Have you ever thought to yourself I wish there was one way to effectively extract all of our aqueous samples? For instance, there are several methods available to extract aqueous samples, such as extraction method 3510 liquid-liquid extraction (LLE), method 3520 continuous liquid-liquid extraction (CLLE), and method 3535 solid-phase extraction (SPE). Wouldn’t it be more convenient to use one extraction method within the lab for most if not all of your aqueous extractions?
Working in an environmental lab requires a lot of concentration, both mentally and for the samples that you are working with. When New England finally begins to thaw and local companies rush to get their samples completed, a bottleneck that is usually experienced is the drying and concentration of so many samples. This bottleneck is partly due to ensuring that samples are extracted within their holding times. There have been many times I have had to multitask while concentrating samples on the TurboVap® classic, leading to some extra work when that rare sample was overconcentrated. Many of my past coworkers brought up the challenge they faced with the extraction of water and soils. In my opinion, the bigger issue was drying and concentrating. My main complaint with these steps was it was never efficient enough and I always had to baby each step so that all of my hard work (shaking the sample) did not go to waste. What I strived for most in the lab was an efficient and streamlined workflow for this part of the process.
When preparing your extracts for analysis, it is important to know which instrument to use and why you should be using that specific one. Of course, we know that each EPA method dictates which analysis instrument must be used within each method, however, we will be determining why that option was chosen in the first place in this blog post! Continue reading How does your sample prep change for LC/MS vs GC/MS
Have you ever thought to yourself am I using the best solid phase extraction disk offering for my application? Or can our prep lab turn samples around more efficiently if we choose a different SPE disk platform such as a single-use disk holder instead of cleaning our reusable holders? Those are just a few questions I receive when working with sample prep solutions with customers when SPE disks are brought up in the conversion.
Anyone familiar with Extractable Petroleum Hydrocarbons (EPH) methods such as those developed by Massachusetts DEP, New Jersey DEP, or one of the other various state agencies that regulate EPHs is familiar with the long and grueling process of fractionation. These methods require you to split the initial sample extract into two distinct fractions, the aromatic and aliphatic portions, which allow you to better characterize hydrocarbons that may be affecting the environment (for more info read out previous blog post). It is most commonly achieved through a manual method which is driven by only gravity that can cause quite a bottleneck in the lab. This process can be particularly finicky requiring you to determine the exact volumes needed so that you do not elute one fraction’s compounds into the wrong fraction by mistake. On top of this, the traditional procedure involves the use of gravity to elute the fractions through a cartridge which requires a lot of hands-on time to ensure that the cartridge does not go dry and that it is moved at the correct time. All in all, this process can cause many a headache when it does not run smoothly.
IR technology is a rapid and convenient tool for both qualitative and quantitative analysis that has been around for over a century. Traditional IR spectroscopy relies on vibration energies from the molecular bindings, where IR emission is absorbed by the bond when it has the same frequency as the specific vibration or movement as the bond.
Anyone familiar with EPH methods such as those developed by the Massachusetts or New Jersey Department of Environmental Protection is familiar with the long and gruelling process of fractionation. For those unfamiliar, with EPH or Extractable Petroleum Hydrocarbons it is an extraction that essentially occurs in two distinct parts: the initial extraction & concentration and then the fractionation of that initial extract into the aromatic and aliphatic fractions followed by concentration again. EPH is a method that replaces the TPH (Total Petroleum Hydrocarbons) or 8015 methods and allows for the calculation of specified carbon ranges giving you a more accurate assessment of potential health risks.
Do you ever tire of using sodium sulfate to dry your extracts? I know I do. That is why, whenever I get the chance to avoid using it, I do. The worst experience when using sodium sulfate is when you do not use enough of it, and the sodium sulfate reaches its maximum capacity leading to water breakthrough into your ‘what was supposed to be a dried extract.’ Then, you must dry the extract again with more sodium sulfate. When you are a high throughput lab, redoing steps is not ideal. Unfortunately, EPA Methods 525.2 and 525.3 require sodium sulfate drying as the drying technique, to name a couple, but not all EPA methods require sodium sulfate for drying. That is why when there is an alternative technique available and you are permitted to use it, why not use it?!
Believe it or not, we’re all familiar with emulsions. Have you ever added food oil to a pot of water while cooking? That’s an emulsion. Do you put dressing on your salad? It should be called salad emulsion – although, that may not have the same edible appeal. Do you drink milk? Emulsion. What about milk? Butter? Eggs? All emulsions.
If we’re referring to emulsions in the laboratory, the examples are different, but the chemistry involved is very similar – as are the mechanisms for breaking them. Continue reading Tackling Emulsions Just Got Easier