an Agilent (Waldbronn,
Germany) 1290 series Infinity 2D-LC system was used for liquid chromatography
and UV–vis detection. The system included two binary pumps
(G4220A); one 1200 series isocratic pump (G1310A); a 1290 series autosampler
(G4226A) equipped with a 20-μL injection loop; two thermostated
column compartments (G1316C), in one of which an 8-port, 2-position
2D-LC valve was installed (G4236A); and one diode-array detector (DAD,
G4212A) equipped with an Agilent Max-Light Cartridge Cell (G4212-60008,
10 mm path length, Vdet = 1.0 μL).
The injector needle drew and ejected at a speed of 10 μL·min–1, with a two second equilibration time. All tubing
was fabricated of stainless steel (SS). The chromatographic and UV–vis
systems were controlled using Agilent OpenLAB CDS Chemstation Edition
(Rev. C.01.04 [35]) software. For MS detection, a Bruker (Bremen,
Germany) MicroQ-ToF mass spectrometer was used. The mass spectrometer
was controlled by Bruker Daltonics micrOTOF control Compass 1.3 for
micrOTOF-sr1 version 2.0 on a separate computer. Data were extracted
using Bruker Daltonics Data Analysis, version 4.0 SP4 build 281.