Date of Award
5-2026
Document Type
Dissertation
Committee Chair/Advisor
R. Kenneth Marcus
Committee Member
Christopher Chouinard
Committee Member
George Chumanov
Committee Member
Brian Powell
Abstract
Inductively coupled plasma mass spectrometry (ICP-MS) is a widely employed technique in analytical chemistry for the detection of trace level (sub parts-per-trillion to parts-per-billion) atomic detection. Despite its usefulness in quantifying small quantities of analytes, there are many challenges that arise with the employment of this technique as matrix effects, lack of structural information, and difficulties with sample preparation can hinder the usefulness of the technique. The use of pre-sampling techniques to alleviate these limitations is therefore of great importance. No sampling technique is comprehensive, as sample types have different challenges. Therefore, pre-sampling methods need to be customized based on the intended application.
Environmental swipes and dried blood spot (DBS) cards are collection substrates used to absorb samples through swiping or submerging a cloth swipe or pricking a finger to deposit blood samples onto a card. The samples are adsorbed onto the substrate for easy storage and transportation. This ease of collection and storage makes them a desirable method for blood samples and remote collection; however, low sample volumes and inefficient removal techniques hinder detection. Typically, the swipes or DBS cards are acid digested and/or ashed then resuspended into solution before detection via ICP-MS. This can be inefficient, increase the interfering background elements, limit the sensitivity of detection, and be time consuming. In lieu of traditional methods, the use of a microextraction technique for direct extraction is presented here as a time efficient method of analyte extraction. Mn, Fe, Co, Cu, Zn, Ag, Nd, Gd, and Yb were extracted from cloth swipes and Cd, Hg, and Pb were extracted from DBS cards with real blood samples. This technique proved to be an efficient extraction method with minimal sample preparation time (less than four minutes) for the quantification of multi-element samples via ICP-MS.
Cell culture media (CCM) is the essential nutrient source for any cell growth and is carefully curated to maximize the growth and therapeutic protein production process. CCM contains essential nutrients such as amino acids, antibiotics, carbohydrates, vitamins, and inorganic salts. Metals are an important part of these nutrients, specifically added as vitamins and inorganic salts, and are required for numerous cellular processes. It is natural to think that the chemical form in which these metals exist may affect their function within the biological processes they are required for; therefore, a method to speciate and quantify the metals as a means of quality control is of utmost importance to cell culture researchers. The use of microbore polypropylene-4 (PP4) capillary channeled polymer (C-CP) fiber columns for a reversed-phase (RP) separation of free and ligated species was used to speciate CCM metals on a high-performance liquid chromatography (HPLC) before quantification via ICP-MS. This method enabled quality control monitoring of manufactured CCM, determined deviations in the CCM effects on cell culture growth, and how the chemical speciation of metals in the cellular supernatant changes throughout a Chinese hamster ovary (CHO) cell growth for a total mass metals balance.
Exosomes are a subset of extracellular vesicles (EVs) that range in size from 30-200 nm. These are vesicles that are excreted by all cell types and carry with them the genetic information from their parent cells. This makes them of interest for disease diagnosis, by identifying the contained genetic information, and for the study of disease propagation, by quantifying the rate of exosome excretion. Typical methods of quantification have high LODs and can be inaccurate since the presence of protein can cause the signal to be over or underestimated. Herein, we use a hydrophobic interaction chromatography (HIC) modality paired with C-CP fiber tips to isolate EVs from urine. The EVs are then labeled with YbCl3 via a chelation reaction with the phosphate groups in the phospholipid bilayer. Yb detection via ICP-MS enables indirect exosome detection and quantification without interference. This allows for the quantification of bulk exosomes down to the hundreds to thousands of exosomes per mL concentration. Additionally, this method of quantification is coupled with a mass cytometry-based method of attaching lanthanide labeled (145Nd) antibodies (anti-CD81) to the surface proteins on the exosomes to characterize the exosomes.
The use of these pre-sampling methods allows for the identification and differentiation of analyte information combined with the ultra-sensitive detection of the analytes via ICP-MS. This work expands the use of ICP-MS to a wider array of fields while also increasing the ease of analysis for current applications.
Recommended Citation
Stouffer, Cameron J., "Interfacing Pre-Sampling Platforms with ICP-MS for High Sensitivity Atomic Detection in Biological and Environmental Matrices" (2026). All Dissertations. 4233.
https://open.clemson.edu/all_dissertations/4233
Author ORCID Identifier
0000-0003-2342-7915