Light scattering measurements for quantifying biological cell concentration: an optimization of opto-geometric parameters

An experimental study was carried out, aimed at optimizing the optical/geometrical configuration for measuring the concentration of biological cells by means of static light scattering measurements. A LED-based optoelectronic setup making use of optical fibers was experimented, as the precursor of a low-cost device to be integrated in instrumentation for cytometry. Two biological sample types were considered as test samples of the most popular analyses – cervical cells and urine, respectively. The most suitable wavelengths and detecting angles were identified, and calibration curves were calculated

Optical spectral signatures of liquids by means of fiber optic technology for product and quality parameter identification

Absorption spectroscopy in the wide 200-1700 nm spectral range is carried out by means of optical fiber instrumentation to achieve a digital mapping of liquids for the prediction of important quality parameters. Extra virgin olive oils from Italy and lubricant oils from turbines with different degrees of degradation were considered as ‘case studies’. The spectral data were processed by means of multivariate analysis so as to obtain a correlation to quality parameters. In practice, the wide range absorption spectra were considered as an optical signature of the liquids from which to extract product quality information. The optical signatures of extra virgin olive oils were used to predict the content of the most important fatty acids. The optical signatures of lubricant oils were used to predict the concentration of the most important parameters for indicating the oil’s degree of degradation, such as TAN, JOAP anti-wear index, and water content

Array of opto-chemical sensors based on fiber-optic spectroscopy

A compact, flexible platform for reading out the variation of the optical absorption spectra in the visible range in a number of sensing materials is illustrated in this paper. This apparatus is based on an integrated spectrophotometer, an array of suitably controlled LEDs, optical fibers to carry and collect light, and a mechanical arrangement that makes possible the measurement, in sequence, of up to 15 different sensing layers. The unit was tested with a number of metalloporphyrins, known for their outstanding sensorial and optical properties. Data were analyzed using a multiway chemometrics approach. In this regard, a methodology to investigate the properties of an array of chemical sensors is introduced. This approach allowed an evaluation of the role played in the array by each sensing material in each spectral region to be performed. The analysis revealed interesting insight into the classification properties of the sensor array and the interaction mechanisms of porphyrins. The set of metalloporphyrins showed a variety of interaction mechanisms, and the relation of these mechanisms to the structure of the metalloporphyrins was evidenced by an accurate interpretation of the loadings of the multiway analysis