2. Discussion on Interferences and Filtration

When you extract water as it is raw water, sometimes you will get everything, all the interferences in your sample... These are interferences. So I must do something with these 2 before I go on the analysis of PAHs.

In the analysis of water samples, especially those from wastewater or sewage treatment, it is crucial to recognize that other materials present in the sample can interfere with the target analytes. For example, if we are analyzing for polycyclic aromatic hydrocarbons (PAHs), the presence of oils or metals in the water could skew our results. Thus, we need to identify these substances and address them to ensure accurate measurements.

Think of it like trying to taste soup when there are too many spices in it. If you’re trying to identify the flavor of basil but there’s too much garlic, it will be hard to pinpoint the basil flavor. Similarly, interferences in water samples can overshadow the analytes we want to measure.

So, before this you have to do liquid-liquid extraction, if you don’t want that information, you have to filter the samples... Normal sequence of events that you will see is the sample is collected then we move on, after this we do the next step.

Filtration is a necessary step before conducting liquid-liquid extraction as it helps remove larger particles that could interfere with the analysis. By filtering the sample first, we ensure that only the dissolved substances remain, allowing for more accurate assessments of what we wish to analyze in the water sample.

Imagine you are preparing to bake a cake. If you have flour mixed with big lumps, you wouldn't want to include those lumps in your mix. So, you sift the flour first to get a smooth mixture. Similarly, filtering the water samples gives a clear solution to analyze.

When you say total suspended solids it is we are taking a water sample and filtering it through a filter paper... mass of filter that is collected here divided by the volume of water will give you total suspended solids.

Total suspended solids (TSS) refer to the amount of particulate matter present in the water that can be captured on a filter. After filtering a water sample, the mass of the solids collected on the filter paper is divided by the volume of water filtered to determine the concentration of TSS. This measurement is important in assessing water quality, particularly for environmental monitoring.

Think of TSS like the residue left in a coffee filter after brewing coffee. The grounds that remain after filtering represent the solid particles (suspended solids) that can affect the clarity and quality of your drink (or in this case, the water body).

There is one piece of information that is needed here is, what is the filter paper that we use?... So, it will say 10 microns or it will say 1 micron you can go up to 0.4 microns.

The choice of filter paper is crucial because different filters have varying pore sizes that determine what can pass through them. Using too fine a filter can lead to longer filtration times and potential clogging, while too coarse a filter may allow unwanted particles to pass through. The right balance is key for effective filtration.

Selecting the proper filter is akin to choosing the right strainer for cooking pasta. If your strainer has too large holes, you'll end up with pasta in your sink. If it’s too small, water won't strain easily. Thus, a balance between size and functionality is necessary.

If I take a filter say I use 1 micron glass fiber filters... 0.7 is not really needed and 1 micron is probably good enough to do whatever collide removal you want.

Using different pore sizes of filters can significantly affect the efficiency of filtration and the purity of results. While a more precise filter may seem beneficial, it can slow down the process and provide negligible benefits in terms of the additional small particles removed. Thus, a 1 micron filter is often deemed sufficient for most analysis purposes.

If you think of filtering while making homemade lemonade, using a fine cheesecloth to strain out pulp may seem like a good idea, but it takes so long to pour. Using a coarser strainer can speed up the process without sacrificing much taste or quality.

So, 1 micron is set as standard filter size for TSS because it is TSS standard filter size... but still there is this question one has to draw a line somewhere.

1 micron filters are generally accepted as the standard for measuring total suspended solids as they provide a reliable method for quantifying solid content in samples without introducing excessive filtration time or complexity. It’s a practical choice in balancing precision and efficiency when analyzing water quality.

Much like how standard measurements like a tablespoon or cup are used in cooking to ensure consistent results, using a 1 micron filter in TSS measuring ensures that everyone gets reliable results, making comparisons across samples easier.

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