Direct Probe Ionization Mass Spectrometer - Application Notebook

Significance of Topic

Mass spectrometry workflows typically require extensive sample preparation and chromatography, which limit throughput and prevent direct analysis of heterogeneous or solid samples. The DPiMS-8060, combining ultrafine probe electrospray ionization (PESI) with a tandem quadrupole MS, addresses these challenges by enabling direct, rapid, and sensitive analysis of liquids, solids, and biological tissues with minimal or no pretreatment.

Objectives and Study Overview

This collection of application studies demonstrates the DPiMS-8060’s capabilities across eight use cases: sensitive screening of tetrodotoxin in pufferfish tissues; profiling 74 pesticides in agricultural produce; rapid drug detection in forensic specimens; high-throughput 64-drug screening in whole blood; chromatography-free quantitation of everolimus and abiraterone in plasma; ex vivo metabolomics of brain and liver tissues; and localized anthocyanin mapping in flower petals. Each study benchmarks direct probe ionization against conventional LC-MS/MS methods for speed, sensitivity, and robustness.

Methodology and Instrumentation

All experiments employed the Shimadzu DPiMS-8060 with PESI probe (tip ~700 nm) and LCMS-8060 triple-quadrupole MS. Typical ionization conditions: ±2.3–3.0 kV PESI voltage, rapid MRM or product-ion scans, and simple sample prep (direct slicing of solids, light wetting with 50% ethanol, or single-step dilution/deproteinization). Scheduled MRM libraries covered up to 80 analytes. Per-sample analysis times ranged from 0.2 to 3.2 min.

Main Results and Discussion

· Tetrodotoxin in pufferfish muscle, skin, liver, and ovary detected via MRM (m/z 320→162) with LOD 0.47 ng/mL, LOQ 1.57 ng/mL (R²>0.997), 0.5 min per sample.
· Seventy-four pesticides in cucumber screened at 1–10 ppb sensitivity; 36 compounds showed linearity (R²>0.98); full panel profiled in 1.5 min.
· The synthetic opioid MT-45 and its metabolites were detected directly in brain, lung, heart, liver, and kidney; quantitative MRM results (R²>0.996) matched LC-MS/MS, analysis in 0.5 min vs 20 min.
· A 64-drug panel in whole blood was screened in 3.2 min via scheduled SRM (vs >30 min LC-MS) with LOQs of 1–50 ng/mL.
· Everolimus and abiraterone were quantified in plasma after simple deproteinization: linear calibration (R²>0.986), ≤20% RSD, total prep and analysis in ~10 min.
· Ex vivo brain and liver metabolomics of model mice distinguished control vs treated/failing tissues by PCA/PLS-DA using 26 targeted metabolites, revealing biomarkers like glutamic acid and taurine.
· Local anthocyanin pigment (cyanidin-3-glucoside) mapping in petunia petals by product-ion scan (m/z 449→287) confirmed pigment distribution without extraction.

Benefits and Practical Applications

• Reduces analysis time by up to 97.5% versus conventional LC-MS/MS.
• Eliminates complex sample prep and chromatography, lowering costs and consumables.
• Enables direct, spatially resolved analysis of solids, tissues, and live specimens.
• Suitable for routine QA/QC in food safety, point-of-care forensics and clinical toxicology, and high-throughput bioanalysis.

Future Trends and Potential Applications

• Integration into portable, point-of-care mass spectrometry systems.
• Expansion to broader analyte libraries, including emerging contaminants and untargeted metabolomics.
• Real-time monitoring of in vivo biochemical processes and single-cell assays.
• Coupling with high-resolution MS for comprehensive discovery workflows.

Conclusion

The DPiMS-8060, leveraging direct probe electrospray ionization, delivers rapid, sensitive, and versatile MS analysis across diverse matrices, streamlining workflows and opening new opportunities in food safety, forensic and clinical toxicology, and life-science research.

Reference

1. Hiraoka K. et al. Rapid Commun. Mass Spectrom. 2007, 21, 3139–3144.
2. Zaitsu K. et al. Anal. Chem. 2016, 88, 3556–3561.
3. Hayashi Y. et al. Anal. Chem. 2018, 90, 4695–4701.
4. Usui K. et al. Drug Test Anal. 2018, 10, 1033–1038.
5. Shimadzu application notes B102, B90, B87, B88, B89 (2019).