Biomark Sensor Research

High Performance Liquid Chromatography (HPLC) is a separation technique that can provide qualitative or quantitative data of a complex mixture. Each component of the sample interacts with the stationary phase material of the chromatographic column in a different manner, leading to a separation of the components of the mixture as they flow out of the column. The equipment that BioMark has is Thermo Scientific’s HPLC Surveyor Plus which is equipped with a UV / Vis detector and an automatic degassing station on top of an automatic sampler. Temperature control at separation of the column is also possible. ============ Electroanalysis consists of the application of electrochemistry in the analysis of the phenomena associated with the separation processes of electric charges. Often this separation of charges leads to charge transfer, which can occur homogeneously in solution, or heterogeneously on the surface of the electrode. Electrochemical measurements may be performed for analytical purposes under equilibrium conditions (zero current) with potentiometric or off- equilibrium (current passing) with amperometric or voltammetric sensors. The instrumentation that the laboratory has for this type of measurements are several benchmark modular potentiostats / galvanostats, which are most of them integrated impedance spectroscopy from AUTOLAB (PGSTAT302N and M204), as well as similar portable equipment from DROPSENS (µSTAT 200) and PALMSENS (EmStat3). These equipment allow connection to conventional three-electrode systems, as well as printed electrode reading boxes and photovoltaic and fuel cells. ============ Atomic force microscopy is an analysis technique that consists of scanning the surface of a sample with a probe in order to obtain its 3D topographic image at the nanoscale, besides mapping certain mechanical and physicochemical properties of the materials that compose them. The laboratory has a hpAFM atomic force microscope from NanoMagnetics Instruments, which can analyze dry or liquid samples using contact, non-contact and dynamic modes, and the use of magnetic force (MFM) and electrostatic force (EFM). ============ Fluorescence spectroscopy, also called spectrofluorimetry, is a type of electromagnetic spectroscopy in which the fluorescence (light emitted) of a sample is analyzed, and this is proportional to the concentration of the compound analyzed. The form of emitted light is almost always longer wavelength than the light absorbed (Stokes’ law). The equipment that BioMark has is the Thermo Scientific Lumina fluorescence spectrometer that can monitor the intrinsic fluorescence of a given sample or fluorescence generated by (bio)chemical reactions, allowing the analysis of highly complex samples with very low detection limits. Powders, films, paper and plastic (among others) can be analyzed with this equipment. ============ Infrared spectroscopy is a type of absorption spectroscopy, in which absorbed energy is found in the infrared region of the electromagnetic spectrum. Like all other spectroscopic techniques, it can be used to identify a compound or investigate the composition of a sample. The term Fourier transform infrared spectroscopy derives from the fact that it is necessary to use the Fourier transform (a mathematical process) to convert the data collected in the radiation spectrum. The laboratory features a Nicolet iS10 FTIR from Thermo Scientific, equipped with an ATR (Attenuated Total Reflection) accessory with diamond and germanium crystals, allowing direct analysis of most samples, without prior preparation in most cases. This equipment can be used to obtain an infrared spectrum of a solid, liquid or gas compound, collecting high spectral resolution data over a wide spectral range, which is particularly useful to follow-up qualitative chemical properties of materials. ============ Raman spectroscopy is an optical inelastic diffusion technique which is sensitive to the low energy vibrational modes of the molecules and provides specific and detailed information about the molecular composition of the samples in a manner complementary to the infrared absorption spectroscopy. In Raman spectroscopy, the physical phenomenon involved is the inelastic radiation scattering, that is, the scattered radiation has energy different from the incident radiation. In general, in Raman spectroscopy, the scattered radiation detected has less energy than the incident radiation (Stokes scattering) and the energy difference between them corresponds to the energy difference between two vibrational levels of the molecule. The intensities of the Raman lines are roughly 0.001% of the intensity of the radiation source, and the Raman effect is therefore an event of low probability and difficult to detect and measure. The equipment that BioMark has is the Thermo Scientific Raman DXR spectroscope that is connected to a confocal microscope system and equipped with two excitation lasers one at 532 nm and another at 780 nm. This equipment also allows the analysis of samples by mapping, which allows the two-dimensional characterization of the samples. The acquisition of maps allows visualizing the spatial distribution of phases (inorganic and organic) in a sample according to defined coordinates. ============ Ultraviolet / visible (UV / Vis) spectroscopy is based on measurements of absorption or reflectance of the electromagnetic radiation in the visible and ultraviolet regions of the electromagnetic spectrum, the amount of light being absorbed or reflected by the sample related to the concentration of the analyte, solid or liquid. The laboratory has a Thermo Scientific UV / Vis Evolution 220 spectrophotometer, which can be used to analyze almost any type of sample. Liquid in plastic, glass or quartz cuvettes. Solids can be analyzed directly using an integrating sphere (samples up to 6 mm × 6 mm are analyzed directly). The equipment can also be coupled to a Peltier thermostated system that allows spectrophotometric measurements with precise temperature control. ============ Thermogravimetry or thermogravimetric analysis (TGA) is a destructive thermal analysis, where the physical and/or chemical properties of the materials are measured as a function of the temperature increase (with constant heating rate) or as a function of time (with constant temperature and / or mass loss) under controlled atmosphere. BioMark is equipped with Hitachi TG / DTA / 7200 equipment that can provide information on physical phenomena, such as second-order phase transitions including vaporization, sublimation, adsorption, absorption and desorption, or on chemical phenomena including desolvation (especially dehydration) , decomposition and solid-gas reactions (eg oxidation or reduction). It can also provide differential scanning calorimetry (DSC) data.