Brown marquis reagent ?

[BlackHaze]

I just bought a kit and my reagent looks brownish. Is it supposed to be this color?


http://imgur.com/W58srGY
http://imgur.com/2cdf7h2
http://imgur.com/W1uT0r8

 

[Madrus]

What are the odds! I just got a brown marquis from the same vendor.



From my experience, a brown marquis will still react with things that produce strong obvious reactions, like MDMA, but the initial brown color can be hard to detect other reactions. And overall the reactions seem to be slower.

Sulfuric acid + formaldehyde, why does it slowly turn brown?

 

[Transform]

The formaldehyde in the marquis reagent slowly polymerises over time, leading to discolouration. It's pretty fast and will only take a month or two at room temperature to show a colour like yours. As Madrus says, it doesn't generally affect the reaction but it can make subtle reactions hard to see.

Plastic bottles tend to accelerate this process, probably due to a combination of oxygen permeability and catalysis or reaction by/with the plastic itself. Glass bottles are harder to drip from but if you're not planning to use the reagent in 6 months then it's probably more sensible to go for a supplier using glass bottles.

Because of this the marquis reagent has one of the shortest shelf lives of the reagents - the froehde reagent lasts about 5x longer if you keep humidity out.