Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: FireflySci on August 11, 2015, 04:41:23 PM
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Hello everyone. I recently planted a vegetable garden in our backyard. It's amazing seeing how plants grow and seeing how the veggies change color as they ripen. Anyway, The spot I used has grass that was treated with lime and who knows what other chemicals. Now I don't want to eat the vegetables in case they have something that is not safe.
I know you can test the soil using a spectrometer, but can you test the soil and/or produce with a spectrophotometer? Our lab does not have a spectrometer.
I've been trying to find a local lab who has a spectrometer but no one has gotten back to me.
Basically I want to know if the food is safe to eat. I would like to test for heavy metals and any other harmful chemicals.
Any ideas on how I can do this?
Thank you for the *delete me*
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You can test anything with anything - but you need to know what you are looking for. Spectrophotometers come in all shapes and sizes - what do you hope to find with this tool? It is generally not a good general tool for finding low concentrations of specific substances in complex matrices.
If you want to look for heavy metals (which ones?), ICP-MS would be the method of choice. But sample preparation is necessary (you can't nebulize a red pepper), so you'll need at the least a good hot plate, some concentration high grade acid, and a fume hood. Better would be an ashing oven and better than that would be a microwave digester. There are contract labs that will do this kind of thing.
Organic contaminants can also be analyzed, but here specifying what you want to find is even more important. Pesticides? Which ones? LC/MS or some variation is probably what you'd want to use, but broad "I want to find out if anything is in there" studies are pretty unrealistic.
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Hello everyone,
I apologize for reviving this old topic, but I find this discussion extremely relevant to my current situation. I'm a student, and as part of my coursework, I have to carry out an experiment on plant growth starting this spring to pass my end-of-year report. The aim is to produce home-made compost that I'll use as a natural fertilizer.
Although the exchanges here remain instructive, I'd like to have a few clarifications concerning :
- Deep-cleaning the barrel: Assuming that methanol is the only chemical present (which remains to be confirmed in my case), would multiple rinses with hot water be enough to make the container safe? Are there other effective and affordable cleaning methods to neutralize any residual traces?
- Absorption by plastic: Some members mentioned that plastic materials may have absorbed traces of chemicals. Is there a simple way to test if the plastic is still contaminated, or would natural evaporation suffice to eliminate these residues over time?
- Other possible contaminants: In the event of other unknown substances being present in the barrel (which I also fear), do you think this could pose an indirect risk to plants and, by extension, to the consumption of cultivated vegetables? How could this risk be minimized?
Your expertise would be a great help in ensuring that my approach is both safe and environmentally friendly. Thank you in advance for your advice!
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You ask your questions kinda out of nowhere, not explaining the setup nor the situation, so it is quite difficult to comment on.
Deep-cleaning the barrel: Assuming that methanol is the only chemical present (which remains to be confirmed in my case), would multiple rinses with hot water be enough to make the container safe? Are there other effective and affordable cleaning methods to neutralize any residual traces?
If it is just methanol that is important I would just leave the barrel open for several weeks, should be enough.
Absorption by plastic: Some members mentioned that plastic materials may have absorbed traces of chemicals. Is there a simple way to test if the plastic is still contaminated
No.
or would natural evaporation suffice to eliminate these residues over time?
Depends on what they are. Not everything is volatile.
Other possible contaminants: In the event of other unknown substances being present in the barrel (which I also fear), do you think this could pose an indirect risk to plants and, by extension, to the consumption of cultivated vegetables?
No way to even speculate not knowing history of the barrel. In general: yes. In practice: highly unlikely.
How could this risk be minimized?
Washing that you suggested for methanol will definitely help.