Sodium Sulfite = E221?

[AlexRT]

Could somebody explain: Sodium Sulfite and E221 is it same?

E221 is a food additive and used as a synthetic food preservative to prevent discolouration in dried fruits.
The common name for E221 is sodium sulphite. I bought this element in the online food shop.

Sodium Sulfite is cost in three time more when you buy it in the Chemical Shop. I would like to ask - why? is it difference or same, and if I buy Sodium Sulfite in the food store - would I use it in a developer formula or not?

Both of them have the same chemical formula: Na2SO3


Thanks in advance

 

[Ian Grant]

Yes it's the same, E numbers are allocated by the EU to permitted food additives.

Sodium Sulphite is E221
Sodium Bisulphite is E222
Sodium Metabisulphite is E223
Potassium Metabisulphite is E224.

Ian

 

[Anon Ymous]

The price mismatch could be attributed to different grades of this chemical. Analytical reagent grade will be more expensive, sometimes far more expensive. IMHO, having a cheap source for sodium sulfite is a prerequisite for scratch mixing your chemicals, otherwise it gets too expensive.

 

[AlexRT]

ok, thanks for so detail answers - it is clear now for me

 

[Gerald C Koch]

If it's safe to add to food it probably safe to use with photographic products. There is a designated photo grade but this only guarantees that the chemical will not cause problems when used with film and papers. Often photo grade is less pure than the other grades.

If you are interested in ascorbic acid developers then look for erythorbic acid also used as a food additive. It is an isomer of ascorbic acid and actually works a bit better as a developing agent.

 

[grommi]

You can also use "bubble-ex" (or similar) for water beds, just be sure that it is pure sulfite. Mine was dirt cheap and works, no probs at all.

 

[pdeeh]

erythorbic acid ... is an isomer of ascorbic acid and actually works a bit better as a developing agent.

In what way better?

 

[zanxion72]

Also, there is the Sodium Sulfite Anhydrous that is more expensive than the food grade S.S. and more resistant to oxidation by air. Most developer recipies call for this. Food grade S.S. is usually the S.S. decahydrade or crystal.
In a formula that needs Anhydrous, double the quantity of the Decahydrate.

 

[Gerald C Koch]

In what way better?

It is a bit more active.

 

[dE fENDER]

It is a bit more active.

Did pure D-isomers have any photographic activity at all?

 

[Gerald C Koch]

Did pure D-isomers have any photographic activity at all?

If you look at the structure given in the article below you will see that erythobic acid obeys the Kendall-Peltz rule. The stereo isomer differs only in a side group and therefore has no effect. If you look at some ads for erythoric acid you will see photographic develops as one of the uses listed.

https://en.wikipedia.org/wiki/Erythorbic_acid