Pesticide analysis at ppt concentration levels: coupling nano-liquid chromatography with dielectric barrier discharge ionization-mass spectrometry

Abstract

We report the coupling of nano-liquid chromatography (nano-LC) with an ambient dielectric barrier discharge ionization (DBDI)-based source. Detection and quantification were carried out by high-resolution mass spectrometry (MS), using an LTQ-Orbitrap in full scan mode. Despite the fact that nano-LC systems are rarely used in food analysis, this coupling was demonstrated to deliver extremely high sensitivity in pesticide analysis, with limits of detection (LODs) as low as 10 pg/mL. In all cases, the limits of quantification (LOQs) were compliant with the current EU regulation. An excellent signal linearity over up to four orders of magnitude was also observed. Therefore, this method can easily compete with conventional GC-(EI)-MS or LC-ESI-MS/MS methods and in some cases outperform them. The method was successfully tested for food sample analysis, with apples and baby food, extracted using the QuEChERS approach. Our results demonstrate an outstanding sensitivity (at femtogram level) and reproducibility of the nano-LC-DBDI coupling, capable of improving routine pesticide analysis. To the best of our knowledge, this is the most sensitive and reproducible plasma-MS-based method for pesticide analysis reported to date.

Direct Coupling of Solid-Phase Microextraction with Mass Spectrometry: Sub-pg/g Sensitivity Achieved Using a Dielectric Barrier Discharge Ionization Source

“…It is also among the most sensitive, with a sub-pg/mL. The LODs achieved in this study are lower or equal than LODs obtained with the nano-LC-DBDI-MS coupling recently reported [30]. The coupling of SPME with mass spectrometry we report here has several novel aspects.…”

“…The fibers can be manually introduced into the desorption chamber, because the only relevant geometric parameter to be controlled to obtain high reproducibility of the results are independent of the positioning of the SPME, namely the DBDI parameters (inter-electrode distance, applied voltage, operating frequency) and the desorption parameters (temperature, chamber inner diameter). Optimal ionization conditions (i.e., highest ion abundance) were achieved with optimized electrode positions [30]. The ion abundance is maximized for a specific electrode position, which was found to be virtually independent of the analyte type.…”

Theory and Practice of UHPLC and UHPLC–MS

“…Food products reach the consumer through human handling and action, which can introduce the presence of exogenous molecules that could endanger human health or impair the food quality. The second part of Table 9.4 describes selected recent research works in nano-LC and CLC regarding the determination of harmful compounds in food matrices such as antibiotics (LombardoAgüí et al, 2011;Ruiz-Viceo et al, 2012;D'Orazio et al, 2012a;Quesada-Molina et al, 2013;Liu et al, 2016), drugs (Berlioz-Barbier et al, 2015), pesticides (Mirabelli et al, 2016;Kruve et al, 2011;Moreno-González et al, 2011;Gure et al, 2014Gure et al, , 2015, mycotoxins (Arroyo-Manzanares et al, 2011Aqai et al, 2011;Liu et al, 2013), and phthalates (Muñoz-Ortuño et al, 2012).…”

“…Two exciting applications regarding the determination of pesticides in food matrices both employed lab-made interfaces to couple nano-LC/CLC with MS. Mirabelli et al (2016) published their results obtained by using an ambient dielectric barrier discharge ionizationebased source, whereas Kruve et al (2011) described a microfabricated heated nebulizer chip for atmospheric pressure photoionization combined with a 300 mm I.D. capillary column.…”

An overview to nano‐scale analytical techniques: Nano‐liquid chromatography and capillary electrochromatography

“…These two microfluidic techniques have been successfully used for the separation of a large number of compounds including peptides, proteins, enantiomers, drugs, herbicides, pollutants, hormones, estrogens, nutraceuticals, etc. .…”