Breakdown products of phenanthrene in sediment samples.

[xujing]

I'm trying to identify the breakdown products of phenanthrene in sediment samples.

I applied remediation method to phenanthrene spiked sediment. After the treatment, I hope to find breakdown products in the sediment samples and overlaying water samples. However, I don't know how to extract the samples.

I guess the breakdown products might indlude quinone, hydroquinone and fatty acids.

Can anyone please give me some suggestion how I can find out what the breakdown products are?

Thank you very much!

[xujing]

can anyone help me with this problem please?

[wsayers]

Your compound of interest (phenanthrene) is listed as one of the analytes for US EPA method 8270. (method for semivolatile compounds)
Typical instrumentation for this method is a benchtop GCMS quadrupole

US EPA method 3545 is appropriate for extracting your soil or other solid samples. A soxhlet extractor is used to transfer the analytes into a suitible solvent, such as dichloromethane.

The water portion of you samples can be prepared by liquid/liquid extraction into dichloromethane using a common seperatory funnel.

Water samples need to be extracted three times. (low-mid and high pH)
to ensure that all compounds are extracted. The three dichloromethane extracts can be recombined into a single sample prior to a blow-down to concentrate the sample. ( 500ml of extract may be evaporated down to 1ml to get a 500:1 preconcentration, for example) The combined extract is sometimes reffered to as bna (base/nuetral acid) extractables.

Solid phase microextraction and or a headspace sampler are more modern ways of dealing with the same problem, but require additional equipment.

Best of Luck

[xujing]

Hi, Wsayers,

Thanks!

I'm extracting my sediment and water samples by the ways you mentioned. However, I want to know if there is any other compounds in my samples, such as fatty acids, quinones, phenols, etc. I want to know if it is OK to extract it as the ways you mentioned to find out whether there is any compound I'm interested in or not .

[Rick Jagielski]

You can expect pretty much anything that will dissolve in MeCl2 to be extracted.

Rick

[wsayers]

Rick is correct, the full extraction sequence should pull everything over.

One possible area to look into,, although I would not expect large anounts of fatty acids from phenanthrene degradation, if they are formed, acids tend to have peaks with considerable tailing, and or poor sensitivity levels.
Acid peaks usually look like "shark fins on a 5-phase or 1-phase column.

Fatty acids are generally analyzed as methyl esters. You should be able to get commercial standards to confirm identity. The esterification treatment will sharpen the peaks and make any acids much more GC friendly. Derivitization will add ~ 1/2 hour of prep time, don't do this unless you really need to.

Good luck with your project.