EXPERIMENT 1.5: PARTICLE SIZE AND SHAPE ANALYSIS USING MICROSCOPE

OBJECTIVE:

To determine the size and general shape of different types of sand under the microscope.

INTRODUCTION:

By using microscope method, it is an excellent technique to determine shape of particles and presence of agglomeration.

There are 3 types, Light microscope, Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM)

Size analysis is carried out on the 2D images of particles which are generally assumed to be randomly oriented in three-dimensions.

METHODOLOGY:

Apparatus and Materials

Light Microscope

Sands ( MCC, 150 µm, 335 µm, 500 µm, 850 µm )

Procedure

1.  Sands are collected from samples and prepared on a microscope slides.
2. 5 different types of sand/powder are analyzed by using a microscope with particular emphasis on the size and shape of the particles.
3. The particles are observed microscopically and sketched.
4. The general shape for the particular material is determined.

RESULTS:

DISCUSSION:

The different particle sizes of sand are observed via light microscope. However, the specimens prepared should be adequately dispersed on the slide to prevent agglomeration that will affect the observation. All the particles observed are in irregular shape .The size analysis is carried out on two-dimensional image of particles which are generally assumed to be randomly oriented in 3-dimensional and they are viewed in their most stable orientation.

QUESTIONS:

1. Explain in brief the various statistical methods that you can use to measure the diameter of a particle.

•    The method used to measure the diameter of a certain particle is the projected perimeter diameter which is based on the circle having the same perimeter as the particle. Next we have projected area diameter which is based on the equivalent area to that of projected image of a solid particle. These two types of measurements are carried out for two-dimensional image using light microscope.

•        For Feret’s diameter that is the mean distance between two parallel tangents to the projected particle perimeter while Martin’s diameter that is the mean chord length of the projected particle perimeter, which can be considered as the boundary separating equal particle area are carried out for measuring three-dimensional image by using electron microscope and considering also the orientation and shape of the image.

2. State the best statistical method for each of the samples that you have analysed.

•        For all materials that we used, the best statically method is Feret’s and Martin’s diameter. It is because both are the statistical diameters which are averaged over many different orientations to produce a mean value for each particle diameter.

CONCLUSION:

Generally MCC particles appear to be smaller than the sand particles. Particles size is important consideration in making a tablet because different particles size will produce pharmaceutical availability, thus affecting pharmacokinetic profile of a drug.

REFERENCES:

Morse,P. & Loxley, A. Drug Delivery Technology. Particle Size Distribution. Light Microscopic Determination of Particle Size Distribution in an Aqueous Gel.

Particle size analysis for microscopy and sedimentation. https://www.youtube.com/watch?v=DV2vUeRT8w8

https://www.youtube.com/watch?v=IW3DPKs6Qj4