Real-Time Spectroscopy Setup

A system for detecting and analyzing light absorption/reflection from a sample in real-time, providing crucial information for understanding processes like photocatalysis.

A light source emitting a wide range of wavelengths, crucial for capturing all spectral information, unlike traditional UV/VIS sources.

A camera that directly captures dispersed light spectrum from a grating, eliminating the need for a traditional slit and improving efficiency.

The size of the opening that controls the amount of light entering the setup, impacting spectral resolution and signal-to-noise ratio.

The ability of the setup to distinguish between different wavelengths of light, crucial for detailed analysis in spectroscopy.

The ratio of useful signal strength to background noise in the data.

A chemical reaction that is accelerated by light.

Variations in the properties of a sample across different locations.

A visual representation of how a material's absorbance changes at different wavelengths over time.

The process of breaking down the dye methylene blue (MB) into simpler compounds.

Tiny particles of titanium dioxide (TiO2) that act as photocatalysts, accelerating chemical reactions when exposed to light.

The speed at which a substance breaks down under the influence of light and a photocatalyst.

Differences in the properties of a sample across different locations.

The amount of TiO2 used influences the rate of photocatalytic degradation.

Too much photocatalyst can hinder the reaction, leading to lower efficiency.

The decomposition of a compound by light.

The breaking apart of the benzene ring structure in a molecule.

The ability to capture events at very short time intervals, like a high-speed camera.

Variations in the maximum intensity of light absorption/reflection at different wavelengths during a reaction.

A standard technique for analyzing light absorption/reflection, but limited in temporal resolution.

Real-time spectroscopy provides detailed information about reaction mechanisms that conventional methods miss.

Samples with different components distributed unevenly, like a heterogeneous solution.

The breakdown of methylene blue molecules over time, as observed by a decrease in their absorbance at 603 nm.

The absorbance peak at 662 nm represents the absorption of light by the benzene ring's π-π bonds, specifically due to the sulfur and nitrogen atoms.

Real-time spectroscopy allows detailed observation of chemical reactions, including peak shifts and new peak formation, providing information not available in single measurements.

Changes in the wavelength at which a substance absorbs light, indicating chemical reactions or changes in the substance's structure.

The step-by-step process by which a substance breaks down, as observed by changes in absorbance over time.

The size of the slit opening controls the amount of light entering the setup. A narrow slit provides high spectral resolution but weak signal, while a wide slit gives strong signal but low resolution. Finding the right balance is key for good data.

Unlike traditional methods that take multiple measurements and calculate results, real-time spectroscopy allows for simultaneous detection of light absorption and chemical reactions happening in real time.

A broadband light source shines through the sample and is dispersed by a grating. A CMOS camera directly captures the spread-out spectrum, showing wavelength variations. The camera acts like a detector, unlike traditional setups with a slit.

Contour maps show both spectral and spatial information. The X-axis represents wavelengths, and Y-axis represents the position across the light source. This reveals how light intensity varies across the surface.

Laser filters with known wavelengths are placed to mark specific locations on the contour maps, allowing for accurate pixel-to-wavelength conversion.

Calibration is done by comparing the spectrum of the setup to a known reference sample (didymium glass) with characteristic peaks. This ensures accurate wavelength measurements.

The setup measures the light passing through a sample and divides it by the light measured without the sample. This ratio gives the absorbance spectrum, highlighting how much light the sample absorbs at different wavelengths.

The quality of the spectra obtained is limited by the camera's capabilities, such as frame integration time and frame rate. Higher frame rates require trade-offs with signal strength.

The sampling rate is how often the system records data, measured in frames per second (fps). Faster frame rates allow for more detailed observation of rapid processes.

The position of a peak in the absorbance spectrum reveals the specific wavelength at which the sample absorbs light most strongly. This is crucial for identifying substances.

The setup uses a known relationship between the position of a pixel on the camera and the corresponding wavelength of light. This is derived from the calibration with laser filters.

Bandpass filters allow for selecting a specific range of wavelengths to study, focusing on the desired region of the spectrum and improving signal quality in that region.

Photocatalysis uses light to accelerate chemical reactions, particularly in breaking down pollutants. The real-time setup is useful for monitoring these processes.

The setup allows real-time monitoring of changes in the absorbance spectrum during photocatalysis, providing valuable insights into the degradation of pollutants and efficiency of the process.