Compact quadrupole time of flight mass spectrometry qtof ms

Chromatography was carried out on a Dionex UltiMate 3000 UHPLC system (Thermo Fisher, Waltham MA, USA). Separation was achieved by an Agilent Poroshell 120 EC-C₁₈ column (2.7 μm, 2.1 × 100 mm). The column temperature was set at 30 °C, and the injection volume was 2.0 μL. Elution was performed at a flow rate of 0.6 mL min⁻¹ using (A) 0.1% formic acid aqueous solution, and (B) ACN as the mobile phases. The linear gradient for phase B was as follows: 0.0 min 10% B, 1.0 min to 30% B, 4.0 min to 60% B, 4.5 min to 90% B, and then a reversion to initial conditions. In total, gradient elution time was 4.5 min, and stabilization time was 1.5 min.
Identification and quantitation of target analytes were performed on a Bruker “Compact” quadrupole time-of-flight mass spectrometry (qTOF-MS, Bremen, Germany) coupled with an Apollo II ion funnel electrospray ionization (ESI) source. Positive ion mode with the scan range from m/z 800 to 1350 was applied for ESI-qTOF-MS analysis. The ESI(+)-qTOF-MS operating parameters were as follows: dry gas flow, 10 L min; capillary voltage, −4.5 kV; dry gas temperature, 220 °C; nebulizer gas pressure, 3.5 bar. The quantitation ions of MC-YR and MC-LR were listed in Table 1. A cluster of sodium formate ions (i.e., [Na(NaCOOH)_n]⁺, n = 12 to 18) were employed to calibrate the accurate masses for high resolution qTOF-MS.

All chemical reagents and organic solvents were obtained from commercial suppliers and used without further purification. The experiments were performed in a Discover microwave apparatus (CEM Corporation, USA) and a Branson 1510 ultrasonic cleaning bath with a mechanical timer and a heater switch, 47 kHz. Thin-layer chromatography (TLC) was performed to check the purity of compounds on silica gel 60 H_F254 plates (Merck, Germany). The melting point ranges (mp) were taken on an Electrothermal IA9100 apparatus (Stone, UK) using the one-end open capillary method and were uncorrected. IR spectra (KBr discs, 500–4000 cm⁻¹) were recorded on a NEXUS 670 FT-IR spectrophotometer (Thermo Nicolet, USA). ¹H and ¹³C NMR spectra were recorded using DMSO-d₆ and CDCl₃ as solvents and tetramethylsilane (TMS) as an internal reference on an AM-400 spectrometer (Bruker, Germany) at working frequencies 400 and 100 MHz, respectively. High-resolution mass spectrometry (HRMS) analyses were carried out using a Bruker “Compact” quadrupole time-of-flight mass spectrometry (qTOF-MS, Germany) coupled with an Apollo II ion funnel electrospray ionization (ESI) source. The UV-Vis spectrum was recorded using a Spectroquant UV/VIS Pharo 300 Spectrophotometer (Merck, Germany) in the wavelength range of 160–750 nm.

All chemical reagents and organic solvents were obtained from commercial suppliers and used without further purification. Thin-layer chromatography (TLC) was performed to check the purity of compounds on silica gel 60 HF254 plates (Merck, Germany). The melting point ranges (m.p.) were taken on an Electrothermal IA9100 apparatus (Stone, UK) using the one-end open capillary method and were uncorrected. IR spectra (KBr discs, 500–4000 cm⁻¹) were recorded on a NEXUS 670 FT-IR spectrophotometer (Thermo Nicolet, USA). ¹H and ¹³C NMR spectra were recorded using DMSO-d₆ and CDCl₃ as solvents and tetramethylsilane (TMS) as an internal reference on an AM-400 spectrometer (Bruker, Germany) at working frequencies 400 and 100 MHz, respectively. High resolution mass spectrometry (HRMS) analyses were conducted using a Bruker “Compact” quadrupole time-of-flight mass spectrometry (qTOF-MS, Germany) coupled with an Apollo II ion funnel electrospray ionization (ESI) source. UV-Vis absorption and fluorescence spectra were recorded in methanol at 10 μM using UV/Visible Metertech SP-8001 and Hitachi F-2710 spectrophotometers, respectively. In both cases, cells with an optical path of 10 mm were used and the fluorescence was acquired with a slit width of 2.5 nm.