Flame
ionisation
Detector:
Flame ionisation detector
detectorvol: 1 μl
Injection
Injection vol: Split
1 μl50:1;block temp
Injection:
o
Injection:
Split
250
C 50:1;block temp
250oC
1 acetic acid
6 n-valeric acid
acetic acid
n-valeric acid
21propionic
acid 76isocaproic
acid
2
propionic
acid
7
isocaproic
3 isobutyric acid 8 caproic
acidacid
acid 9 heptanoic
8 caproic
43n-isobutyric
butyric acid
acid acid
4
nbutyric
acid
9
heptanoic
5 isovaleric acid
acid
5 isovaleric acid
Table 1
Conditions of separation
Figure 1
Chromatogram of free fatty acids
a) Describe the type of chromatography carried out and why the
components separated under these conditions.
( 6 Marks)
b) Briefly describe how the components were detected after
eluting from the column.
( 3 Marks)
c) Suggest an alternative mobile phase.
( 1 Mark )
d) What is the retention time of n-valeric acid?
( 1 Mark )
e) Approximately what volume of mobile phase would have passed
through the column when isocaproic acid eluted?
( 2 Marks)
f) Comment on the resolution of normal (n) and isomeric (iso)
forms of the fatty acids.
( 3 Marks)
(continued overleaf)
PAPER ONE
4.
(continued)
g) Which component has the highest boiling point and explain
your selection?
( 3 Marks)
h) Assuming that you will carry out a survey of FFAs in oil samples
using this technique, what precautions would you take to ensure
that the results obtained were accurate and precise?
( 6 Marks)
5.
Answer all parts:a) Differentiate between monosaccharides, disaccharides and
polysaccharides.
( 3 Marks)
b) Give two biologically significant examples of each.
( 6 Marks)
c) Explain how monosaccharide molecules can be joined
together to form polysaccharides.
( 6 Marks)
d) Give a brief description of the uses of carbohydrates in
biological systems.
6.
(10 Marks)
Answer all parts:Fatty alcohol ethoxylates are an important group of non-ionic
surfactants used in cosmetic and personal care formulations.
The hydrophobes (fatty alcohols) are obtained from both
natural (fats and oils) and synthetic (petrochemicals) feedstocks.
a) Using fatty alcohols as a starting point, describe the process
used to manufacture alcohol ethoxylates. What are the
advantages and the disadvantages of the process?
( 8 Marks)
b) Detergency is described as the process to remove oily soils
such as sebum and particulates from substrates (skin or hair).
It can be broken down into four main steps. Briefly describe
the mechanisms involved in the presence of a surfactant.
( 4 Marks)
(continued overleaf)
PAPER ONE
6.
(continued)
c) Oily soil removal can be described by the roll back mechanism. The
process is determined by the interfacial tensions acting on the soil
(oil droplet) and its influence on the contact angle formed by the
droplet with the substrate. The forces acting on the oil droplet are
described by the Young equation.



OS, OL and SL are the respective interfacial tensions of the oil in
contact with the substrate, the oil in contact with the liquid and the
solid in contact with liquid.
Discuss the significance of the equation to the wetting of the substrate
by the wash liquid (water) and the spreading properties of the oil
droplet on the surface of the substrate. In your answer make consideration of the relevance of the contact angle to the removal of
the oil droplet from the substrate. What conditions must be met in
order for the oily soil to detach from the substrate?
( 8 Marks)
d) Although non-ionic surfactants are able to penetrate soils, they are
often used in conjunction with ionic surfactants to provide optimum
cleaning performance. Describe the mechanism for an anionic/nonionic mixed surfactant system to detach a particulate soil (solid) from
the surface of the substrate.
( 5 Marks)
PAPER ONE
7.
Answer all parts:a) Draw a fully labelled diagram of a bacterial cell, including
annotations of the functions of the parts labelled.
( 8 Marks)
b) What do you understand by the term binary fission in terms
of microbial growth?
( 4 Marks)
c) State and discuss the factors that can influence the growth
of microorganisms and how these can be used to control
their growth.
(13 Marks)
8.
Answer all parts:a) Describe the chemical structure of a natural oil and a
basic silicone oil, including diagrams of the structures.
(14 Marks)
b) For the silicone oils state the most common grades and
how they differ.
( 2 Marks)
c) In the formulation development of a premium skin care
emulsion you are allowed to use both natural oils and
silicones. Give examples of two natural oils and one
silicone oil and explain their roles in your emulsion.
( 6 Marks)
d) What are the potential hazards of using natural oils in
an emulsion and how can you avoid these hazards?
( 3 Marks)