The conventional method of using liquid chromatography to determine the composition of a gaseous mixture entails dissolving vapors in a suitable solvent, then obtaining a chromatograph of the resulting solution. We studied the direct introduction of a gaseous sample into a C18 reversed-phase column, followed by separation of the components by HPLC with UV detection. Since the chromatography was performed at high pressure, vapors readily dissolved in the eluent and the substances separated in the column as effectively as in liquid samples. Samples were injected into the column in two ways: a) through the valve without a flow stop; b) after stopping the flow and relieving all pressure. We showed that an injectable gas volume could reach 70% of column dead volume. When an injected gaseous sample volume was less than 10% of the column dead volume, the resulting peaks were symmetrical and the column efficiency was high.
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http://dx.doi.org/10.1016/j.chroma.2017.04.042 | DOI Listing |
Clin Rheumatol
January 2025
Department of Rheumatology, Guang'anmen Hospital, Chinese Academy of Chinese Medical Sciences, Beijing, People's Republic of China.
Introduction/objectives: Sjogren's syndrome (SS) is a chronic inflammatory and difficult-to-treat autoimmune disease. Timosaponin AIII (TAIII), a plant-derived steroidal saponin, effectively inhibits cell proliferation, induces apoptosis, and exhibits anti-inflammatory properties. This study explored the mechanisms of action of TAIII in SS treatment by studying gut microbiota and short-chain fatty acids (SCFAs) using fecal metabolomics.
View Article and Find Full Text PDFZhongguo Dang Dai Er Ke Za Zhi
January 2025
Department of Pediatrics, Third People's Hospital of Longgang District of Shenzhen, Shenzhen, Guangdong 518020, China.
Objectives: To explore the role of berberine (BBR) in ameliorating coronary endothelial cell injury in Kawasaki disease (KD) by regulating the complement and coagulation cascade.
Methods: Human coronary artery endothelial cells (HCAEC) were divided into a healthy control group, a KD group, and a BBR treatment group (=3 for each group). The healthy control group and KD group were supplemented with 15% serum from healthy children and KD patients, respectively, while the BBR treatment group received 15% serum from KD patients followed by the addition of 20 mmol/L BBR.
Nutr Metab (Lond)
January 2025
Shenzhen Center for Chronic Disease Control, No. 2021 Buxin Road, Luohu District, Shenzhen, 518020, China.
Background: Serum vitamin D deficiency is intricately linked to metabolic disorders, however, evidence on its association with continuous metabolic risk in children and adolescents remains insufficient. This study aims to elucidate the relationship between serum vitamin D levels and continuous metabolic risk.
Methods: The cross-sectional analysis involved 4490 participants aged 6 ~ 18, and the longitudinal investigation included 1398 individuals aged 6 ~ 12 years.
Nat Protoc
January 2025
Department Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany.
Deep and accurate proteome analysis is crucial for understanding cellular processes and disease mechanisms; however, it is challenging to implement in routine settings. In this protocol, we combine a robust chromatographic platform with a high-performance mass spectrometric setup to enable routine yet in-depth proteome coverage for a broad community. This entails tip-based sample preparation and pre-formed gradients (Evosep One) combined with a trapped ion mobility time-of-flight mass spectrometer (timsTOF, Bruker).
View Article and Find Full Text PDFSci Rep
January 2025
Pharmaceutical Chemistry Department, Faculty of Pharmacy, Horus University, New Damietta, 34517, Egypt.
RP-HPLC technique was developed and optimized for simultaneous identification and estimation of nirmatrelvir (NIR) and ritonavir (RIT) in their new copackaged tablet. Stability of nirmatrelvir (NIR) was studied after exposure to different five stress conditions; alkali, acid, heat, photo and oxidation degradation. The chromatographic separation was achieved using VDSpher PUR 100 ODS (4.
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