Analytical Chemistry and Chromatography Techniques
The Do’s and Don’ts of HPTLC
This followup article on HPTLC gives a list of dos and don’ts while performing HPTLC to achieve precise and error-free results, and avoid false positives.
Read More HPTLC: Basics and Instrumentation
Get robotic with HPTLC! This automated version of TLC can separate and quantify compounds – find out how!
Read More Should You Switch from Wet to Dried Blood Samples?
A Spot of History Most of the biomedical methods used started as a curiosity. Then the one-off gains a limited use, the technology then progresses until its use becomes widespread. Just think about the arch from the curious polished glass spheres, used by Antony Levnhook to look at animalcules, to modern microscopes. The same story…
Read More Crash Course in Fourier Transform Infrared Spectroscopy
Fourier transform infrared spectroscopy (FTIR) is an extremely sensitive technique for measuring the absorption and intensity of electromagnetic radiation in the infrared region of the spectrum of either a solid, liquid or gas sample. You can use FTIR to: quantify unknown compounds identify unknown compounds study the detailed structured coordination of compounds How Does Fourier…
Read More Applying Your MALDI Matrix Like a Boss
Matrix-assisted laser desorption/ionization (or simply, MALDI) is a type of mass spectrometry method. If you are new to mass spectrometry, check out our excellent primers, titled How Does Mass Spec Work and Get Out of Western Blot Hell: An intro to Mass Spec. Basically, however, mass spectrometry allows you to measure, sort, and quantify small…
Read More HPLC Tubings and a $200.000.000 NASA Crash: Converting Between Measurement Systems
In an amazing TED-Ed video from Matt Anticole, the wild history of the metric system is explained as a very smart cartoon. Matt concluded his video with a rather positive message for the scientific community: “Nevertheless, the metric system is almost universally used in science and medicine.” It sounds great, but the key word here is…
Read More Examining Cell Interactions with Surface Plasmon Resonance (SPR) and Identifying Epitopes using SPR-Mass Spectrometry (MS)
Surface plasmon resonance (SPR) offers highly efficient, label-free detection for quantifying biomolecular interactions in real-time. Two exciting SPR variants that have sprung up in recent years are SPR for cellular analysis and SPR-mass spectrometry (SPR-MS). SPR for cellular analysis allows you to study how cells attach to different substrates and each other, while SPR-mass spectrometry…
Read More All Charged Up: The Basics of Ion-Exchange Chromatography
Highly pure proteins are vital for successful experiments; they play roles in research as assay reagents (especially for SPR applications), therapeutic candidates, and of course, as the subjects of structural and biochemical studies. Chromatography is the science of separation and we utilize it to isolate and purify proteins based on their unique physiochemical properties. One…
Read More The Importance of Metabolomics Research
Metabolomics may sound like a fictional character in the famous comic series “Asterix”, but it is very important in understanding systems biology and in clinical research against various diseases. Metabolomics is the last piece of a puzzle of omics applications following genomics, transcriptomics, and proteomics. It allows us to ask “What has happened and what…
Read More Critical Factors for Full Characterization of Biosimilars
Today, about half of all therapeutic drug approvals by the US Food and Drug Administration (FDA) are for biological drugs. That number is expected to rise to 75 percent by 2025. When these biologics come off patent, the gates will open for a flood of biosimilar drugs (biopharmaceutical generics) that are designed to be much…
Read More Key Analytical Challenges for Antibody Drug Conjugates
Currently, there are more than 75 antibody drug conjugates (ADCs) in various stages of pre-clinical and clinical development. The combination of a targeted antibody coupled with a cytotoxic small-molecule drug (via a flexible linker) makes for a lethal and specific oncologic drug product. However, an ADC is a heterogeneous cocktail of molecules with a range…
Read More Pack a Chromatography Column Like a Pro
You already learned the basics of column packing. When moving to more automated system using low pressure liquid chromatography systems, you can use pre-packed columns. But in order to compare several resins in specific conditions, and also to save money, you might need to pack your own low pressure columns. The art of packing a column…
Read More To Run or to Fly: A Comparison Between HPLC and GC
Many chemical compounds, including drugs and metabolites, can be analyzed by either gas chromatography (GC) or high-performance liquid chromatography (HPLC). Because both techniques function under the same basic principles of compound separation, identification, and quantification, it can sometimes be tricky to choose one over the other. But knowing what differentiates HPLC and GC can definitely…
Read More Ten Ways to Give Your Surface Plasmon Resonance Experiments a Hand
Surface Plasmon Resonance (SPR) is the gold standard for measuring biomolecular binding without the need for labeling (i.e., label free detection of kinetics). SPR is especially valuable because it doesn’t just provide information at the start and end of a binding event, but can be used to follow association and dissociation kinetics of biomolecules in real-time.…
Read More How to Clean and Unclog Your HPLC Column
In my last article, I discussed how to best keep your lab’s HPLC running smoothly. However, even the best-maintained HPLCs and columns need periodic cleaning. Today, I’ll describe how to identify and troubleshoot a clogged HPLC column. Columns Are Finite First of all, it’s important to realize that columns do have a finite lifetime. The…
Read More How to Separate Nucleotides Using Ion-paired Reverse Phase HPLC
If you work in the field of molecular biology, there is hardly a day that goes by that you don’t use nucleotides. But beyond the use of the four well-known deoxynucleotides in PCR, you can use nucleotides for several other applications. For example, kinases and phosphatases use nucleotides as substrates, and phosphotransferases transfer phosphate group…
Read More Under Pressure: Tips for Keeping Your HPLC Up and Running Properly
If you’re anything like me, your biggest lab fear is working with expensive equipment prone to damage. HPLC is a wonderful tool, capable of separating, identifying, and quantifying a vast array of compounds, but it requires an attentive scientist to properly handle and maintain each component. In this article I’ll describe a few basic handling…
Read More Using a Gel Filtration Chromatogram to Estimate Molecular Weight
Gel filtration chromatography (also known as size exclusion chromatography, molecular sieve chromatography, or gel permeation chromatography) is based on the differential distribution of the components in a sample between the mobile and stationary phases. Specifically, in gel filtration chromatography, this differential distribution depends on the size and shape of the components. Here, we take a…
Read More FTIR Spectroscopy: Every Window Needs a Good Acid Wash
Fourier Transform Infrared spectroscopy (FTIR spectroscopy) is a useful and exquisitely sensitive technique used to identify and quantify unknown compounds, as well as study fine molecular details. However, to obtain a meaningful IR spectrum, it is not only important to prepare the sample correctly but also to learn how to clean the apparatus that houses…
Read More Gel Filtration Chromatography Media: What You Need to Know
Do you use pre-packed Superdex 75 or Superdex 200 columns for gel filtration chromatography? Ever wonder if other media could better address your purification needs? Look no further. Your quest ends here! But if you’re looking for information on gel filtration principles, check out this earlier article. Choosing a Column for your Gel Filtration Experiment…
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