UV/VIS Autosampler

Fixed wavelength measurements
Fixed wavelength measurements and full scans of UV/Vis spectra are the simplest UV/Vis applications. These can generally be automated with all types of automated sampling.

Quantitative determination
InMotion™ autosamplers are especially suited to quantitative applications that require the determination of a calibration curve before sample analysis, as they allow the measurement of calibration standards and samples in one run.

Temperature control
Applications that require automation of a constant temperature control use either a CuvetteChanger, or an InMotion™ autosampler, depending on the number of samples. If an InMotion™ autosampler is used, it is advisable to use immersion probes instead of flow cells. Samples are thermostated on the autosampler rack with measurements done directly in the beakers. With flow cells, samples must be transferred via noninsulated tubes, causing unwanted temperature fluctuations.

When working with an autosampler, the sample amount available should exceed 10 mL. When working with pumps and autosamplers, more sample is required than when working with cuvettes (e.g., CuvetteChanger). A sample is transferred via tubes to the flow cell, and, therefore tube volume must be filled as well. Additionally, the flow cell must be flushed with the new sample to push out the previous one. If only a small volume of sample is available for analysis (less than 10 mL), then a CuvetteChanger might be the better automation option.

Slightly viscous samples (approximately 20–50 mPas) are not a problem for peristaltic pumps, but as viscosity increases, samples become more difficult to transfer. At the same time, the cleaning and rinsing of flow cells becomes increasingly difficult. This may make CuvetteChanger a better option.

When samples are hazardous or otherwise of safety concern to the operator, sipper pumps and autosamplers are ideal for minimizing operator exposure, as they require fewer interactions. When working with sipper pumps, the operator only needs to insert the aspiration tube in the sample and the pump will do the rest. The risk of sample spillage or accidental contact is reduced significantly. The operator only needs to handle the samples once when loading the rack. After that, the system will take care of transferring, measuring and disposing of samples. Additionally, thanks to a small footprint, InMotion autosamplers can be placed in fume hoods to protect operators further.

Sipper pumps and InMotion™ autosamplers allow optical path lengths from 1 to 50 mm. CuvetteChangers allow the use of optical path lengths of 10 mm or shorter, provided the outer dimensions are 12.5 by 12.5 mm.