Evaluation of Water-Soluble DBS for Small Proteins: A Conceptual Study Using Insulin as A Model Analyte

Abstract

Aim: Water-soluble sampling materials for DBS have been introduced to solve some of the common challenges of DBS. Methodology: Carboxymethyl cellulose (CMC) as water-soluble material was evaluated for small proteins using insulin as model analyte. 15 µl of whole blood was deposited and dried on a sheet of CMC prior to dissolvation of the whole spot, matrix precipitation with acetonitrile and LC–MS/MS analysis. Results: CMC was shown to promote matrix precipitation resulting in cleaner extracts than precipitation without CMC present. The recovery of insulin from the spot was 68 ± 4%, and the spotted samples were stable for at least 1 week in room temperature. Conclusion: Water-soluble DBS showed promising performance also in analysis of small proteins.

Keywords::

• carboxymethyl cellulose
• DBS
• insulin
• LC–MS
• precipitation
• protein analysis

Financial & competing interests disclosure

A Gjelstad is a co-inventor on a pending patent application on sampling media using water-soluble biopolymers (WO2013179141 A1). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Acknowledgements

Siri Johannesen and Hilde Nilsen at Department of Pharmaceutical Bioscience, School of Pharmacy (University of Oslo) is acknowledged for assisting on Bradford Assay. Camilla Stensrud and Hilde Nilsen at Department of Pharmaceutical Bioscience, School of Pharmacy (University of Oslo) are acknowledged for sampling of whole blood.