Malvern Mastersizer 3000 User Manual

Chapter 5 Viewing measurement results
Page 5-12 MAN 0474
residual of over 1% may indicate use of incorrect refractive index and absorp-
tion values for the sample and dispersant.
 The statistics of the distribution are calculated from the results using the
derived diameters D[m,n] – an internationally agreed method of defining the
mean and other moments of particle size. See British standard BS2955:1993 for
more details.
Dv 50, Dv 10 and Dv 90 are standard percentile readings from the analysis.
 Dv 50 – the size in microns at which 50% of the sample is smaller and 50%
is larger. This value is also known as the Mass Median Diameter (MMD)
or the median of the volume distribution. The v in the expression Dv 50
shows that this refers to the volume distribution. This can be replaced by s
for surface, l for length or n for number distributions.
 Dv 10 – the size of particle below which 10% of the sample lies.
 Dv 90 – the size of particle below which 90% of the sample lies.
 D[4,3] – the Volume Weighted Mean or Mass Moment Mean Diameter,
also known as the De Broucker mean.
 D[3,2] – the Surface Weighted Mean, also known as the Surface Area
Moment Mean Diameter or Sauter mean.
 Span – is the measurement of the width of the distribution. The narrower the
distribution, the smaller the span becomes. The span is calculated as:
The x is replaced by any of the letters v, s, l or n that define the distribution
type.
 Concentration – the volume concentration. This is calculated using Beer-
Lambert’s law. For full details see the following section.
 Obscuration – this helps the user to set the concentration of the sample when
it is added to the dispersant. It is a measure of the amount of laser light lost due
to the introduction of the sample into the analyser beam.
The obscuration term can be expressed mathematically:
Dmn
V
i
d
i
m 3–

V
i
d
i
n 3–

---------------------------
1
mn–
-------------
=
Span
dx0.9dx0.1–
dx0.5
------------------------------------------------
=

Malvern Mastersizer 3000 Specifications

General

Measurement principle	Laser diffraction
Blue laser wavelength	470 nm
Sample dispersion options	Wet and dry dispersion
Data acquisition rate	10 kHz
Particle size range	0.01 to 3500 microns
Laser type	He-Ne and solid state
Accuracy	Better than 1%
Repeatability	Better than 0.5%
Technology	Mie and Fraunhofer theories
Sample dispersion units	Hydro MV, Hydro LV, Aero S
Optical model	Mie theory
Power requirements	100-240 V, 50/60 Hz
Detector arrangement	Log-spaced array