Granulometric analysis

Granulometric analysis

Particle size analysis by laser diffraction (particle size distribution)

Laser diffraction

Laser diffraction method is used for analysis of powers, suspensions, emulsions and aerosols to determine particles dispersion by size, which is also called particle size distribution.

Новації |

Laser diffraction

Laser diffraction method is used for analysis of powers, suspensions, emulsions and aerosols to determine particles dispersion by size, which is also called particle size distribution.
Understanding of particle size and of the way dispersion by size influences the properties of final and interim product as well as the course of technological process, can be essential for successful production, starting from its development stage. For instance, in pharmaceutical industry particle size and particle size distribution are key qualitative and technological characteristics, as they directly influence reactive capacity of AI, speed of dissolution and, consequently, bioequivalence, fluidity, stability etc. Also determination of particle size distribution with the help of laser diffraction method allows quick and accurate identification of differences between batches of product and raw materials, studying and control of technological process influence on particle size change, identification of sinters and uncharacteristic impurities.

Laser diffraction method is standardized and complies with the following international standards:

  • ISO 13320:2009 Particle size analysis – Laser diffraction methods/
  • US pharmacopoeia: USP <429> Light Diffraction Measurement of Particle Size
  • European pharmacopoeia: ER 2.9.31 Particle size analysis by laser light diffraction
  • DFU 2.9.31. Particle size determination by laser light diffraction

Equipment and measuring principle

Laser diffraction analyser that we use to perform measurements (Bettersizer 2600, Bettersize Instruments), is equipped with running measuring cuvette and module for particles dispersion in liquids and dry dispersion of particles by compressed air. Analyser Bettersizer 2600 allows to measure particles sized 0.02 to 2600 mcm.

Depending on sample quantity, particle size and physico-chemical properties, is dispersed either in the air or in liquid. Liquid dispersion of sample requires insoluble particles, so dispersant is selected in accordance with solubility properties. A laser ray in measuring cuvette passes through dispersed sample, and as a result light emission is diffracted by particles present in sample. The angle of light scattering (He-Ne-laser) depends on particle size, so received diffraction image of the laser is measured and correlated with particle size distribution on the basis of Fraunhofer diffraction or Mie theory. Mie theory application requires knowing of optical properties of dispersion environment, namely: Value of refractive index (RI) and coefficient of light absorption (A) of particle material, as well as value of refractive index of dispersant. If such information is unavailable, these parameters can be established by searching reference databases or defined with the help of new refractive index measuring functions of Bettersizer 2600 analyser, which easily resolves the problem of analysing samples with unknown optical properties.

EquipmentBettersizer 2600
Dispersion modulesLiquid- BT-802,
Aerial- BT-902, BT-902
Means of dispersionLiquid or dry (aerial)
Range of particle size0.02 - 2600 mcm (liquid dispersion)
0.1 - 2600 mcm (dry dispersion)
Sample quantity required for testing*

(*without taking into account sample used for method development or probation)
10 - 500 mg (liquid dispersion)
0.5 - 10 g (dry dispersion)
лазерна дифракція | Новації

Materials, which particle size analysis you can order (powders, suspensions, emulsions, aerosols):

  • Active ingredients an finished medicinal products
  • Cosmetic and hygienic products
  • Household chemicals
  • Food
  • Cement, gypsum, mortars
  • Soil, sand and other minerals
  • Fireproof and isolating materials
  • Pigments, composite materials and fillers
  • Ceramics
  • Powder metals
  • Catalysts
  • Pesticides, plant protection products
  • Mineral fertilizers
  • Hydrocarbon fuel

Sample testing procedure

Analytical method is always developed prior to measuring. At the Client’s choice we usually offer to conduct an approbation of applicability of method presented by the Client or to develop a method of measuring by full cycle, in accordance with requirements of international guidelines and standards, including method verification and validation.

Advantages of particle size measuring in our laboratory

  • We offer individual plan of sample analysis, taking into account regulatory requirements of the industry on analysis of certain materials, requirements on representative sampling, the required time frame, your other requests.
  • We conduct a series of repeated measurements to ensure compliance to requirements on quality of measurements.
  • Analytical method of measuring can be either transferred (taken from another laboratory or equipment) or developed in our laboratory and validated to confirm selectivity, correctness, accuracy, linearity, limits of definition and robustness.
  • The analysis is conducted with the help of modern equipment (Bettersizer 2600, Bettersize Instruments) by the most qualified and experienced specialists in Ukraine, who possess the highly specialized theoretical knowledge.
  • A shortened or detailed report with protocols of measuring is provided on the results of sample analysis.
  • By request our research engineers can interpret the results of analysis and provide the Client with a detailed report.
  • If necessary we offer to conclude a confidentiality agreement.

Typical representation of results of particle size distribution analysis, performed by laser diffraction

If you have found a spelling error, please, notify us by selecting that text and pressing Ctrl+Enter.

Spelling error report

The following text will be sent to our editors: