15 Second Screening Analysis of Cyanide in Blood Serum Without Pretreatment

Importance of the Topic

Cyanide poisoning remains a critical concern in forensic toxicology, clinical emergency medicine and public safety due to its high toxicity and potential use in criminal incidents. Rapid, sensitive screening methods are essential to identify cyanide in biological samples without extensive sample preparation, reducing time-to-result and operational complexity.

Objectives and Study Overview

This study introduces a 15-second screening workflow for detecting cyanide in blood serum without conventional pretreatment. By combining probe electrospray ionization (PESI) with a direct probe ionization mass spectrometer (DPiMS-2020) and in-source collision-induced dissociation (CID), the method aims to accelerate analysis while maintaining selectivity and sensitivity.

Methodology and Instrumentation

The screening protocol involves spiking serum with potassium cyanide (10 µg/mL), followed by derivatization with taurine and naphthalene dialdehyde to yield a stable cyanide derivative (MW 300). A 10 µL aliquot of the derivatized serum is deposited on a sample plate and analyzed directly without extraction or chromatography. Key instrumentation and parameters include:

• Probe Electrospray Ionization (PESI): Ultrafine probe sampling with high-voltage ionization, enabling direct analysis of liquid or solid samples.
• Mass Spectrometer: Shimadzu DPiMS-2020 coupled to PESI; in-source CID achieved by applying â_x0088__x0092_80 V to both the desolvation line (DL) bias and Q-array bias.
• Operating Conditions: DL temperature 250 °C; heater block 35 °C; interface voltage â_x0088__x0092_2.45 kV in negative ESI mode; probe drive at 250 mm/s with 0.63 G acceleration; sampling and ionization times of 50 ms and 100 ms respectively.
• Reference Instrument: LCMS-8040 triple quadrupole mass spectrometer used to confirm product ion spectra.

Main Results and Discussion

The PESI-DPiMS-2020 workflow produces a characteristic mass chromatogram resulting from repeated sampling and ionization cycles. In-source CID fragmentation of the MW 300 derivative yields diagnostic product ions, enabling unambiguous screening for cyanide within 15 seconds. Comparison with LCMS-8040 MS/MS spectra confirms the identity of key fragments and validates structural assignments.

Benefits and Practical Applications

This method offers multiple advantages:

• Minimal Sample Preparation: No extraction or chromatographic separation needed, reducing labor and consumable costs.
• Speed: Complete analysis in under 15 seconds, facilitating high-throughput screening in forensic and clinical settings.
• Low Sample Volume: Only 10 µL of serum required, preserving scarce or precious samples.
• Versatility: Applicable to both liquid and solid matrices, supporting diverse analytical scenarios.

Future Trends and Potential Applications

Emerging developments may include expanding PESI-DPiMS capabilities to detect a wider range of toxicants and small molecules, integrating portable mass spectrometers for field deployment, and refining in-source CID parameters to enable multiplexed screening. Further automation of sample handling and data processing could enhance throughput and ease of use.

Conclusion

The integration of PESI with the DPiMS-2020 mass spectrometer and in-source CID provides a rapid, simple, and sensitive approach for screening cyanide in blood serum without pretreatment. This workflow significantly reduces analysis time and operational complexity, making it a valuable tool for forensic toxicology, emergency diagnostics and pharmaceutical quality control.

References

Chinaka S., Takayama N., Michigami Y., Ueda K. J. Chromatogr. B. 713:353–359 (1998)