Securityguard cartridge kit

Glucose and lactate concentrations were determined by High-Performance Liquid Chromatography (HPLC). Samples are analyzed on a Shimadzu Prominence LC-2030C Plus with an RI detector (RID-20A). An isocratic method of 15 min on a Rezex ROA-Organic Acid H+ (8%) column (Phenomenex—part number 00F-0138-K0 + SecurityGuard Cartridge Kit (KJ0-4282) + SecurityGuard Cartridges Carbo-H 4 × 3.0 mm ID (AJ0-4490)) was used. The mobile phase was 5 mM sulfuric acid (Chem-lab CL00.2653.0050). The column temperature was 60°C and the temperature of samples was 4°C. The detection of glucose was done with an RI detector and the detection of lactate with a UV detector (210 nm).
Carboxylic acids (acetate, propionate, butyrate, iso-butyrate, valerate, iso-valerate, and caproate) were determined by gas chromatography (GC) with flame ionization detection (FID) as described by Candry et al. (2020) (link) after the extraction of acids into diethyl ether as described by Andersen et al. (2014) (link).
The gaseous head space composition was analyzed using a Compact Gas Chromatograph (Global Analyser Solutions, Breda, Netherlands), equipped with a Molsieve 5A pre-column and Porabond column (CH₄, O₂, H_2, and N₂), and a Rt-Q-bond pre-column and column (CO₂). Concentrations of gases were determined using a thermal conductivity detector.

The LC-MS/MS analysis was performed by Agilent 6490 (Agilent Technologies, Santa Clara, CA, USA) coupled with Agilent 1260 HPLC system (Agilent Technologies). The analyte was separated on a Gemini 5 μm C18 110A column (150 × 2 mm i.d., 5 μm, Phenomenex, Torrence, CA, USA) with SecurityGuard Cartridge Kit (Phenomenex). An isocratic mobile phase composed of 0.1% aqueous formic acid and methanol (50:50 v/v %) was used with a flow rate of 0.3 mL/min. The column oven temperature was 40 °C and the total run time was 6 min.
The electrospray ionization (ESI) source was operated in positive mode, and the mass spectrometer was operated in the multiple reaction monitoring (MRM) mode with a dwell time of 200 ms per MRM channel. Gas temperature, gas flow rate, and nebulizer gas pressure were set at 220 °C, 17 L/min, and 45 psi, respectively. The selected precursor/product ion pairs were m/z 174.4 → 165.8 for nafamostat and 177.4 → 168.9 for IS. The fragment voltage was 380 V, and the collision energy was set at 11 eV for both nafamostat and IS. The mass spectrometric data were processed by MassHunter Quantitative Analysis (Agilent Technologies).