1070-4272/02/7503-0427$27.00C2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 3, 2002, pp. 427! 431. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 3,
2002, pp. 438!442.
Original Russian Text Copyright + 2002 by Klenin, Ivanova.
OF CHEMISTRY AND TECHNOLOGY
Spectroturbidimetric Determination of the Size
and Concentration of Terrestrial Particles in Potable Water
V. I. Klenin and N. A. Ivanova
Chernyshevsky Saratov State University, Saratov, Russia
Received October 12, 2001
Abstract-A method was proposed for determining the average size and mass-space concentration of ter-
restrial particles in potable water from the turbidity spectrum. This method was applied to a systematic study
of a formazine suspension and potable water samples.
Turbidity of water is due to the presence of terres-
trial particles having a colloidal degree of dispersion.
At the present time, GOST (State Standard) 33513
74  is acting in Russia, which prescribes photomet-
ric determination of terrestrial particles, with a for-
mazine suspension (prepared from hexamethylene-
tetramine and hydrazine sulfate) as the reference.
The reaction goes to completion, which gives us infor-
mation about the formazine content in a unit volume
of the reaction medium. Several reference suspensions
of different concentrations are prepared and their op-
tical densities D are measured on an FEK-56 photo-
colorimeter with a light filter (l = 540 nm) in 5-cm
cells. The reference cell contains double-distilled
water. The calibration plot of D vs. the formazine
suspension concentration C,mgdm
, is constructed.
From this plot, the concentration of terrestrial particles
in potable water samples is determined. A similar
method for determining the terrestrial particle concen-
tration is practiced abroad . This method cannot be
treated a priori as a correct one, as the turbiidity of
colloidal systems is not only a linear function of the
concentration but also a complex function of the rela-
tive size (size-distribution pattern) and of the relative
refractive index of the particles.
Light scattering theories describe the turbidity of a
colloidal monodisperse system by the equation 
t = N
Here, t is the turbidity, cm
is the number of par-
ticles in cm
, r is the particle radius, K(a, m) is the
light scattering efficiency factor as a function of the
relative size a and the relative refractive index m:
m = m
m is the refractive index of the dispersed phase, m
the refractive index of the dispersion medium, and
l is the wavelength in vacuum.
The procedure prescribed by GOST  does not
allow for the particle size and the difference between
parameters for formazine and terrestrial par-
The aim of this work was to elucidate the poten-
tialities of the spectroturbidimetric method as applied
to determining the mass-space concentration and the
size of terrestrial particles in potable water.
The spectroturbidimetric method showed a good
performance in characterizing dispersed systems of
different nature , in particular, in analyzing mineral
suspensions in natural water basins . For the latest
data concerning disperse systems of different origin,
see monograph .
We found no explanations in published papers and
patents why specifically formazine suspension was
chosen as the reference for analysis of terrestrial par-
ticles in potable water. Thus, we began with studying
the properties of the formazine suspension prepared
according to the GOST mentioned .
Next, we systematically studied potable water
samples by the spectroturbidimetric method and by
the method prescribed by the GOST. Water samples
were taken in various stages of purification, namely,
Our study was concerned with potable water from the water
supply systems in Saratov and Saratov oblast.