Pressurized nano-liquid-junction interface for coupling capillary electrochromatography and nano-liquid chromatography with mass spectrometry.

A new nano-liquid-junction interface for coupling both capillary electrochromatography (CEC) or nano-liquid chromatography (nano-LC) with mass spectrometry (MS) was studied. The interface was a smallT piece of polymeric material where capillary column and tip capillary were positioned at 180owhilethe third exit (at 90o) was occupied by a capillary delivering a liquid-assisting spray ionization for CECexperiments or by the electrode for the high voltage spray for nano-LC. Experiments were carried outanalyzing mixtures of some organophosphorus pesticides (OPPs) or anti-inflammatory and related acidicdrugs with MS detection in positive or negative ion mode, respectively. Analyzed OPPs compounds werebaseline resolved utilizing the novel interface in both nano-LC and CEC obtaining good sensitivity andrepeatability. For CEC-MS, the limits of detection ranged between 0.03 and 6.80 g/mL and the intra-dayrepeatability was RSD <3.8% and <13% for the retention times and peak areas, respectively. The interfacewas easy to handle and good reproducibility, between 2.5 and 3.5% for the retention time and <10% forthe efficiencies, was obtained when the interface was installed by two different analysts. Furthermore, itcould be used for both CEC and nano-LC.