TY - JOUR

T1 - Split-Ring Resonator Based Sensor for the Detection of Amino Acids in Liquids

AU - Dehning, Kirsten J.

AU - Hitzemann, Moritz

AU - Gossmann, Alexander

AU - Zimmermann, Stefan

N1 - Funding Information: This research was funded by Guangzhou Science and Technology Planning Project (202102080024).

PY - 2023/1

Y1 - 2023/1

N2 - Amino acids belong to the most important compounds for life. They are structural components of proteins and required for growth and maintenance of cells. Essential amino acids cannot be produced by the organism and must be ingested through the nutrition. Therefore, the detection of amino acids is of great interest when analyzing cell culture media and nutrition. In this work, we present a split-ring resonator as a simple but sensitive detector for amino acids. Split-ring resonators are RLC resonant circuits with a split capacitance and thus a resonance frequency that depends on the electromagnetic properties of a liquid sample at the split capacitance. Here, the split capacitance is an interdigital structure for highest sensitivity and covered with a fluidic channel for flow through experiments. First measurements with a vector network analyzer show detection limits in the range from 105 µM for glutamic acid to 1564 µM for isoleucine, depending on the electromagnetic properties of the tested amino acids. With an envelope detector for continuous recording of the resonance frequency, the split-ring resonator can be used in ion chromatography. At a flow rate of 0.5 mL/min, it reaches limits of detection of 485 µM for aspartic acid and 956 µM for lysine.

AB - Amino acids belong to the most important compounds for life. They are structural components of proteins and required for growth and maintenance of cells. Essential amino acids cannot be produced by the organism and must be ingested through the nutrition. Therefore, the detection of amino acids is of great interest when analyzing cell culture media and nutrition. In this work, we present a split-ring resonator as a simple but sensitive detector for amino acids. Split-ring resonators are RLC resonant circuits with a split capacitance and thus a resonance frequency that depends on the electromagnetic properties of a liquid sample at the split capacitance. Here, the split capacitance is an interdigital structure for highest sensitivity and covered with a fluidic channel for flow through experiments. First measurements with a vector network analyzer show detection limits in the range from 105 µM for glutamic acid to 1564 µM for isoleucine, depending on the electromagnetic properties of the tested amino acids. With an envelope detector for continuous recording of the resonance frequency, the split-ring resonator can be used in ion chromatography. At a flow rate of 0.5 mL/min, it reaches limits of detection of 485 µM for aspartic acid and 956 µM for lysine.

KW - amino acids

KW - conductivity

KW - relative permittivity

KW - resonance frequency

KW - split-ring resonator

KW - SRR

UR - http://www.scopus.com/inward/record.url?scp=85146581891&partnerID=8YFLogxK

U2 - 10.3390/s23020645

DO - 10.3390/s23020645

M3 - Article

C2 - 36679444

AN - SCOPUS:85146581891

VL - 23

JO - Sensors

JF - Sensors

SN - 1424-8220

IS - 2

M1 - 645

ER -