Asking about extraction...

[brightsun]

Hi everybody, i have one question about extraction...

I'm running PAHs, i use EPA Method 8270d to analyze them. I use DCM:Acetone (1:1) to extract PAHs from the sample. But sometimes, they create colors with this sample (such as pink...). I don't know whether they react together to create this color ???

Thanks !

[Kwet]

I don't think that PAH's react together. PAH's colors ranged from yellow, amber to brown. Other colors should came from impurities in your sample. I remember to analyse some samples with pink extracts coming from waste sludges of a food industry.

[brightsun]

I mean whether there are reaction between solvents with extracts ???
You are right, i'm extracting from waste sludges of a food industry.
What happened in this situation ???

[tom jupille]

You probably have a lot of other compounds with fused aromatic rings. In general, the greater the number of conjugated double bonds, the lower the energy jumps (i.e., the longer the wavelength of light absorbed). At some point, the absorbance maximum creeps out into the visible, and you;re left with a pink color (the blue light is absorbed). Remember that your extraction is taking out *all* of the non-polars, not just the pnah's .

[AICMM]

brightsun,

Food sludges? I would guess there are dye's being used to give the food a certain color?

Best regards.