Semester

Spring

Date of Graduation

2026

Document Type

Thesis (Campus Access)

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Chemistry

Committee Chair

Lisa Holland

Committee Co-Chair

Harry Finklea

Committee Member

Stephen Valentine

Abstract

Capillary electrophoresis provides rapid separations and consumes only nanoliter volumes of sample per run. This separation technique is important for biomolecules, including proteins. However, non-specific adsorption of proteins to the fused silica capillary limits the utility of the method. Several coatings have been developed to address this limitation, including semi-permanent phospholipid coatings. Semi-permanent phospholipid coatings are prepared in-capillary each day and may be regenerated between runs. An alternative to semi-permanent phospholipid coatings are polymerized phospholipid coatings which can be fabricated and permanently stored for several months. In this way, no capillary pretreatment is required prior to electrophoretic separation. In this report, phospholipids are polymerized in-situ with ultraviolet irradiation to create a permanently coated capillary which can be stored and reused. The permanent phospholipid coating was characterized by measuring the electroosmotic flow using a previously reported method based on the profile of three injections of a neutral marker. Compared to an unmodified fused silica capillary which had an electroosmotic flow of 53.00 ± 0.01 ×10−5 cm2/Vs, the capillary containing a polymerized phospholipid at the surface has a decreased electroosmotic flow of 3.34 ± 0.02 ×10 −5 cm2 /Vs. The stability of the coating is characterized by measuring the reproducibility of the electroosmotic flow within day and across day and has a relative standard deviation of 1%. The polymerized phospholipid coating is stable between pH 4-7; however, the electroosmotic flow reveals a pH dependence. The utility of this capillary modified with the polymerized phospholipid coating is demonstrated with separations of cationic proteins and anionic alpha 1-acid glycoprotein at various pH values.

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