Can I test for Halides/Halogens cheaply and determine the concentration?

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In summary, inexpensive methods for testing for Halides/Halogens and determining concentrations include mass spectrometry and NMR. For quantitative analysis, gravimetric and electrochemical methods can be used. For ethylene dichloride, standard organic chemical methods or advanced instrumentation may be necessary.
  • #1
wxrocks
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Is there an inexpensive way to test for Halides/Halogens and put a rough quantity/concentration on the content?

Second, could Ethylene Dichloride cause a halogen test to come up positive? If so, what kind of amounts to produce 1ppm in a gallon of water would be needed?

Thanks!
 
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  • #2
wxrocks said:
Is there an inexpensive way to test for Halides/Halogens and put a rough quantity/concentration on the content?

Second, could Ethylene Dichloride cause a halogen test to come up positive? If so, what kind of amounts to produce 1ppm in a gallon of water would be needed?

Thanks!
you can test very easily for Cl and Br by using mass spec. (this depends if the mw of your compound is in the mass range for your instrument though). quantitative analysis would be harder. you would have to make standardized concentration curves probably, it is a pain. if ethylene dichloride is a contaminant in your product, it should show up on the NMR, which would also give you a handle on how much is in there as well. 1 L of water is 55.5 moles of H20. so if you had 1 ethylene dichloride molecule per 1million h20 (ok it is 1 in 999,999 but just use 1 million to make calculations easier, it won't be off by that much) molecules, you should be able to figure out easily how many molecules of ethylene dichloride are in 1 gallon of water with a concentration of 1ppm of ethylene dichloride.
 
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Let me see if I am getting my calculations right ---

If I scale up to a barrel -- about 208 L -- I should have about 11544 moles of H2O. Now, if I want to obtain a 25,000 ppm of eth. dichl., I would want a ratio of 25k molecules of eth dichl./974,000 molecules water. multiply that ratio back by 11544 and I get 296 moles of eth. dichl. I should need for my concentration.

The molar density of eth. dicl is about 99 g/mol. so 296*99 = 29304 g total eth dichl I need. With a denisty of 1.253 g/cm3, I get roughly 23 Liters of Eth. dichl. per barrel of water to get a concentration of 25,000.

Sound reasonable??
 
  • #4
wxrocks said:
Let me see if I am getting my calculations right ---

If I scale up to a barrel -- about 208 L -- I should have about 11544 moles of H2O. Now, if I want to obtain a 25,000 ppm of eth. dichl., I would want a ratio of 25k molecules of eth dichl./974,000 molecules water. multiply that ratio back by 11544 and I get 296 moles of eth. dichl. I should need for my concentration.

The molar density of eth. dicl is about 99 g/mol. so 296*99 = 29304 g total eth dichl I need. With a denisty of 1.253 g/cm3, I get roughly 23 Liters of Eth. dichl. per barrel of water to get a concentration of 25,000.

Sound reasonable??

looks good
 
  • #5
wxrocks said:
Is there an inexpensive way to test for Halides/Halogens and put a rough quantity/concentration on the content?

Second, could Ethylene Dichloride cause a halogen test to come up positive? If so, what kind of amounts to produce 1ppm in a gallon of water would be needed?

Thanks!

Quantitative analysis for some halides involve gravimetric analysis, for instance with Cl-, one can add AgNO3 to form AgCl (assuming that the solution isn't severely contaminated) and this precipitate can be dried, then weighed. The chloride content can be calculated indirectly through knowledge of the stoichiometric aspects of the experiment.

Another quick way to determine the chloride, or halogen content, is through electrochemical methods. Chloride, in particular, is a common agent in electrochemistry; e.g. AgCl reference electrode.

If you wanted to analyze ethelene dichloride, you would probably need to employ some standard organic chemical methods or use relatively more advanced chemical instrumentation/methods.
 

1. What is a halide/halogen?

A halide or halogen is a chemical element from group 17 of the periodic table. This group includes fluorine, chlorine, bromine, iodine, and astatine. These elements are highly reactive and often found in compounds with other elements.

2. Why is it important to test for halides/halogens?

Testing for halides/halogens is important because these elements are commonly found in various industrial and household products, as well as in the environment. They can have harmful effects on human health and the environment, and it is necessary to monitor their presence and levels to ensure safety.

3. How do you test for halides/halogens?

The most common method for testing halides/halogens is through a precipitation reaction using silver nitrate. This involves adding a silver nitrate solution to the sample and observing if a precipitate forms. The color and appearance of the precipitate can indicate the presence of specific halides/halogens.

4. What are the limitations of the test for halides/halogens?

The test for halides/halogens using silver nitrate is not specific, meaning other substances may also form precipitates and interfere with the results. Additionally, the test may not be sensitive enough to detect low levels of halides/halogens in a sample.

5. How can the results of a halides/halogens test be interpreted?

The results of a halides/halogens test can be interpreted by comparing the color and appearance of the precipitate formed to a known standard. The presence and concentration of specific halides/halogens can be determined based on the type and amount of precipitate formed.

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