Minimizing Urine Autofluorescence Under Multi-photon Excitation Conditions

Authors: Bukowski, Eric J.; Bright, Frank V.

Source: Applied Spectroscopy, Volume 58, Issue 9, Pages 254A-280A and 1023-1140 (September 2004) , pp. 1101-1105(5)

Publisher: Society for Applied Spectroscopy

Buy & download fulltext article:

OR

Price: $29.00 plus tax (Refund Policy)

Abstract:

We report on the effects of excitation wavelength, laser power, and phase resolution on the multi-photon-excited autofluorescence (background) from human urine. When compared to the autofluorescence under one-photon excitation conditions (λex = 260–480 nm), the urine multi-photon-excited autofluorescence (λex = 725–950 nm) can be less complicated. However, at higher laser powers, the multi-photon-excited autofluorescence spectra that are produced by excitation above ~775 nm are more complex in comparison to the corresponding one-photon-excited autofluorescence. The origin of these more complex spectra arises from simultaneous two- and three-photon-driven excitation of intrinsic luminescent species within the urine. At lower laser powers, three-photon-driven processes are minimized and the autofluorescence spectrum is simplified. Phase resolution is used to further minimize the urine autofluorescence, but it cannot fully eliminate autofluorescence even when excitation is performed under multi-photon conditions at 950 nm. For detecting 250 nM Rhodamine 6G (a mock analyte) dissolved in urine, we find that the two-photon excitation is superior in comparison to one-photon excitation by 5- to 70-fold, depending on the excitation wavelength. Phase resolution combined with two-photon excitation leads to an additional 5- to 7-fold improvement in signal-to-background ratios in comparison to steady-state two-photon excitation.

Keywords: AUTOFLUORESCENCE; BIOFLUID; EXCITATION WAVELENGTH; MULTI-PHOTON EXCITATION; PHASE-RESOLVED FLUORESCENCE; URINE

Document Type: Research Article

DOI: http://dx.doi.org/10.1366/0003702041959442

Affiliations: Department of Chemistry, Natural Sciences Complex, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000

Publication date: September 1, 2004

More about this publication?
Related content

Tools

Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content

Text size:

A | A | A | A
Share this item with others: These icons link to social bookmarking sites where readers can share and discover new web pages. print icon Print this page