Thursday, July 2, 2015

Variable Bandwidth Monochromators: A Useful tool for Quantifying Fluorescent Probes in Produced Effluent Water

Produced effluent water is one of the primary waste products of the process of separating oil, gas and water and is typically a mixture of formation and injection process water containing oil, salts, chemicals, solids and trace metals. Stringent environmental regulations require producers to monitor oil content in water streams from oil production and refining. To further reduce the level of crude oil released in produced water streams, more advanced methods are necessary to accurately detect minute traces of oil in purified samples; down to parts per million (ppm) or parts per billion (ppb) levels.

Several reference methods have historically been used by the industry to measure oil in produced water. These include infrared absorption, gravimetric, and gas chromatography and flame ionization detection (GC-FID) methods. However, none have been universally adopted, and all are subject to limitations. Newer methods, which incorporate a fluorescent probe, overcome the limitations of each of the previously listed methods, and also deliver a high level of sensitivity. Fluorescent probes can also be used to monitor other pollutants, provided that the dye molecule has a high partitioning coefficient into the contaminant.

Sample 201 Exitation-Emission Scan

BioTek’s new Synergy™ Neo2 Multi-Mode Reader has a monochromator-based detection system that can scan and record excitation and emission spectra for fluorescent probes used in produced effluent water, such as those shown above for the unknown sample 201. The spectra provide the basis for optimizing wavelength and bandwidth selection, using the excitation and emission variable bandwidth monochromators in Synergy Neo2. With Gen5 Software, multiple parameters can be tested in the same experiment, setting excitation and emission values at the determined spectral peaks, or off the peak in order to lower potential crosstalk.

excitation and emission values

The sensitivity of each parameter combination can then be assessed by examining calculated signal to noise and limit of detection (LOD) values.

The results of the complete set of reads confirm that the flexibility of the variable bandwidth monochromators on the Synergy Neo2 provide the most ideal parameters to easily detect trace crude oil levels and other potential pollutants in effluent water streams. We invite you to learn more about this application, as well as the Synergy Neo2, by following the link to read the entire application note.

By: BioTek Instruments, Brad Larson, Principal Scientist

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