Date:20/11/2014
Title
Particle Size and Shape
Analysis using Microscope
Objective
To analyze and
interpret the shape of particles and to observe and compare the size of
particles under microscope.
Introduction
Usually, in handling
and processing operations in many powders the size of particle plays important
key role in determining the bulk properties of the powder. Powders’ particles
have many range of sizes and shapes and each of them different to each other.
Determine the size of particles is really important in achieve an optimum
production of efficacious medicines.When synthetizing and formulating a
medicine, the particle size of the drug and other powder is determined because
this willinfluences the subsequent physical performance of the medicine and the
pharmacological of the drug. In order to obtain an equivalent and accurate
diameter, there are a few methods in analyzing and interpreting the size of
particle. One of them is by using the microscope. The size, shape, surface area
and arrangement of the particles can be analyzed by using this method. In this
experiment, various type of sands ( 150µ, 355µ, 500µ, 850µ, mixed ) and two
different powders ( MCC and lactose ) are given to be analyze.
Materials
Sands( 150µ, 355µ,
500µ, 850µ, mixed )
Lactose powder
MCC powder
Apparatus
Microscope
100 ml beaker
Spatula
Glass slide and cover
slip
Procedure
1. Sands with sizes of 150µ, 355µ, 500µ,
850µ, mixed, lactose and MCC are put in the different beakers using spatula.
The beakers are labelled according to the content.
2. The microscope was set up and ready to
be use.
3. 150µ sand scattered on the glass slide
and covered with the cover slip.
4. The sand was observed under the
microscope using 4x100 magnification.
5. The particles were observed
microscopically and the shape was determined.
6. Steps 3 to 5 were repeated by using
355µ, 500µ, 850µ, mixedsands, lactose and MCC powder.
Result
Various sizes sand
The sand under the microscope is various in sizes and has different
colour. The size of the sand is not fixed and has different shapes. Most of the
sand has shape edges.
150 mic
The sand under the microscope all has almost same size. They are all
small size with different shapes and different colour.
355 mic
The sand under microscope all has almost the same size. Although they
have different shapes, all of them have shape edges.
500 mic
Sand with 500 mic has bigger in size. They have almost the same size but
different colour. Their shapes are different with many sharp edges.
850 mic
Sand with 850 mic has the biggest size compare to others. We can see it
easily and clearly under microscope, though they have different size and
colour. But they have shape edges and some of them are slightly transparent.
Lactose
The size of lactose is very fine. The shape of lactose cannot be seen
clearly under microscope.
MCC
The size of MCC is very fine, the size cannot be observed easily under
the electronic microscope.
Questions
Explain in brief the various statistical methods that you can use to
measure the diameter of particle.
The particle that has same size of sphere
with same diameter is known as mono-size. However, most of the sand consists of
different size and shape. The size of distribution can be broken down into
different size ranges. The
frequency which can be presented using histogram or cumulative frequency form
is used to present the size of distribution of size of sand. There will be
three types of result shown by the histogram which are normal distribution,
positively skewed distribution and bimodal distribution. The cumulative
frequency usually used to indicate the undersize of oversize sand.
The know the mode and median diameter of the
particle size, it still can be obtained from the incomplete particle size
distribution while the mean can only be obtained through the complete particle
size distribution with the upper and
lower limit known. There are several ways to determine the particle size. One
of the ways is by using Arithmetic mean. Arithmetic mean can be calculated by
summating a particular parameter for all the individual particles in a sample
and dividing the value achieved by total number of particles. The next way is
Geometric mean. It follows a log-normal distribution. The last one is interconversion
mean. It can be obtained by using Hatch-Choate equations.
2. State the best statistical method for each
of the samples that you have analysed.
The best statistical method
is by using histogram.
DISCUSSION
In this experiment ,it can
be seen that the sands have various shapes and sizes.The sizes of the sands
increases from the 355 µm, 500 µm, to 850 µm
respectively. It is also can be seen that the shapes of the sands are
irregular,rough surfaces and has sharp edges.While the lactose has similar and
small size.Lactose also exhibit regular shapes and it is seen mostly to be
round and do not have sharp edges.
To observe the shapes and sizes of
the sands and lactose,we use microscope which can
magnify and resolute the image.Microscope is a valuable instrument
inlaboratory.We put the sample of particle on a slide and observe it under the
microscope. Light traveling up from the mirror
passes through the glass slide, specimen, and cover slip to the objective lens (the one closest
to the object). This makes the first magnification: it works by spreading out
light rays from the specimen so they appear to come from a bigger object. In
this experiment,we use low power objective (10X), one of the shortest objective
lenswhich is probably the most useful lens for viewing slides. The low power objective is always safe to use
as it cannot be lowered to the point of contacting and thus possible breaking a
slide.
By far the most
important physical property of particulate samples is particle size. Particle
size measurement is routinely carried out across a wide range of industries and
is often a critical parameter in the manufacture of many products. Particle
size has a direct influence on
material properties
such as reactivity or dissolution (catalyst,paints),stability in suspension
(sediment) and appearance(powder coating and inks).Measuring particle size and
understanding how it affects your products and processes can be critical to the
success of many manufacturing businesses.
As
well as particle size, the shape of constituent particles can alsohave a
significant impact upon the performance or processing of particulate materials.
Many industries are now also making particles shape measurements in addition to
particle size in order to gain a better understanding of their products and
processes. Some areas where particle shape can have an impact include
reactivity and solubility (pharmaceutical activities),powder flow and
handling(drug delivery system) and texture and feel (food ingredients).Particle
shape can also be used to determine the state of dispersion of particulate
materials, specifically if agglomerates or primary particles are present
Conclusion
In a conclusion, different
type of sand has different shape and size. They have one similarity which is
most of them having shape edges. All of them have irregular shape. Hence,
granulation is very important to ensure the drug can flow smoothly in
pharmaceutical industry.
REFERENCES
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