Selective optical aqueous and non-aqueous detection of free sulfites
AssigneeThe Research Foundation for The State University of New York
InventorsLynn Schmitt, Alistair Lees
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Abstract
4-pyrrolylpyridine, a novel anion sensor, displays a substantial color loss upon addition of sodium sulfite in aqueous solvents. A variety of anions were tested, including halides, phosphates, sulfates, and hydroxide, but all solutions remained unchanged aside from the sulfite, which displayed bleaching. Described here is a method for which the exact concentration of sulfites in a consumer product can be determined. The test is sensitive over a broad range of sulfites, from 0.84 ppm to over 10,000 ppm, and is accurate with a standard deviation of ±0.01 ppm.
Claims20
A method of detecting a free sulfite in an aqueous analyte, comprising:
- reacting a first amount of the free sulfite in the aqueous analyte, with a compound having a 4-(1H-pyrrol-2-yl)pyridine ligand structure to perform a first bleaching;
- measuring a first optical absorption corresponding to the first bleaching of the compound having the 4-(1H-pyrrol-2-yl)pyridine;
- adding a second amount of the free sulfite in the aqueous analyte with the compound having the 4-(1H-pyrrol-2-yl)pyridine after the first bleaching, to perform a second bleaching;
- measuring a second optical absorption corresponding to the second bleaching of the 4-(1H-pyrrol-2-yl)pyridine;
- and
- calculating the free sulfite concentration in the aqueous analyte based on the measured first optical absorption and the measured second optical absorption.
An apparatus for performing a method for detecting a free sulfite in an aqueous analyte, comprising:
- reacting the free sulfite in the aqueous analyte, with 4-(1H-pyrrol-2-yl)pyridine, having an optical absorption and being subject to bleaching by free sulfite;
- and
- determining a colorimetric change resulting from the reacting, comprising measuring a change of the optical absorption by reaction of the free sulfite in the aqueous analyte with the 4-(1H-pyrrol-2-yl)pyridine,
- the apparatus comprising:
- a spectrometer;
- a fluidic device configured to add the aqueous analyte in a sufficient quantity to bleach the 4-(1H-pyrrol-2-yl)pyridine by 10% at 463 nm;
- and
- a calculation device, configured to determine and output a concentration of the free sulfite in the aqueous analyte based on the bleaching of 4-(1H-pyrrol-2-yl)pyridine determined by the spectrometer.
A method of determining a free sulfite concentration in an aqueous analyte, comprising:
- providing 4-(1H-pyrrol-2-yl)pyridine,
- adding a first amount of the aqueous analyte to the 4-(1H-pyrrol-2-yl)pyridine, and measuring a first bleaching of an optical absorption of the 4-(1H-pyrrol-2-yl)pyridine;
- adding a second amount of the aqueous analyte to the 4-(1H-pyrrol-2-yl)pyridine after the first bleaching, and measuring a second bleaching of an optical absorption of the 4-(1H-pyrrol-2-yl)pyridine, and
- calculating the free sulfite concentration in the aqueous analyte based on at least the second bleaching.
Dependencies are inferred from the claim text.