Real‐time traceability of sorghum origin by soldering iron‐based rapid evaporative ionization mass spectrometry and chemometrics

Abstract

Sorghum is an important grain with a high economic value for liquor production.Tracing the geographical origin of sorghum is vital to guarantee the liquor flavor. Soldering iron-based rapid evaporative ionization mass spectrometry (REIMS) combined with chemometrics was developed for the real-time discrimination of the sorghum's geographical origin. The working conditions of soldering ironbased ionization were optimized, and then the obtained MS profiling data were processed using chemometrics analysis methods, including principal component analysis-linear discriminant analysis and orthogonal projection to latent structures discriminant analysis (OPLS-DA). A recognition model was established, and discriminations of sorghum samples from 10 provinces in China were achieved with a correct rate higher than 90%. On the basis of OPLS-DA, the specific ions of m/z 279.2327, 281.2479, and 283.2639 had relatively strong discrimination power for the geographical origins of sorghum. The developed method was successfully applied in the discrimination of sorghum origins. The results indicated that the soldering iron-based REIMS technique combined with chemometrics is a useful tool for direct, fast, and real-time ionization of poor conductivity samples and acquisition of metabolic profiling data.

Real-Time Authentication of Camellia Oil by Rapid Evaporative Ionization Mass Spectrometry

“…The reduction was performed to ensure that the most relevant signals for each class of molecule were captured and analyzed, which would result in a more accurate statistical model. During the ionization process, fatty acids in the m/z 100-500 range and glycerophospholipids in the m/z 600-900 range were found to be dominant [38,39]. This observation can be attributed to the high abundance and low desolvation enthalpy of fatty acids and phospholipids in the oil samples.…”

Rapid evaporative ionization mass spectrometry: A survey through 15 years of applications

“…A valid alternative to investigate liquid and poorly conductive samples was also presented by Wang et al, that combined the REIMS source with an electric soldering iron as a contact heating device [20]. This instrumental setup has been mostly used in the food field for the analysis of honey, milk, sorghum, olive oil, and cream [20][21][22][23][24] but was also employed for textile and clinical applications for the analysis of lather products and plasmalogen-loaded zein • Poor discrimination of isomers or isobars nanoparticles, respectively [25,26]. Liu and colleagues performed a clear comparison between iknife and soldering iron sampling devices in terms of signal intensity for the ambient ionization of sorghum powders, in order to assess that any ion enhancer is necessary when using the soldering iron even in the case of not conductive samples, while an insufficient aerosol is generated by iknife [22].…”

Applications of ambient ionization mass spectrometry in 2022: An annual review

“… 27 Other studies aiming to improve existing techniques have introduced a plasma treatment step to the DESI pipeline to increase ion signal, 186 studied the effects of ion source geometry on the reproducibility of LAESI imaging, 187 incorporated the use of helium as a nebulizing gas into DESI and ESI, 188 and developed a post‐acquisition mass recalibration method to reduce mass drift in DESI analysis. 189 Others have built custom REIMS devices using a soldering iron to improve analysis of poorly conductive samples, 190 incorporated an online derivatization step into multiphase flow EESI for the analysis of reactive sulfur species, 191 and modified the DART source to reduce undesirable oxidation when using nitrogen gas in place of helium. 192 Some researchers have attempted to produce simpler and lower cost versions of AIMS techniques, such as using repurposed americium‐241 from smoke detectors as ion sources 193 and building miniaturized sample nebulizing devices using cheap piezoelectric materials.…”