Sulfite Determination by a Biosensor Based on Bay Leaf Tissue Homogenate: Very Simple and Economical Method

Figures & data

Figure 1.  The effect of temperature on the biosensor response. [Tris-HCl buffer, 50 mM, pH 8.5. Catechol and sulfite concentrations were injected to a final concentrations of 200 µM. The response obtained at temperature of 30°C was set to 100%].

Figure 2.  The effect of pH on the biosensor response. [Tris-HCl buffers, 50 mM and pH 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5. Catechol and sulfite concentrations were injected to a final concentrations of 200 µM. The activity at pH 8.5 was set to 100% in each buffer, T:30°C.].

Figure 3.  Calibration curve for sulfite. [Measurements were done in Tris-HCl buffer, 50 mM, pH 8.5, 35°C. Catechol concentration was used as 200 µM].

Figure 4.  Thermal stability of the biosensor. [Measurements were done in Tris-HCl buffer, 50 mM, pH 8.5, 35°C. Catechol and sulfite concentrations were used as 200 µM].

Figure 5.  pH stability of the biosensor. [Measurements were done in Tris-HCl buffer, 50 mM, pH 8.5, 4°C. Catechol and sulfite concentrations were used as 200 µM].

Figure 6.  Operational stability of the biosensor. [Working conditions: Catechol and sulfite concentrations were injected to a final concentration of 200 µM. Measurements were done in Tris-HCl buffer, 50 mM, pH 8.5, 35°C.]

Table 1. Sulfite analysis in some real samples by the biosensor and by the enzymatic reference method [27]

	Found sulfite (mg/ml)
Sample	Reference^a	Biosensor	% Relative error
Pickle water 1	1.52	1.6	+5.2
Pickle water 2	1.61	1.6	−0.6
Pickle water 3	1.57	1.6	+1.9

^aMean of three determinations.

Cohen H.J., Fridovich I. Hepatic sulfite oxidase. Purification and properties. J. Biol. Chem. 1971; 246: 359–365

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