Key wordslactam, spe, antibiotics, online, piperacillin, amoxicillin, direct, penicillin, ampicillin, water, loading, injection, gradient, valve, delay, uhplc, four, draw, cartridge, waste, flow, time, drive, analytical, eject, conditions, cube, method, cartridges, metering, external, seat, loop, switching, counts, ultrapure, negative, wastewater, parameter, anitbiotics, fragv, harald, majewsky, marius, enrichment, sample, flush, volume, slightly, phase