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A fluorescent probe for diacetyl detection.

Li X, Duerkop A, Wolfbeis OS - J Fluoresc (2008)

Bottom Line: A water-soluble fluorescent probe, rhodamine B hydrazide (RBH), was prepared and its properties for recognition of diacetyl were studied.The method employs the reaction of diacetyl with RBH, a colorless and non-fluorescent rhodamine B spiro form derivative to give a pink-colored fluorescent substance.In weakly acidic media, RBH reacts more selectively with diacetyl than with other carbonyls, causing a large increase in fluorescence intensity and thereby providing an easy assay for the determination of diacetyl.

View Article: PubMed Central - PubMed

Affiliation: Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany.

ABSTRACT
A water-soluble fluorescent probe, rhodamine B hydrazide (RBH), was prepared and its properties for recognition of diacetyl were studied. The method employs the reaction of diacetyl with RBH, a colorless and non-fluorescent rhodamine B spiro form derivative to give a pink-colored fluorescent substance. In weakly acidic media, RBH reacts more selectively with diacetyl than with other carbonyls, causing a large increase in fluorescence intensity and thereby providing an easy assay for the determination of diacetyl.

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Fluorescence increase of RBH caused by diacetyl or other carbonyls as potential interferents after reaction in pH 3 citrate-phosphate buffer (50 mmol/L) at 37 °C for 3 h. The concentration of diacetyl is 10 μmol/L. For other carbonyls the concentration is 87.5, 65, 60, 100, 50, 136 and 20 μmol/L for glyoxal, methylglyoxal, benzylaldehyde, acetaldehyde, acetoin, acetone and pyruvic acid, respectively
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Fig5: Fluorescence increase of RBH caused by diacetyl or other carbonyls as potential interferents after reaction in pH 3 citrate-phosphate buffer (50 mmol/L) at 37 °C for 3 h. The concentration of diacetyl is 10 μmol/L. For other carbonyls the concentration is 87.5, 65, 60, 100, 50, 136 and 20 μmol/L for glyoxal, methylglyoxal, benzylaldehyde, acetaldehyde, acetoin, acetone and pyruvic acid, respectively

Mentions: The reaction of RBH with various carbonyls was examined under the above conditions to determine the selectivity of the probe for different carbonyls. Ten micromolar per liter of diacetyl and a twice to 13.6-fold molar excess of interferent was reacted with RBH in pH 3 citrate–phosphate buffer solution (50 mmol/L) at 37 °C for 3 h. Then, the enhancement of the emission intensities was compared. Figure 5 indicates that RBH has a much higher selectivity for diacetyl than for other carbonyls, except that benzylaldehyde shows noticeable interference. However, there is no report which shows that benzylaldehyde is found as a result of metabolism in any physiological process. As we aim to find a reagent to determine diacetyl at physiological concentrations, the interference of benzylaldehyde is not relevant for our purposes. Apart from benzaldehyde, pyruvic acid shows interference if it is present at 20 μmol/L. If the emission intensity of pyruvic acid is calculated for the same molar concentration (10 μmol/L) as for diacetyl, however, the signal of pyruvic acid is tenfold lower than that of diacetyl. This 10 μmol/L is the concentration of pyruvic acid one can expect to occur in cell medium [24] or from cell influx and efflux [25]. The selectivity towards other carbonyls on a molar basis varies between 35:1 for glyoxal and 200:1 for acetaldehyde. Although glyoxal and pyruvic acid are more electrophilic compounds than diacetyl and thus should show faster reaction kinetics with RBH, lower emission intensities of the respective reaction products after a reaction time of 3 h are found, reproducibly. We currently do not have an explanation for this phenomenon. Therefore, interferences are unlikely to be a problem for this probe to be applied for diacetyl detection in the cases where diacetyl is the dominant carbonyl species to be determined.Fig. 5


A fluorescent probe for diacetyl detection.

Li X, Duerkop A, Wolfbeis OS - J Fluoresc (2008)

Fluorescence increase of RBH caused by diacetyl or other carbonyls as potential interferents after reaction in pH 3 citrate-phosphate buffer (50 mmol/L) at 37 °C for 3 h. The concentration of diacetyl is 10 μmol/L. For other carbonyls the concentration is 87.5, 65, 60, 100, 50, 136 and 20 μmol/L for glyoxal, methylglyoxal, benzylaldehyde, acetaldehyde, acetoin, acetone and pyruvic acid, respectively
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Related In: Results  -  Collection

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Fig5: Fluorescence increase of RBH caused by diacetyl or other carbonyls as potential interferents after reaction in pH 3 citrate-phosphate buffer (50 mmol/L) at 37 °C for 3 h. The concentration of diacetyl is 10 μmol/L. For other carbonyls the concentration is 87.5, 65, 60, 100, 50, 136 and 20 μmol/L for glyoxal, methylglyoxal, benzylaldehyde, acetaldehyde, acetoin, acetone and pyruvic acid, respectively
Mentions: The reaction of RBH with various carbonyls was examined under the above conditions to determine the selectivity of the probe for different carbonyls. Ten micromolar per liter of diacetyl and a twice to 13.6-fold molar excess of interferent was reacted with RBH in pH 3 citrate–phosphate buffer solution (50 mmol/L) at 37 °C for 3 h. Then, the enhancement of the emission intensities was compared. Figure 5 indicates that RBH has a much higher selectivity for diacetyl than for other carbonyls, except that benzylaldehyde shows noticeable interference. However, there is no report which shows that benzylaldehyde is found as a result of metabolism in any physiological process. As we aim to find a reagent to determine diacetyl at physiological concentrations, the interference of benzylaldehyde is not relevant for our purposes. Apart from benzaldehyde, pyruvic acid shows interference if it is present at 20 μmol/L. If the emission intensity of pyruvic acid is calculated for the same molar concentration (10 μmol/L) as for diacetyl, however, the signal of pyruvic acid is tenfold lower than that of diacetyl. This 10 μmol/L is the concentration of pyruvic acid one can expect to occur in cell medium [24] or from cell influx and efflux [25]. The selectivity towards other carbonyls on a molar basis varies between 35:1 for glyoxal and 200:1 for acetaldehyde. Although glyoxal and pyruvic acid are more electrophilic compounds than diacetyl and thus should show faster reaction kinetics with RBH, lower emission intensities of the respective reaction products after a reaction time of 3 h are found, reproducibly. We currently do not have an explanation for this phenomenon. Therefore, interferences are unlikely to be a problem for this probe to be applied for diacetyl detection in the cases where diacetyl is the dominant carbonyl species to be determined.Fig. 5

Bottom Line: A water-soluble fluorescent probe, rhodamine B hydrazide (RBH), was prepared and its properties for recognition of diacetyl were studied.The method employs the reaction of diacetyl with RBH, a colorless and non-fluorescent rhodamine B spiro form derivative to give a pink-colored fluorescent substance.In weakly acidic media, RBH reacts more selectively with diacetyl than with other carbonyls, causing a large increase in fluorescence intensity and thereby providing an easy assay for the determination of diacetyl.

View Article: PubMed Central - PubMed

Affiliation: Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany.

ABSTRACT
A water-soluble fluorescent probe, rhodamine B hydrazide (RBH), was prepared and its properties for recognition of diacetyl were studied. The method employs the reaction of diacetyl with RBH, a colorless and non-fluorescent rhodamine B spiro form derivative to give a pink-colored fluorescent substance. In weakly acidic media, RBH reacts more selectively with diacetyl than with other carbonyls, causing a large increase in fluorescence intensity and thereby providing an easy assay for the determination of diacetyl.

Show MeSH