Talk:Dithionite: Difference between revisions
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However, purity is not important in this case, You just have to introduce enough of it to bring the oxygen to the desired level or an excess to make sure you have 0 oxygen. And you do not use this compound in an actual biological experiment with samples. | However, purity is not important in this case, You just have to introduce enough of it to bring the oxygen to the desired level or an excess to make sure you have 0 oxygen. And you do not use this compound in an actual biological experiment with samples. | ||
best greetings | best greetings | ||
Mario | --[[User:Fasching Mario|Fasching Mario]] 09:08, 18 January 2012 (CET) | ||
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'''Question:''' | '''Question:''' | ||
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It is true that with the ongoing switch to the GHS system(globalĀ Ā Ā harmonized system) dithionite was "upgraded" to status "selfĀ Ā Ā heating substance, category one". This category is mostly relevantĀ Ā Ā for shipping / storage of bulk quantities ( like several stackedĀ Ā Ā Ā 50 kg bags or a rail car). Even during the process of definingĀ Ā Ā criteria for the GHS implementation in Europe nobody seemed toĀ Ā Ā have a clear idea what to do with this new category. In a draftĀ Ā Ā paper I found the following quotation:Ā Ā Ā Ā "Since this hazard class of Self-heating substances and mixturesĀ Ā Ā appears not to match the level of concern as ādangerousā, we doĀ Ā Ā not consider that it is consistent with the general principlesĀ Ā Ā for our choice of building blocks to include this class in AnnexĀ Ā Ā I. The text for this class isĀ Ā Ā shown as strike-through".Ā Ā Ā Ā No new safety precautions were added so the already recommendedĀ Ā Ā safety measures (regarding the reactivity) are stillĀ Ā Ā P235+P410 : Keep cool. Protect from sunlight.Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā For the very small amounts I am not very much concerned. Even ifĀ Ā Ā dithionite does decompose (e.g. by reacting with water vapor) theĀ Ā Ā amount of heat that can be producedĀ by a small amount is quiteĀ Ā Ā minor. While the the vial we use for day to day use (and isĀ Ā Ā delivered with the oxygraph) is extremely small, I am aware thatĀ Ā Ā the substance is only available in slightly higher quantities fromĀ Ā Ā Sigma (50 g). This is still a very small quantity for peopleĀ Ā Ā discussing (and regulating) dangers of bulk storage but for the 50Ā Ā Ā g vessel you certainly should take the official precautionsĀ Ā Ā (P235+P410) seriously.Ā Ā Ā Ā Ā Ā Ā Non the less: Never depose this substance while "dry", e.g,Ā Ā Ā throwing the powder into a waste basket. It might react with theĀ Ā Ā dangerous water /paper combination. Store any amounts of theĀ Ā Ā powder in paper / cardboard. Never Store comparable large amountsĀ Ā Ā Ā (like the 50 g) near large amounts of paper / cardboard. TheseĀ Ā Ā points areĀ of course true for all chemicals (and therefore notĀ Ā Ā mentioned in safety guidelines), but for this particular substanceĀ Ā Ā they are particular important.Ā Ā Ā --[[User:Fasching Mario|Fasching Mario]] 12:12, 3 July 2012 (CEST) | It is true that with the ongoing switch to the GHS system(globalĀ Ā Ā harmonized system) dithionite was "upgraded" to status "selfĀ Ā Ā heating substance, category one". This category is mostly relevantĀ Ā Ā for shipping / storage of bulk quantities ( like several stackedĀ Ā Ā Ā 50 kg bags or a rail car). Even during the process of definingĀ Ā Ā criteria for the GHS implementation in Europe nobody seemed toĀ Ā Ā have a clear idea what to do with this new category. In a draftĀ Ā Ā paper I found the following quotation:Ā Ā Ā Ā "Since this hazard class of Self-heating substances and mixturesĀ Ā Ā appears not to match the level of concern as ādangerousā, we doĀ Ā Ā not consider that it is consistent with the general principlesĀ Ā Ā for our choice of building blocks to include this class in AnnexĀ Ā Ā I. The text for this class isĀ Ā Ā shown as strike-through".Ā Ā Ā Ā No new safety precautions were added so the already recommendedĀ Ā Ā safety measures (regarding the reactivity) are stillĀ Ā Ā P235+P410 : Keep cool. Protect from sunlight.Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā For the very small amounts I am not very much concerned. Even ifĀ Ā Ā dithionite does decompose (e.g. by reacting with water vapor) theĀ Ā Ā amount of heat that can be producedĀ by a small amount is quiteĀ Ā Ā minor. While the the vial we use for day to day use (and isĀ Ā Ā delivered with the oxygraph) is extremely small, I am aware thatĀ Ā Ā the substance is only available in slightly higher quantities fromĀ Ā Ā Sigma (50 g). This is still a very small quantity for peopleĀ Ā Ā discussing (and regulating) dangers of bulk storage but for the 50Ā Ā Ā g vessel you certainly should take the official precautionsĀ Ā Ā (P235+P410) seriously.Ā Ā Ā Ā Ā Ā Ā Non the less: Never depose this substance while "dry", e.g,Ā Ā Ā throwing the powder into a waste basket. It might react with theĀ Ā Ā dangerous water /paper combination. Store any amounts of theĀ Ā Ā powder in paper / cardboard. Never Store comparable large amountsĀ Ā Ā Ā (like the 50 g) near large amounts of paper / cardboard. TheseĀ Ā Ā points areĀ of course true for all chemicals (and therefore notĀ Ā Ā mentioned in safety guidelines), but for this particular substanceĀ Ā Ā they are particular important.Ā Ā Ā --[[User:Fasching Mario|Fasching Mario]] 12:12, 3 July 2012 (CEST) | ||
Revision as of 13:07, 3 July 2012
Question:
Hi Mr. Fasching, I could not find any detailed information about the % purity of Oroborosā Sodium Dithionite (#26600-21). Do you think that 85% purity is sufficient (for example, Sigma#157953)? Thank you very much.
Answer:
Yes thats what we use and that quality is the best you can get. Its an inherently unstable chemical, therefore the low purity. If it would be stable it would not be suitable for our purpose :-(. However, purity is not important in this case, You just have to introduce enough of it to bring the oxygen to the desired level or an excess to make sure you have 0 oxygen. And you do not use this compound in an actual biological experiment with samples. best greetings --Fasching Mario 09:08, 18 January 2012 (CET)
Question:
I am concerned about the safety of sodium dithionite.
It is true that with the ongoing switch to the GHS system(global harmonized system) dithionite was "upgraded" to status "self heating substance, category one". This category is mostly relevant for shipping / storage of bulk quantities ( like several stacked 50 kg bags or a rail car). Even during the process of defining criteria for the GHS implementation in Europe nobody seemed to have a clear idea what to do with this new category. In a draft paper I found the following quotation: "Since this hazard class of Self-heating substances and mixtures appears not to match the level of concern as ādangerousā, we do not consider that it is consistent with the general principles for our choice of building blocks to include this class in Annex I. The text for this class is shown as strike-through". No new safety precautions were added so the already recommended safety measures (regarding the reactivity) are still P235+P410 : Keep cool. Protect from sunlight. For the very small amounts I am not very much concerned. Even if dithionite does decompose (e.g. by reacting with water vapor) the amount of heat that can be produced by a small amount is quite minor. While the the vial we use for day to day use (and is delivered with the oxygraph) is extremely small, I am aware that the substance is only available in slightly higher quantities from Sigma (50 g). This is still a very small quantity for people discussing (and regulating) dangers of bulk storage but for the 50 g vessel you certainly should take the official precautions (P235+P410) seriously. Non the less: Never depose this substance while "dry", e.g, throwing the powder into a waste basket. It might react with the dangerous water /paper combination. Store any amounts of the powder in paper / cardboard. Never Store comparable large amounts (like the 50 g) near large amounts of paper / cardboard. These points are of course true for all chemicals (and therefore not mentioned in safety guidelines), but for this particular substance they are particular important. --Fasching Mario 12:12, 3 July 2012 (CEST)
