We developed a novel on-column micro gas chromatography (microGC) detector using capillary based optical ring resonators (CBORRs). The CBORR is a thin-walled fused silica capillary with an inner diameter ranging from a few tens to a few hundreds of micrometers. The interior surface of the CBORR is coated with a layer of stationary phase for gas separation. The circular cross section of the CBORR forms a ring resonator and supports whispering gallery modes (WGMs) that circulate along the ring resonator circumference hundreds of times. The evanescent field extends into the core and is sensitive to the refractive index change induced by the interaction between the gas sample and the stationary phase. The WGM can be excited and monitored at any location along the CBORR by placing a tapered optical fiber against the CBORR, thus enabling on-column real-time detection. Rapid separation of both polar and nonpolar samples was demonstrated with subsecond detection speed. Theoretical work was also established to explain the CBORR detection mechanism. While low-nanogram detection limits are observed in these preliminary tests, many methods for improvements are under investigation. The CBORR is directly compatible with traditional capillary GC columns without any dead volumes. Therefore, the CBORR-based muGC is a very promising technology platform for rapid, sensitive, and portable analytical devices.
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http://dx.doi.org/10.1021/ac702389x | DOI Listing |
Drug Test Anal
July 2024
Department of Biological and Environmental Sciences, Queensland University of Technology, Brisbane, Australia.
Previous liquid chromatography/mass spectrometry (LC/MS) methods for the detection of insulin and other similar peptide hormones in equine plasma relied on the use of antibody affinity extraction. As a result, these methods were not suitable for routine high-throughput analysis. A solid-phase extraction (SPE) method incorporating size exclusion as well as reversed-phase interactions allows the selective extraction of peptide hormones such as adrenocorticotropic hormone (ACTH), insulin and their synthetic analogues from equine plasma with approximately 80% extraction efficiencies.
View Article and Find Full Text PDFChem Sci
November 2023
CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 China
Single-cell multi-omics analysis can provide comprehensive insights to study cell-to-cell heterogeneity in normal and disease physiology. However, due to the lack of amplification technique, the measurement of proteome and metabolome in the same cell is challenging. Herein, a novel on-capillary alkylation micro-reactor (OCAM) was developed to achieve proteo-metabolome profiling in the same single cells, by which proteins were first covalently bound to an iodoacetic acid functionalized open-tubular capillary micro-reactor sulfhydryl alkylation reaction, and metabolites were rapidly eluted, followed by on-column digestion of captured proteins.
View Article and Find Full Text PDFAnal Chim Acta
July 2023
Analytical Chemistry group, van't Hoff Insititute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098XH, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam, van't Hoff Insititute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098XH, Amsterdam, the Netherlands. Electronic address:
Size-exclusion chromatography (SEC) employing aqueous mobile phases with volatile salts at neutral pH combined with native mass spectrometry (nMS) is a valuable tool to characterize proteins and protein aggregates in their native state. However, the liquid-phase conditions (high salt concentrations) frequently used in SEC-nMS hinder the analysis of labile protein complexes in the gas phase, necessitating higher desolvation-gas flow and source temperature, leading to protein fragmentation/dissociation. To overcome this issue, we investigated narrow SEC columns (1.
View Article and Find Full Text PDFJ Chromatogr A
July 2021
Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan; Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan. Electronic address:
Miniaturization of column diameter in liquid chromatography is one of the major trends in separation sciences toward single-cell proteomics and metabolomics. Micro/nanoscale open tubular (OT) capillaries are promising tools for efficient separation analyses of the ultra-small volume of samples. However, highly sensitive and label-free on-column detection is still challenging for such ultra-small capillaries.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2021
Ryerson Analytical Biochemistry Laboratory (RABL) Department of Chemistry and Biology, Faculty of Science Ryerson University, Toronto M5B 2K3, Canada.
The alkaline phosphatase-streptavidin enzyme amplification conjugate (APSA) was diluted and quantified to the equivalent of one enzyme molecule injected on column by monitoring the production of excess adenosine from adenosine monophosphate (AMP) using sensitive and selective enzyme-linked mass spectrometric assay. The APSA enzyme conjugate has a mass of about 195 kDa and catalyzed the production of millions of enzyme products over the course of incubation that may be sensitively quantified by liquid chromatography, electrospray ionization, and mass spectrometry. APSA enzyme conjugate from fg/mL to ag/mL alongside 0 g/mL (control) was incubated with the substrate 1 mM AMP for 2 h in free solution before collecting a 1 μL of sample of the enzyme product adenosine for injection and analysis by LC-MS.
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