New A-TEEM Ultrafast Molecular Fingerprinting Technique

The patented Aqualog, a compact benchtop fluorometer from HORIBA Scientific, is the only instrument to contemporaneously measure both absorbance spectra and fluorescence Excitation-Emission Matrices (EEMs) corrected for the inner filter effect (IFE) in real-time.

All colored molecules exhibit unique molecular absorbance and transmittance spectra; many colored molecules also exhibit unique fluorescence excitation and emission spectra that can be measured as an excitation-emission matrix (EEM).

Simultaneously combining Absorbance–Transmission and EEM (A-TEEM), is a new technique that provides a distinct molecular fingerprint of complex chemical mixtures and the identification of their components with high specificity and ultrahigh-sensitivity. Aqualog uses a TE-cooled CCD fluorescence detector for rapid fluorescence data acquisition, and a double-grating excitation monochromator for stray-light rejection, combining to make Aqualog up to 4,000 times faster than traditional PMT-based fluorometers. In fact, A-TEEM fingerprints molecules with simultaneous absorbance, transmission, and IFE-corrected fluorescence at a rate of 6 million nm/minute. Thus, A-TEEM’s acquisition and analysis timeframe takes seconds to minutes, versus other techniques and procedures that may take hours to weeks!

A key patented feature and capability of Aqualog is its automatic Inner Filter Effect (IFE) correction. The IFE correction is meant to compensate for both the Primary Inner Filter Effect (PIF), where the excitation light intensity is gradually diminished due to absorption as a function of the optical pathlength of the liquid sample before reaching the fluorescent volume and the Secondary Inner Filter Effect (SIF) where the emitted fluorescence intensity is diminished due to reabsorption even by the portion of the sample that is not excited directly by the excitation beam.

With A-TEEM and Aqualog, one is able to apply key multivariate analysis methods to identify, quantify and understand dynamics of molecules and mixtures. A-TEEM identifies and quantifies single molecules and mixtures, protein conformation and aggregation changes, product adulteration, and the effects of aging, oxidation, and contamination. The instrument is suited to water quality research and monitoring, wine constituent analysis, protein purity, and vaccine quality assurance applications. A-TEEM has already proven in many cases to be more effective in these applications than HPLC and traditional vibrational spectroscopy.

Read our white paper on EPA Stage 2 Disinfection Compliance or check out our webinar on ‘Assessing the Capability of Spectroscopy Techniques to Evaluate Water Quality’.