New Podcast: Improving Results in Analytical Sample Prep

Analytical sample preparation has a huge impact on how clean your data is, and how long your column lasts. Pall’s new podcast series aims to simplify the sometimes-tricky task of choosing the most effective filtration device for your analytical samples. 

We get it. Sample preparation can be complicated. There is a delicate balance between removing contaminants without removing potentially important analytes present at low concentration. Moreover, how do you know which filtration membrane will work best with your sample and solvents? Or which pore size is optimal? How do you best protect your expensive column and analysis instrumentation?

Because few researchers have the luxury of spare time and resources to spend on investigating the myriad of filtration products available, Pall and LCGC are collaborating on a podcast that keeps scientists informed about the most important considerations for analytical sample preparation, and how to pick and choose the optimal filtration devices for their research goals.

Why is sample filtration so important?

The purpose of filtration in sample preparation is to remove particulate matter that can either harm analytical instrumentation or adversely affect analysis results. Anyone who has done HPLC or LCMS analysis understands the frustration of a blocked column or persistent contaminant signal. Optimized sample filtration saves time by decreasing column and instrument maintenance downtime.^[1] It saves resources by extending the life of an analytical column and reducing system wear and tear. Perhaps most importantly, sample filtration results in a better signal-to-noise ratio for analytical data. Clear, consistent signal resolution and good peak shape simplify data analysis and can reduce the number of times a sample will need to be run to get clear results.

Factors to consider when choosing a filter

The type of filter needed depends on the type of analysis being done. Whether the analysis will be high or low throughput, what the expected sample volume is, and what type of solvent is being used will all factor into the equation. The researcher also needs to consider which filter membrane material will best serve their purpose, and which pore size will best protect the analysis column and instrumentation, while still allowing for proper resolution of important analytes.

Once experimental conditions are clear, the researcher will still need to choose from available filter devices that suit their purpose. 

Syringe filters are a popular option when a relatively small number of samples are involved. Pall Analytical QC Acrodisc® syringe filters offer a full range of volumes, membrane types, and flow rates. They are available in 4mm, 13mm, and 25mm diameter sizes. Acrodisc syringe filters are designed to have excellent membrane compatibility, with low extractables and low protein binding.

For high throughput, low volume samples, filter plates are a great option. Multi-well filter plates can be used in combination with a vacuum manifold or automated handling platform and are available in a range of membrane materials and sample volume formats.

The impact of filter quality

It goes without saying that the quality of materials used during sample analysis impacts the downstream results. It is important to choose a filter device with a low extractable rating, to avoid chemical contamination of your sample. Extractables can leach from the filtration device itself, or from the housing or even packaging material, risking column clogging or interfering with data analysis. 

Aside from extractables, factors such as protein binding capacity and consistent product performance should be considered.

HPLC mobile phase filtration

Analytical filtration is not limited to the samples themselves. Ideally, HPLC mobile phase solutions should also be filtered be ensure that they are free from any particulate contamination.^[1] While people often overlook mobile phase solutions, especially those marketed as HPLC grade, no solvent is guaranteed to be 100% free of contaminants. Solvent mixtures made up in the lab are particularly vulnerable to inadvertent contamination from glassware and from solution containers designed to be opened multiple times.