Thin-layer chromatography/direct analysis in real time time-of-flight mass spectrometry and isotope dilution to analyze organophosphorus insecticides in fatty foods

Applications of DART‐MS for food quality and safety assurance in food supply chain

“…SPE are divided into normal phase SPE, reversed phase SPE, ion exchange SPE. Multifarious solvents, for example, acetonitrile (Kiguchi et al, 2014), n-hexane (Kalachova et al, 2011), n-hexane/dichloromethane (3:1, v/v) (Drabova et al, 2013), hexane/diethylether (96:4, v/v) (Moravcova et al, 2012), and acetone/n-hexane (3:1, v/v) (Kiguchi et al, 2014) have been used based on the polarity of analytes. The most pivotal influence factor of SPE is the sorbent materials, including silica gels (e.g., C 18 ) (Kalachova et al, 2011), polymers (e.g., styrene-divinylbenzene) (Drabova et al, 2013), inorganics (e.g., graphite carbon) (Kiguchi et al, 2014), and composites (e.g., strong anion exchange [SAX]/primary secondary amine [PSA]) (Kiguchi et al, 2014).…”

“…Developing solvent of TLC/HPTLC need to be selected based on analyte polarity, for example, chloroform/ methanol (9:1, v/v) for curcumin (Kim & Jang, 2009), n-hexane/ ethyl acetate/acetic acid (5:3:1, v/v/v) for phenolic compounds (Morlock, Ristivojevic, & Chernetsova, 2014), hexane/acetone (3:1, v/v) for insecticides (Kiguchi et al, 2014), and acetone/ water (1:1) for aflatoxin (Busman et al, 2014). According to the property of the analytes, different lasers with specified wavelengths are utilized for localizing analyte band, including UV light (Chernetsova & Morlock, 2012) and white light (Kiguchi et al, 2014). DART ion source with integrated multiple lasers for desorption performs well with good spatial resolution when coupled to TLC .…”

Instrument platforms for thin-layer chromatography

“…25 [109]. JEOL manufacture a DART source equipped with an autoslider that can scan thin-layer plates cut into strips with a width of about 1 cm [110]. The resolution of scanned separations is limited by the cone diameter of the source beam and sensitivity by surface sampling.…”

“…Lower sample detectability was achieved using matrix-assisted sampling by applying a solvent matrix (glycerol) to the layer prior to measurement or by cutting the layer through the sample zone and exposing the edge of the layer to the source beam (manual methods) [108,111]. Quantification is improved by using stableisotope-dilution analysis [108,110].…”

Quantitative surface scanning by Direct Analysis in Real Time mass spectrometry

“…Relative standard deviations ( %RSD , n = 5) of 17% for 1 μg/zone and 12% for 10 μg/zone were determined, and the possibility for quantitation in a scanning mode was demonstrated, although HMF was not chromatographed but only deposited on the substrate. Another TLC autoslider for the horizontal DART ion source was used for the determination of organophosphorus insecticides using internal standard correction, yielding a good analytical response (R 2 = 0.9796–0.9998, 0.05–25.0 ng/zone) with mean recoveries of 74–109% (mean % RSD = 11%) . Hence, with few exceptions, quantitation was performed using internal standard correction.…”