The Benefits of Glass Well Plate Inserts

96-well plates are commonly used consumables in high-throughput analytical labs that rely on mass spectrometry. Typically, polypropylene 96 deep well plates, available in 2mL square or 1mL round configurations, are the go-to choice. However, there are situations where polypropylene may not be suitable for contact with certain samples or extraction solvents. Additionally, when customers aim to automate their extraction process using a 96-well plate format but are concerned about evaporation, we recommend using 96 well plates with glass inserts to address these challenges.

Using Glass Inserts for Better Precision and Lower CV Values

One downside to using standard 96-well plates is that they are typically made of polypropylene. This can be problematic for assays with hydrophobic peptides, as they tend to stick to the plastic well plates.

To improve assay robustness, scientists can utilize our glass inserts in a 96-well plate format for the convenience of a 96-well plate with the compatibility and benefits of a glass vial.

A scientist presented his findings in a poster at a past MSACL conference. In summary: insulin detemir concentration, with its C14 myristic acid fatty chain, would decrease over time following elution from the antibody tips. This was due to the hydrophobic peptides sticking to plastic collection plates. By changing from plastic collection plates to glass inserts the precision decreased at least five fold for detemir and all other analogs, into an acceptable range of <10% CV. (Girtman, et al.)

Using Glass Inserts for the Analysis of Fatty Acid Methyl Esters (FAMEs)

Another benefit of utilizing the inserts in a well-plate format is the ability to seal the inserts with a molded PTFE/Silicone liner to reduce evaporation.

ABSTRACT: Fatty acids (FAs) are essential for building complex lipids, posttranslational modifications, and energetics. FAs can be imported from extracellular sources or synthesized by cells. The analysis of fatty acid methyl esters (FAMEs) by gas chromatography–mass spectrometry (GC–MS) allows for the quantitative analysis of long-chain and very-long-chain fatty acid content of cells. When coupled with isotopic labeling, this approach can elucidate the synthetic pathways being engaged by the cells, and the relative contribution of synthesis and import to maintain lipid content. Here, we describe a method for total cellular fatty acid analysis in macrophages. (Williams, et al.)

Williams et al. describe the use of glass inserts in an aluminum 96-well block, which allows a molded PTFE-lined silicone mat to be pressed into the inserts. An aluminum cover plate (with 96 holes) is then secured over the mat with screws. The additional aluminum cover puts consistent downward pressure on the PTFE-lined silicone mat and minimizes the chance of evaporation during extraction. Using glass inserts in a 96-well plate format for this type of assay allows for automation and improves the analysis.

Ease of Use

You'll notice that the glass inserts are packaged with 96 pieces in a plate loader. This makes transfering the inserts to the multi-tier system very easy. Simply put the base plate on top of the vial loader, invert and you'll have 96 inserts loaded into the plate format.

Conclusion

If you are looking to automate your analytical assay and use 96 well plates and are concerned with your sample coming in contact with plastic or evaporation, please reach out to Chrom Tech to discuss 96 well plate glass insert options.

References:

Girtman, Adam, Grebe, Stefan, Singh, Ravinder. “The Challenges Associated with the Development of a Clinically Viable Quantitative Insulin Analog Assay.” MSACL 2019 US : Girtman, www.msacl.org/view_abstract/MSACL_2019_US.php?id=928.

Williams K.J., Bensinger S.J. (2020) “Cellular Fatty Acid Analysis in Macrophage Using Stable Isotope Labeling.” In: Mishra S. (eds) Immunometabolism. Methods in Molecular Biology, vol 2184. Humana, New York, NY. https://doi.org/10.1007/978-1-0716-0802-9_4