I hope anyone can help me with this I am doing an experiment to analyze and dete

Question

I hope anyone can help me with this

I am doing an experiment to analyze and determine the sulphite in the dried fruit by using ion chromotography

when I analyzed the standards and the fruit samples , I always get two peaks one at retintion time 14 min and the other one at 16 min, the instrocture told me that one of them for sulphite and the other one for sulphate , and he said I got two peaks due to something related to the PH

my question is, how is the PH related to getting two peaks , and why I got sulphate with sulphite ?

Also, I dilted the standards and friut samples with NaOH

Explanation / Answer

Sulfites occur naturally in all wines to some extent. Sulfites are commonly introduced to arrest fermentation at a desired time, and may also be added to wine as preservatives to prevent spoilage and oxidation at several stages of the winemaking. Sulfur dioxide (SO2) protects wine from not only oxidation, but also from bacteria. Without sulfites, grape juice would quickly turn to vinegar.

Organic wines are not necessarily sulfite-free, but generally have lower amounts and regulations stipulate lower maximum sulfite contents for these wines. In general, white wines contain more sulfites than red wines and sweeter wines contain more sulfites than dried ones.

Some times sulfate also found in very small amount...there is a rapid transformation of sulfite to SO2 through acidification and diffusion through a semi-permeable membrane is a very convenient strategy to enhance the selectivity and avoid poisoning of the electrode.

During this reaction generally forms free radical. thus two peaks are seen in mass spectrometer.

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