An Environmentally Friendly Flow Injection-Gas Diffusion System Using Roselle (Hibiscus sabdariffa L.) Extract as Natural Reagent for the Photometric Determination of Sulfite in Wines

Table 3

Sulfite contents in wines as determined by the proposed method and the Ripper method.

Sample number	Sample type	Sulfite concentration (mg L^−1)∗
		Ripper method	Proposed method
1	Sparkling wine 1	24.1 ± 0.2	23.9 ± 0.4
2	Sparkling wine 2	20.3 ± 1.9	19.9 ± 0.2
3	White wine 1	12.9 ± 0.9	12.6 ± 0.7
4	White wine 2	20.6 ± 0.2	20.4 ± 0.5
5	White wine 3	34.7 ± 0.7	34.9 ± 0.3
6	White wine 4	21.5 ± 0.9	22.1 ± 0.2
7	White wine 5	35.5 ± 0.9	34.5 ± 0.3
8	White wine 6	31.7 ± 0.8	30.5 ± 0.1
9	White wine 7	27.3 ± 1.3	23.1 ± 0.3
10	Red wine 1	3.5 ± 0.2	2.28 ± 0.2
11	Red wine 2	8.3 ± 0.1	7.72 ± 0.8
12	Red wine 3	10.6 ± 0.8	10.9 ± 0.2

∗Mean of triplicate results.