High dynamic range in videodensitometry—a comparative study to classic videoscanning on Gentiana extracts (original) (raw)
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Studia Universitatis Babeș-Bolyai Chemia
The combination of high-performance thin-layer chromatography (HPTLC) with image analysis (IA) and chemometrics becomes an attractive tool for natural extracts investigations. The large variability of these samples requires powerful image acquisition devices, multivariate image processing techniques and advanced chemometric methods to facilitate the interpretation of the chromatographic data. In the current study, two image acquisition devices and different image processing procedures were investigated using the HPTLC chromatograms of hydroalcoholic extracts of Gallium verum. Different sets of chromatographic data were generated for both UV chromatograms (obtained at 254 nm and at 366 nm) using images acquired with a digital camera and an UV-Vis TLC scanner. In all cases the Principal Component Analysis (PCA) technique was used in order to extract the information from chromatographic profiles. Variables of gray and pure colour red, green and blue intensities of pixels from start to front were used as input data in all cases. The results obtained by PCA investigations of HPTLC data from UV chromatograms at 254 nm and 366 nm respectively, provided complementary information related to the characteristics of the investigated extracts. Moreover, important steps as appropriate color scale selection and image processing/analysis procedures were pointed out based on the obtained results.
Quantitative evaluation of chromatograms from totally illuminated thin-layer chromatographic plates
Journal of Chromatography A, 1997
Saccharose in fermented and non-fermented soybean flour was determined by thin-layer chromatography. A comparison was made between quantification of TLC plates with CCD camera, with classical densitometry and by scanning with a small slit. In the last case the signal response of such a slit represents the signal from one pixel, which means that scanning with camera was simulated. All the measurements were made in reflectance and in transmission mode. The results obtained with a charge-coupled device camera have a linear correlation between response area and concentration of saccharose within a higher concentration range than the densitometrically obtained results. The linearity of calibration curves was better in transmission than in reflectance mode.
The start-to-end chemometric image processing of 2D thin-layer videoscans
Journal of Chromatography A, 2011
The purpose of the research was to recommend a unified procedure of image preprocessing of 2D thin layer videoscans for further supervised or unsupervised chemometric analysis. All work was done with open source software. The videoscans saved as JPG files underwent the following procedures: denoising using a median filter, baseline removal with the rollerball algorithm and nonlinear warping using spline
2013
Microanalysis of transfer (Trace) evidence is the application of a microscope and microscopical techniques for the collection, observation, documentation, examination, identification, and discrimination of micrometer sized particles or domains. Microscope spectrophotometry is the union of microscopy and spectroscopy for microanalysis. Analytical microspectroscopy is the science of studying the emission, reflection, transmission, and absorption of electromagnetic radiation to determine the structure or chemical composition of microscopic-size materials. Microscope spectrophotometry instrument designs have evolved from monochromatic illumination which transmitted through the microscope and sample and then is detected by a photometer detector (photomultiplier tube) to systems in which broad-band (white light) illumination falls incident upon a sample followed by a non-scanning grating spectrometer equipped with a solid-state multi-element detector. Most of these small modern spectrometers are configured with either silicon based charged-couple device detectors (200-950 nm) or InGaAs based diode array detectors (850-2300 nm) with computerized data acquisition and signal processing being common. A focus of this research was to evaluate the performance characteristics of various modern forensic (UV-Vis) microscope photometer systems as well as review early model instrumental designs. An important focus of this research was to efficiently measure ultraviolet-visible spectra of microscopically small specimens for classification, differentiation, and possibly individualization. The first stage of the project consisted of the preparation of microscope slides containing neutral density filter reference materials, molecular fluorescence reference materials, and dichroic reference materials. Upon v completion of these standard slide preparations analysis began with measurements in order to evaluate xiii APPENDX I. SPECTRAL DATA FOR CRAIC TECHNOLOGIES QDI 2010 SYSTEM 1………....………153 APPENDIX II. SPECTRAL DATA FOR CRAIC TECHNOLOGIES QDI 2010 SYSTEM 2…….………….161
Enhanced imaging of developed fingerprints using mass spectrometry imaging
The Analyst, 2013
Latent fingermarks are invisible to the naked eye and normally require the application of a chemical developer followed by an optical imaging step in order to visualize the ridge detail. If the finger deposition is poor, or the fingermark is aged, it can sometimes be difficult to produce an image of sufficient quality for identification. In this work, we show for the first time how mass spectrometry imaging (in this case time-of-flight secondary ion mass spectrometry, ToF-SIMS) can be used to enhance the quality of partially recovered fingermarks. We show three examples of how chemical imaging can be used to obtain enhanced images of fingermarks deposited on aluminium foil, glass and the handle of a hand grenade compared with conventional development techniques.
Biotechnological applications of image analysis: present and future prospects
Journal of Biotechnology, 1992
The current and potential biotechnological applications of image analysis and image processing systems are reviewed. Image analysis systems have proven to be highly versatile and efficient tools for assisting academic biotechnological research. It is expected that image analysis systems will allow more rapid and accurate quantification of numerous biotechnological analyses. There is, therefore, much scope for the implementation of image analysis/processing systems in a large variety of industrial and clinical applications.
Microplate Based Pathlength Correction Method for Photometric DNA Quantification Assay
2012
This technical note describes how to use a simple photometric pathlength correction method to calculate nucleic acid concentrations from sample absorbance measured on a microplate with the Thermo Scientifi c Multiskan GO spectrophotometer. Pathlength correction normalizes absorbance values measured on a microplate to correspond to absorbance values measured in a standard cuvette. The liquid pathlength in a standard cuvette is 1 cm, whereas the liquid pathlength in a microplate is not fi xed. On microplates the absorbance is measured vertically through the well, so several factors affect the liquid pathlength and thus the absorbance. Therefore in photometric microplate measurements pathlength correction is required for calculating the DNA/RNA concentrations directly from the absorbance values. For example, A260nm 1.0 of dsDNA measured at a 1 cm pathlength corresponds to a concentration of 50 μg/ml. This known multiplication factor together with the automatic pathlength correction in ...
2018
This paper presents the automation of the thin-layer chromatography technique whose separation and identification of molecules present in a mixture are currently done manually and laboriously [1]. We have therefore found an interest in automating this technique. In this part, the method implemented comprises 2 steps. First we proceeded to the segmentation of the spots obtained on the chromatographic plate. We then developed a program to identify families of molecules such as coumarins, terpenes, tannins, flavonoids, polyphenols, etc. by calculating segmentation parameters such as standard deviation, entropy, average pixel intensity from an algorithm on the matlab software. Finally our results have been compared to the results obtained by the traditional identification technique in laboratories. Some similarity between the two results obtained shows the reliability and the robustness of our technique.