Phencyclidine (PCP) in Urine by GC/MS

Significance of the Topic

Accurate detection of phencyclidine (PCP) in urine is essential for compliance with federal guidelines and forensic toxicology. GC/MS provides the confirmation step required by SAMHSA, ensuring high specificity and sensitivity at sub-nanogram levels.

Objectives and Study Overview

The study aims to develop and validate a streamlined GC/MS method for confirmatory analysis of PCP in urine samples. Key goals include achieving a limit of quantitation at or below 2.5 ng/mL, demonstrating linearity up to 250 ng/mL, and meeting SAMHSA criteria for three-ion ratio confirmation.

Methodology

Sample preparation involves:

• Spiking 1 mL urine with deuterated internal standard (d5-PCP)
• pH adjustment to 6.0 with phosphate buffer
• SPE cleanup using C18 polymeric cartridges, followed by elution with methylene chloride/isopropanol/ammonium hydroxide (78:20:2)
• Evaporation to dryness, reconstitution in ethyl acetate, and injection (1 µL)

The GC method uses pressure-pulsed splitless injection and fast temperature ramping, while MS operates in electron ionization mode with selected ion monitoring (SIM) of three PCP ions (200, 242, 186) and two deuterated ions (205, 248).

Used Instrumentation

• Gas chromatograph: PerkinElmer Clarus 680 GC with Elite-5 column (12 m × 0.20 mm × 0.33 µm)
• Mass spectrometer: PerkinElmer Clarus SQ 8 with 255 L/s turbomolecular pump
• Autosampler: Pressure-pulsed splitless injector at 250 °C

Main Results and Discussion

The method achieved:

• Limit of quantitation: 2.5 ng/mL
• Limit of detection: < 1.0 ng/mL
• Linearity (R2 > 0.999) from 2.5 to 250 ng/mL
• Retention time reproducibility at 5.17 min, with ion ratios within ± 20% of standards

Fast GC oven cooling and high carrier flow enhanced sample throughput without compromising resolution or sensitivity.

Benefits and Practical Applications

This validated GC/MS procedure offers legally defensible results for workplace and forensic drug testing. It supports high-throughput analysis in clinical laboratories and meets federal confirmatory requirements.

Future Trends and Potential Uses

Emerging developments may include automated SPE, high-resolution mass spectrometry for improved selectivity, miniaturized sample prep workflows, and advanced data processing algorithms for real-time confirmation. Integration with multiplexed toxicology panels can further streamline routine screening.

Conclusion

The presented GC/MS method demonstrates robust sensitivity, precision, and compliance with SAMHSA guidelines, making it suitable for forensic and research laboratories requiring reliable PCP confirmation in urine.

References

• Baselt RC. Disposition of Toxic Drugs and Chemicals in Man. 8th Ed., Biomedical Publications, 2008.
• Mandatory Guidelines for Federal Workplace Drug Testing Programs. 73 Fed Reg 71857 (2008).
• Mandatory Guidelines for Federal Workplace Drug Testing Programs. 75 Fed Reg 22809 (2010).
• Pierce Catalog. Rockford, IL.