Chromogenic Sensing of Biogenic Amines Using a Chameleon Probe and the Red−Green−Blue Readout of Digital Camera Images

Abstract

We report on sensing spots containing an amine reactive chromogenic probe and a green fluorescent (amine insensitive) reference dye incorporated in a hydrogel matrix on a solid support. Such spots enable rapid and direct determination of primary amines and, especially, biogenic amines (BA). A distinct color change from blue to red occurs on dipping the test spots into a pH 9.0 sample containing primary amines. BAs can be determined in the concentration range from 0.01 to 10 mM within 15 min, enabling rapid, qualitative, and semiquantitative evaluation. In the “photographic” approach, the typically 4-7.5-fold increase in fluorescence intensity of the probe at 620 nm along with the constant green fluorescence at 515 nm of a reference dye are used for quantitation of BAs. The sensing spots are photoexcited with high-power 505 nm light-emitting diodes (LEDs) in a black box. A digital picture is acquired with a commercially available digital camera, and the color information is extracted via red-green-blue (RGB) readout. The ratio of the intensities of the red (signal) channel and the green (reference) channel yields pseudocolor pictures and calibration plots.

Reactivity of a luminescent “off–on” pyrylium dye toward various classes of amines and its use in a fluorescence sensor microtiter plate for environmental samples

“…Deposition of a cocktail of Py-1 and Hypan at the bottom of each well (Section 2.3) converts a conventional microplate into a high-throughput sensing tool for the rapid and parallel quantitation of primary amines. The suitability of this cocktail has been shown previously [16] for test stripes for amine sensing.…”

High-throughput sensing microtiter plate for determination of biogenic amines in seafood using fluorescence or eye-vision

“…These LODs are 6-70-fold lower than those found recently for sensing stripes. 34 For a CE method, 19 the linear range was from 0.11 to 11.1 mg mL À1 for all biogenic amines (Table 2), with similar correlation coefficients (ranging from 0.979 to 0.995). While the lower limit of the linear range is comparable to that of the sensing plate, the plate can reach concentrations up to 5-fold higher (of histamine) than CE.…”

“…Histamine is the major degradation product formed during aging of seafood. [34][35][36] Hence, it was regarded to mostly contribute to the signal change detected in the sensing plate. Therefore, the BA content found in the real samples was related to the histamine concentration and was expressed in equivalents of histamine, similarly, as was done by others.…”

Classification and quantitative optical analysis of liquid and solid samples using a mobile phone as illumination source and detector

“…While inexpensive electronic components in consumer products do not approach the quality necessary for use in commercial analytical instrumentation, they have demonstrated usability for optical measurements despite their limitations [2,3]. Reports of the use of digital cameras for chemical analyses, for example, have recently covered such diverse areas as detection of biogenic amines [4], pH [5], water hardness [6,7], nickel in meteorites [8] and alloy composition [9].…”

“…The strategy employed in this approach was to relate the desired analytical parameter to one of the red, green or blue (RGB) color channels (or in some cases employment of a greyscale 2 conversion) in order to obtain quantitative information. Reagent mediated analyses have been extensively studied in which digital images describing color development of one-shot sensing spots were evaluated [4,6,8,10]. There has also been work done using digital images of solutions based on their spectral properties [11][12][13][14][15][16].…”