4. Organic and Elemental Carbon Analysis

So we want to do the composition of PM, you have 2 options again you can look at organic or inorganic. So we are looking at organic you know the instruments that are used for organic we saw that already in terms of the water, if you want to look at organic chemicals, there are a set of instrumentation that you can use starting from the GC or LC or any of those instrumentation.

In this chunk, we introduce the two main categories of carbon analysis: organic and inorganic. The focus is on organic analysis, wherein various instruments such as Gas Chromatography (GC) or Liquid Chromatography (LC) are employed to study organic compounds. Organic carbon analysis is essential because it helps identify different carbon compounds present in particulate matter (PM) and their sources.

Think of organic carbon analysis like examining a soup's ingredients. Just as you identify each ingredient (like vegetables, meat, or spices) to understand the soup better, organic analysis allows scientists to identify different organic compounds to understand their presence in air particulate matter.

So, let us say a particle is there, this particle itself may be an organic particle, which means that you have to dissolve the entire particle into a solvent. So, that is one option. Second option is if the organic material is adsorbed on other particles and when you have to pull these particles out, you have to dissolve or desorb.

This chunk discusses the two primary methods for analyzing organic particles in particulate matter (PM). One approach is to dissolve the entire particle in a suitable solvent to extract its components. The second method involves desorbing organic materials that are attached to other particles. This distinction is crucial since the chemical nature of the particles can significantly affect the analysis.

Imagine trying to retrieve a chocolate chip from a cookie. You could either dissolve the entire cookie in hot milk (dissolution) to get the chocolate or gently scrape it off with a knife (desorption). In our analysis, we must choose the appropriate method based on how the organic materials are associated with the particles.

Here again there is a distinction. So, if you want to pull out look at composition of some of these things, if they are adsorbed on something else, they will nicely show up in something like the GC or LC but if it is pure carbon, it may not show up there because it will not dissolve in anything, it will sit there and it is elemental.

In this segment, we differentiate between organic carbon and elemental carbon. Organic carbon includes compounds comprised of carbon along with other elements such as hydrogen and oxygen, while elemental carbon refers strictly to carbon in its pure form. This distinction is important because while organic carbon can often be analyzed using standard methods, elemental carbon may need alternative techniques since it does not dissolve in solvents like organic carbon does.

Consider a fruit salad (organic carbon) versus sugar (elemental carbon). While you can easily identify and taste each fruit in the salad using a fork, trying to analyze sugar might require a different method, like dissolving it in water to understand its properties, which is not needed for the fruit salad.

The other kind of analysis that you have is inorganic analysis. So, inorganic analysis, you can do 2 kind of things you can do elemental analysis or you can do ions, you can get what is present on the particle by either of these methods.

This chunk introduces inorganic analysis, which can either focus on elemental analysis (e.g., identifying specific metal concentrations) or ion analysis (e.g., detecting specific ions in the particulate matter). Both methods provide valuable information about the composition of particles in the air and can inform pollution sources and impacts.

Think of inorganic analysis as checking the nutritional content of a food item. Elemental analysis is like checking how much protein or fat is there, while ion analysis is akin to inspecting for specific vitamins or minerals. Each type of analysis sheds light on different aspects of the nutrients in the food.

What solvent can we use and how? An acid, which is the acid that has capacity to dissolve everything, HNO3, so all nitrates are supposed to be soluble.

This section explores the extraction process for metals in particulate matter analysis. Concentrated nitric acid (HNO3) is often used as a solvent because it effectively dissolves various metals from PM. However, special care must be taken since extracting requires considering the material of the filter used to collect the samples and potential interferences that might arise during the analysis.

Imagine cleaning an old metal pot with vinegar (acid) to remove rust. Just like vinegar helps dissolve the rust, nitric acid helps dissolve certain metals in particulate samples. However, you must be careful not to use the wrong cleaning materials that could scratch or damage the pot.

So, you have at least 3 filters. One for each and they are running concurrently, which means that you need to have 3 EPM sampler or 3 of these sampler running concurrently.

This chunk discusses the practical needs for collecting air samples for analysis. It highlights that at least three different filters are necessary to separately capture organic carbon, elemental carbon, and metal content. The need for concurrent sampling ensures accurate data collection across different analyses, allowing for comprehensive profiling of the particulate matter.

Think of this as preparing a party where you need to set up three different tables for appetizers, main courses, and desserts. Each table serves a different purpose, ensuring your guests get a complete dining experience. Similarly, using separate filters ensures that each type of carbon or metal is accurately captured for analysis.

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