Aneta Bombalska

Comparison of fluorescence spectroscopy and FTIR in differentiation of plant pollens.

Spectroscopic techniques are under investigation on possibility of differentiation of airborne particles. This paper describes pollen discrimination among others bio-particles in laboratory conditions. Pollen samples were characterized with UV-Vis fluorescence, drift and KBr pellet techniques of infrared spectroscopy. Principal Component Analysis of UV-Vis fluorescence and FTIR spectra revealed that pollens can be distinguished from other bio-materials with use of these methods. Both methods resulted in similar classification capability. Combined FTIR and fluorescence data analysis did not improve the discrimination between pollen allergens and other airborne biological materials.

Classification of the biological material with use of FTIR spectroscopy and statistical analysis

Rapid detection and discrimination of dangerous biological materials such as bacteria and their spores has become a security aim of considerable importance. Various analytical methods, including FTIR spectroscopy combined with statistical analysis have been used to identify vegetative bacteria, bacterial spores and background interferants. The present work discusses the application of FTIR technique performed in reflectance mode using Horizontal Attenuated Total Reflectance accessory (HATR) to the discrimination of biological materials. In comparison with transmission technique the HATR is more rapid and do not require the sample destruction, simultaneously giving similar absorbance bands. HATR-FTIR results combined with statistical analysis PCA and HCA demonstrate that this combination provides novel and accurate microbial identification technique.

Application of FTIR and SERS spectroscopy in analysis and discrimination of bacteria and their interferents

In recent years, growing threat of terrorist attacks with use of chemical or biological warfare agents is observed. Biological agents, due to often delayed effects, higher lethality and more difficult detection and identification compared to chemical agents, are especially dangerous. Therefore, rapid detection and discrimination of dangerous biological materials has become a security aim of considerable importance. Various analytical methods, including FTIR spectroscopy combined with statistical analysis have been used to discriminate various bioagents and their background interferents. The applicability for this purpose of another spectroscopic technique, Surface Enhanced Raman Spectroscopy (SERS), has also been intensively investigated in recent years. In this work, the results of the application of FTIR technique performed in reflectance mode using Horizontal Attenuated Total Reflectance accessory (HATR) for discrimination of vegetative bacteria, bacterial spores and background interferents are discussed. Applied technique is shown to be capable of distinguishing between vegetative bacteria, bacterial spores and fungi against other biological specimens. In addition, the results of initial studies on application of plasmonic nanostructures for enhancement of Raman scattering signals of bacterial cells are discussed. Our studies have shown that it is possible to obtain Raman scattering signal from single bacterial cell in presence of single plasmonic nanostructure.

The application of semiconductor based UV sources for the detection and classification of biological material

Fluorescence analysis of dry samples of biological origin like pollens, fungi, flours and proteins was presented. In the laboratory study presentenced here two fluorescence methods using semiconductor light sources were applied. Firstly, laser induced fluorescence emission (LIF) spectra of the samples were recorded under 266 and 375 nm excitation. The second technique covered fluorescence decay (FD) at 280 and 340 nm excitation. Hierarchical Cluster Analysis (HCA) of acquired spectra and decays was performed. Both LIF and FD showed that single wavelength excitation 266 and 280 nm, respectively allow distinguishing of pollens from other samples. Combining data of both excitation wavelengths, for LIF and FD, respectively, resulted in substantial improvement of data classification for groups according to the samples origin.

Fluorimetric techniques in analysis and classification of fuels

In presented work the analysis of liquid fuels with use of optical spectroscopy was performed. The fuels were examined with the use of two fluorescence techniques: steady-state fluorescence and time-resolved fluorescence. Recorded excitation-emission matrices (EEMs), with the use of steady-state fluorescence, allowed for estimation of the absorption and emission maxima, classification of the fuels was partially possible. Time-resolved fluorescence allowed for classification of the fuels into four groups. Among examined fuels the longest time of fluorescence decay was observed in diesel, petrol Pb98 and Pb95, in descending order.

The laser detector of bio-aerosols

In the paper we describe a new construction and preliminary laboratory tests of airborne particle flow detector. The device is designed for continuous monitoring of biological particles in ambient air. The scattering and fluorescence signals from each particle are detected simultaneously. The device uses 375 nm laser for fluorescence excitation. The luminescence is measured with three broad bands. Principal Component Analysis was applied for data analysis. It has been demonstrated proper classification between various biological aerosols.

Optoelectronic methods in potential application in monitoring of environmental conditions

Allergic rhinitis, also known as hay fever is a type of inflammation which occurs when the immune system overreacts to allergens in the air. It became the most common disease among people. It became important to monitor air content for the presence of a particular type of allergen. For the purposes of environmental monitoring there is a need to widen the group of traditional methods of identification of pollen for faster and more accurate research systems. The aim of the work was the characterization and classification of certain types of plant pollens by using laser optical methods, which were supported by the chemmometrics. Several species of pollen were examined, for which a database of spectral characteristics was created, using LIF, Raman scattering and FTIR methods. Spectral database contains characteristics of both common allergens and pollen of minor importance. Based on registered spectra, statistical analysis was made, which allows the classification of the tested pollen species. For the study of the emission spectra Nd:YAG laser was used with the fourth harmonic generation (266 nm) and GaN diode laser (375 nm). For Raman scattering spectra spectrometer Nicolet IS-50 with a excitation wavelength of 1064 nm was used. The FTIR spectra, recorded in the mid infrared1 range (4000-650 cm-1) were collected with use of transmission mode (KBr pellet), ATR and DRIFT.