Reetaleena RISSANEN¹, Ilpo NISKANEN^2*, Jukka Räty³, Pirjo Kyyrönen³, Asta LEINONEN³, Risto Myllylä⁴, and Kai-Erik PEIPONEN⁵

¹Finnish Institute of Occupational Health, FI-53850 Lappeenranta, Finland
²Thule Institute, University of Oulu, FI-90014 Oulu, Finland
³CEMIS-OULU, University of Oulu, P. O. Box 51, FI-87101 Kajaani, Finland
⁴University of Oulu, Optoelectronics and Measurement Techniques Laboratory, P. O. Box 4500, FIN-90014, Oulu, Finland
⁵Institute of Photonics, University of Eastern Finland, P. O. Box 111, FI-80101 Joensuu, Finland

(Received September 18, 2013; Accepted December 16, 2013)

We have built a novel optical multi-sensor apparatus (MSA) for the measurement of light absorption, scattering and fluorescence either separately or simultaneous from a liquid. From the measured data it is possible to calculate different optical properties of liquid samples, such as absorbance and turbidity. The MSA is a portable device which is an advantage considering different field applications. The MSA was tested in laboratory conditions using well-known reference liquids. Data obtained with the MSA were compared with data obtained with a commercial spectrophotometer, fluorometer and a nephelometer, respectively. Relatively good correlations between the data of MSA and the three commercial devices were found. It is proposed that MSA is a potential device for monitoring changes of process liquids and liquid products in industry.

Key words: multi-sensor, transmission, scattering, fluorescence, liquid

^*E-mail address: ilpo@niskanen@oulu.fi