Ultraviolet/Visible Spectroscopy (UV-Vis)

Shimadzu UV-3600 UV/Vis Spectrophotometer

UV-Vis Spectroscopy is used for the quantitative determination of different analytes at one given time or over a desired period of time. Analytes include transition metal ions, highly conjugated organic compounds, and biological macromolecules which are usually carried out solutions. The samples are dispensed into a cuvette which is placed in-between the ultraviolet and visible light (UV/Vis) source and a detector. The absorption of light across the UV/Vis wavelengths through the liquid sample is detected and the concentration of the compound in the solution can be determined using Beer-Lambert’s law.

Principle

The Shimadzu UV-3600 covers a wide wavelength range from 185 to 3,300 nm enabling measurements over the ultraviolet, visible, and near-infrared regions and contains three detectors which are a PMT (photomultiplier tube) for the ultraviolet and visible regions and an InGaAs detector and a cooled PbS detector for the near-infrared region. The InGaAs detector is used to cover the crossover between the visible and NIR region which increases the sensitivity and reduce the noise across the entire measured wavelength range. The large-sample compartment and integrating sphere options enable high-sensitivity measurement of solid samples. High-accuracy absolute reflectance measurements can also be performed using a large number of absolute specular reflectance accessories. 

These accessories include an integrating sphere attachment which utilizes diffuse reflectance measurements for the measurements involving solid samples. This method is used as light cannot pass through solid samples. Instead the light is reflected on the surface of samples. This reflected light is of two types; specular reflection and diffuse reflection. Incident light reflected symmetrically with respect to the normal line is called "specular reflection," while incident light scattered in different directions is called "diffuse reflection." As this diffuse reflection can be measured, solid samples can be analysed based on these diffuse reflection measurements.

Strengths

• High Sensitivity - 3 Detector System
• High Resolution - Wide Measurement Range & Ultra-low Stray Light
• Ultra-Low Stray-Light
• Wide Wavelength Range
• Wide Range of Optional Accessories

Limitations

• Cannot perform spectroscopy on gases

Applications

• Polymer industry: Detection of chromophores in polymer samples 
• Pharmaceuticals: Quantitative analysis of active pharmaceutical ingredients in formulations, determination of drug release, detection of impurities in organic materials 
• Textile industry: Anlaysis of the colour properties of textiles, textile chemicals and dyes
• Agriculture: ELemental analysis using colorimetry/ Determination of internal quality of fruits and vegetables.

Technical Specifications

• Photometric System: Double Beam optics
• Wavelength Range: 185 nm – 3,300nm
• Bandwidth: 0.1 nm - 8nm
• Resolution: 0.1 nm
• Scan Speed: 1800 nm/min