Chromatography Forum

Hi, I have a request to analysis Carbon black. Not sure what analytical techqniue i could use. Clearly cannot use HPLC with UV or GC with ECD/FID

thank you

Dibba

Analyze it for.... pesticides? PCBs? Volatiles? Particle size? Or are you trying to identify carbon black in a matrix, like water or soil?

The technique involves dosing carbon paste (by volume/weight) to in-vitro donor dermal skin then analysing the substrate after adsorption. Therefore following matrix would be assessed for mass balance: cotton wool wash, tape-strips and the skin. Essentially, assessing for the amount of carbon present.

Dibba

I can't imagine doing it by chromatography. Non-dispersive IR maybe?

Typically "Carbon Black" is measured by thermal/gravimetric method. I posted a link to a quick summary of it: http://www.osha.gov/dts/sltc/methods/in ... id196.html

There are other methods that may work as well:

You could use a total carbon analyzer. They are usually able to differentiate between inorganic and organic carbon using either a UV/persulfate method or Thermal Catalytic Combustion. There are many vendors for these instruments. They typically require an aqueous sample but some sell a solids attachment for which your sample will have to be finely ground or pulverized. This is usually the instrument used that Tom was talking about that uses non-dispersive infrared detector (NDIR) to detect carbon as CO2 after it has been oxidized by one of the two above methods mentioned. I'm not sure if this method will give you the "Carbon Black" value you want though.

Shimadzu http://www.ssi.shimadzu.com/products/pr ... 000000ywzu, Tekmar,OI Analytical, Thermo all make them.

There is another method to measure organic carbon/elemental (black) carbon and total carbon using Thermal/Optical analysis. These were developed for air particulate analysis, however. There may be a way to analyze them on these instruments if your sample is ground or pulverized. I have seen papers where people were analyzing sediment and soil samples with them. I used one in grad school to measure OC/EC in bulk PM dust (rather than collect it on a quartz filter). Two companies sell them: Desert Research Institute and Sunset Labs. I have used the one from Sunset Lab Inc. http://www.sunlab.com/

The main problem with "Carbon Black" analysis is that the quantitative value is highly dependent upon the method of analysis. What is considered to be "carbon black" should theoretically be all inorganic and graphic-like carbon. However, each method has its drawbacks as there is no defined line between Organic and Black carbon in the "real-world." But most people asking for "Carbon Black" analysis are asking for the Gravimetric result which has been the standard for decades.