ATTENUATED TOTAL REFLECTION PROBE For In-Line UV-Vis Measurement

INTRODUCTION

The high-throughput, rugged ATRP (Attenuated Total Reflection Probe) (Fig. 1) is ideal for use in an industrial process environment with the EquiSpec IPS (In-line Process Spectrophotometer). It can operate at temperatures from -30°C to 280°C and at pressures up to 82 bar (1200 psi). This outstanding performance is achieved by using Kalrez® O-ring seals.

The ATR Probe is a three-bounce design that affords a total path length of approximately 1.5 microns with a sapphire crystal. The sapphire allows response down to 250 nm in samples with an index of refraction up to 1.5, and offers excellent resistance to chemical attack. Cubic zirconia may be used in samples with an index of refraction up to 1.9. The fibers emerge from the probe’s rear in PVC-coated stainless steel armor. If needed, the armor can be sealed with Teflon® for high-temperature operation. An eight-inch extension tube is added to the probe’s rear to allow direct insertion into a process stream. The extension tube can be adapted to the customer’s process connection requirements.

The ATR probe analyzes highly absorbing chromophores such as dyes and aromatic compounds (FIG. 2), minimizing or avoiding the need for diluting solvents making the technique ideal for continuous in-line analysis.

In the pharmaceutical industry, the EquiSpec IPS used with an ATR probe can provide real-time information on the crystallization process of active pharmaceutical ingredients (API), a critical step to ensure such process’s chemical and physical properties. Other applications for UV-Vis ATR spectroscopy are cleaning validation, dissolution rate testing, and reaction monitoring. 

In the paper industry, the technique has been used to analyze hydroxide, sulfide, and carbonate in kraft liquors.

Optical

Physical