Issue 19, 2014

Low cost referenced luminescent imaging of oxygen and pH with a 2-CCD colour near infrared camera

Abstract

A low cost imaging set-up for optical chemical sensors based on NIR-emitting dyes is presented. It is based on a commercially available 2-CCD colour near infrared camera, LEDs and tailor-made optical sensing materials for oxygen and pH. The set-up extends common ratiometric RGB imaging based on the red, green and blue channels of colour cameras by an additional NIR channel. The hardware and software of the camera were adapted to perform ratiometric imaging. A series of new planar sensing foils were introduced to image oxygen, pH and both parameters simultaneously. The used NIR-emitting indicators are based on benzoporphyrins and aza-BODIPYs for oxygen and pH, respectively. Moreover, a wide dynamic range oxygen sensor is presented. It allows accurate imaging of oxygen from trace levels up to ambient air concentrations. The imaging set-up in combination with the normal range ratiometric oxygen sensor showed a resolution of 4–5 hPa at low oxygen concentrations (<50 hPa) and 10–15 hPa at ambient air oxygen concentrations; the trace range oxygen sensor (<20 hPa) revealed a resolution of about 0.5–1.8 hPa. The working range of the pH-sensor was in the physiological region from pH 6.0 up to pH 8.0 and showed an apparent pKa-value of 7.3 with a resolution of about 0.1 pH units. The performance of the dual parameter oxygen/pH sensor was comparable to the single analyte pH and normal range oxygen sensors.

Graphical abstract: Low cost referenced luminescent imaging of oxygen and pH with a 2-CCD colour near infrared camera

Supplementary files

Article information

Article type
Paper
Submitted
02 May 2014
Accepted
02 Jul 2014
First published
03 Jul 2014
This article is Open Access
Creative Commons BY license

Analyst, 2014,139, 4924-4933

Author version available

Low cost referenced luminescent imaging of oxygen and pH with a 2-CCD colour near infrared camera

J. Ehgartner, H. Wiltsche, S. M. Borisov and T. Mayr, Analyst, 2014, 139, 4924 DOI: 10.1039/C4AN00783B

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements