Flame tests: Are platinum loops worth the investment?

Sadly, the nichrome wires contaminate the colour of the flame, making it particularly difficult to see the lilac of the potassium, pale green of the barium or differentiating yellow from orange etc. Obviously this is not something we would give to KS3/KS4 and only be used for A-level core practicals (Edexcel has two). Each loop costs around £35 so it's quite an investment.

Anyone use platinum loops? Feedback please?

Cheers
 
Sadly, the nichrome wires contaminate the colour of the flame, making it particularly difficult to see the lilac of the potassium, pale green of the barium or differentiating yellow from orange etc. Obviously this is not something we would give to KS3/KS4 and only be used for A-level core practicals (Edexcel has two). Each loop costs around £35 so it's quite an investment.

Anyone use platinum loops? Feedback please?

Cheers
I think our Chemistry tech uses Nichrome or Constantan but heats them in a flame for quite a while to reduce the Sodium lines.
 
Yes, we wash thoroughly with conc. acid and heat them until they beg for mercy. When the nichrome eventually decides to resist even this treatment, we just swap out one piece of wire for another. They can take some battering over a few years before a truly permanent colour forms, albeit certain teachers have learnt magic ways to ruin a wire in a single lesson... putting a fresh wire on means no contamination whatsoever and some beautiful colours.
 

karen b

COMMITTEE
We invested in a set and they are labelled with whatever chemical they are for testing. We put it out like a circus so we don’t get cross contamination
 
Ever tried the CLEAPSS method using soaked wooden splints - works ok GCSE
Microsoft Word - PP038_Flame tests_splints_vMay2019.docx (cleapss.org.uk)

Preaching to the choir ;) . love the splint method which is what we tend to do for KS3/4, but for the core A-level practicals it's easier for us to provide loops given the way the practical runs. If they are easier to clean, last longer, give better colour (should in theory?).

Might just invest in one and try it out...
 

Peter Sigsworth

COMMITTEE
Preaching to the choir ;) . love the splint method which is what we tend to do for KS3/4, but for the core A-level practicals it's easier for us to provide loops given the way the practical runs. If they are easier to clean, last longer, give better colour (should in theory?).

Might just invest in one and try it out...
Thought that - just checking (cleapss say Y7 for splints anyway)
 
Sadly, the nichrome wires contaminate the colour of the flame, making it particularly difficult to see the lilac of the potassium, pale green of the barium or differentiating yellow from orange etc. Obviously this is not something we would give to KS3/KS4 and only be used for A-level core practicals (Edexcel has two). Each loop costs around £35 so it's quite an investment.

Anyone use platinum loops? Feedback please?

Cheers
Try the soaked wooden splints (Cleapss), they work and are very cheap.
 
Hey all, just received and tested my platinum wire.

I noticed a few things:

1) As expected, there is no colour at all imparted from the platinum, unlike the nichrome where you get a pale yellow/orange colour making it difficult to tell Ba and K flames in particular.

2) Platinum is a lot easier to clean than nichrome. I just need to dip it once (max twice) in HCl and it removes all traces of previous colours very quickly in the flame. I assume it's because the Pt surface is more inert and therefore less "sticky" to impurities?

3) Much cleaner colours which appear instantly.

Potential downside:

This could be me mishandling the wire, but as I was fiddling with the loop bit during cleaning, it snapped off. It sort of became brittle(?) probably due to how thin it is. Again, not sure if it was me or not, but something to be aware of.
 
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Nichrome and Constantan aren't very pure, so will have Sodium in the alloy. Platinum is very refined so will have very little flame colour.
 
We had this trouble and the teacher wouldn't listen to me when I told them not to use a roaring flame! use a colourless flames and don't hold it in too long the contamination should be less.

I also prefer the splint method one teacher "discovered" it so I am hoping it catches on
 
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