Trace enrichment of phenylcarboxylic acids from a model biological fluid and serum of human blood

• Published in: Journal of separation science Vol. 42; no. 16; pp. 2706 - 2714
• Main Authors: Popov, Alexander Y., Blinnikova, Zinaida K., Tsyurupa, Maria P., Davankov, Vadim A.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2019
• Subjects: Acids; Blood; Body Fluids - chemistry; Carboxylic Acids - blood; Cartridges; Chromatography, High Pressure Liquid; Crosslinking; Dihydroxybenzoic acid; Humans; hyper‐cross‐linked polysturene; Liquid chromatography; Models, Biological; phenylcarboxylic acids; Phenyls; Polystyrene resins; restricted access materials; Solid Phase Extraction; Sorbents; Superposition (mathematics); phenylcarboxylic acids; hyper-cross-linked polysturene; restricted access materials; solid-phase extraction
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.201900258

The study was focused on the development of a solid‐phase extraction protocol for seven phenylcarboxylic acids from albumin solutions by using unmodified hyper‐cross‐linked polystyrene restricted access materials with crosslinking degrees varying from 100 to 400% (four of the acids are known to be markers of sepsis). The breakthrough volume of the most hydrophilic 3,4‐dihydroxybenzoic acid rises as the sorbent bridging extent grows. Inversely, the breakthrough volume of the most hydrophobic 3‐phenylpropionic acid was found to decrease considerably when the degree of crosslinking exceeds 200%. This unusual pattern is because of the superposition of two opposite tendencies. Increasing substitution extent of phenyls facilitates their π‐π‐interactions with polar compounds whereas rising density of the network reduces the accessibility of sorption sites to all solutes. Mini‐cartridges containing 30 mg of an optimal sorbent take up the acids completely and reversibly, the recoveries being close to 100% even in the presence of high concentrations of albumin. By coupling the developed solid‐phase extraction with high‐performance liquid chromatography and diode array detection technique, we managed to determine quantitatively phenylcarboxylic acids in the serum of a healthy patient blood, and the recoveries varied from 93 to 100% while the limit of quantification was (4–9) × 10−7 M.