A new method has been developed for the combined analysis of Vitamin A, Vitamin D, Vitamin E and Vitamin K from serum using LC-MS/MS. The method uses supported liquid extraction (SLE) with a novel sample load which could also potentially be employed for many other highly non-polar analytes that have limited water solubility and are highly protein bound within the body.

Urine samples are composed of many interferents which can cause ion-suppression or ion-enhancement when analyzing by mass spec. Build up of these matrix components over multiple sample injections can lead to loss of signal in the mass spec and even unexpected changes in your chromatographic separation. We are going to discuss why not performing adequate sample prep can be detrimental for your analyses.

When would I choose SLE? When would I choose SPE? We all have faced those questions. Let's have a look at the two sample preparation techniques. 

Synthetic cannabinoids are some of the most widely abused drugs in the world. They are structurally similar and have similar effects to marijuana but are frequently referred to as “legal highs”. Chemists are constantly changing the structures of these compounds to keep them in a legal state and governments can’t keep up with adding them to scheduled lists. So, how do we analyze for these compounds? How can they be easily extracted from whole blood?

Have you ever encountered problems loading your samples onto an SPE or SLE plate?  Aside from sample viscosity or cartridge blockages, a good troubleshooting step to start with is ensuring that you are achieving complete frit coverage on the load.

Often the question arises asking how can I extract both acids and bases with the same Supported Liquid Extraction (SLE) procedure. Is this possible? And how?

It happens to all of us. We're getting a new method developed and validated and then it comes time to run our negative urines. And everything comes up as positive! There are peaks for our analytes of interest in every urine that we run! How is that possible?

If you are frustrated with low recoveries caused by protein binding during Supported Liquid Extraction (SLE) and Solid Phase Extraction (SPE), this blog post will give you a few tips. Proper sample pre-treatment is the key to solving this issue.

When it comes to sample cleanup the question occasionally comes up asking what technique is best for my application: Solid Phase Extraction (SPE) or Supported Liquid Extraction (SLE)? Well, what’s right for you depends on your application and the characteristics of your analytes. This post outlines some of the advantages, disadvantages and limitations of each technique.

For many of us developing an analytical assay requires numerous experiments in addition to lots of data review, and yet despite the feeling of confidence in our success, how reliable is our assay really? How do we measure reliability of our assay?