A Simplified and Streamlined Approach to Solid Phase Extraction using Strata™-X-Drug B for SAMHSA’s Low Cutoff Drugs of Abuse Panel

Significance of the Topic

Effective monitoring of drugs of abuse at low cutoff levels is critical in forensic toxicology, workplace safety, rehabilitation and law enforcement. Streamlined sample preparation methods contribute to faster turn-around times, reduced solvent consumption and minimized user error while ensuring regulatory compliance with SAMHSA’s updated criteria.

Aims and Study Overview

This work aimed to develop a unified solid phase extraction (SPE) protocol capable of isolating 11 drugs across six SAMHSA-regulated classes (opiates, 6-MAM, PCP, amphetamines, marijuana metabolites and cocaine metabolites) at their current low cutoff thresholds. The goal was to employ a single sorbent and minimal extraction variants to simplify training and boost laboratory throughput.

Methodology

Urine samples were spiked at 40 %, 100 % and 125 % of respective SAMHSA cutoff levels. Class-specific pretreatments (enzymatic hydrolysis, pH adjustment or oxidative conversion) were applied, then samples were loaded onto 60 mg/6 mL Strata-X-Drug B cartridges without prior conditioning or equilibration. The SPE protocol comprised:

• Load: pretreated urine
• Wash 1: aqueous buffer or organic mixture
• Wash 2: methanol or acetonitrile-based wash
• Elution: ethyl acetate/isopropanol/ammonium hydroxide

Post-extraction, samples were evaporated and reconstituted for analysis. GC/MS used a Zebron ZB-Drug-1 column in SIM mode; LC/MS employed Kinetex C18 or PFP core-shell columns in positive ESI mode.

Used Instrumentation

• SPE: Strata-X-Drug B 60 mg/6 mL tubes
• GC/MS: Zebron ZB-Drug-1 (10 m × 0.18 mm × 0.18 µm), SIM detection
• LC/MS: Kinetex 2.6 µm C18 or PFP columns (50 × 2.1 mm), ESI+ detection

Main Results and Discussion

Omitting sorbent conditioning did not compromise performance and reduced solvent use and hands-on time. Recoveries for all analytes ranged from 96 % to 102 %, with RSDs below 3 % and linearity coefficients above 0.995. Both GC/MS and LC/MS workflows delivered clean extracts and clear chromatographic separation, though LC/MS offered substantially shorter run times and higher sample throughput.

Benefits and Practical Applications

• Single-sorbent approach for all SAMHSA analytes
• Three streamlined SPE methods instead of multiple protocols
• Reduced solvent consumption and processing time
• Lower risk of user error and simplified training
• High recovery, precision and method linearity at low cutoffs

Future Trends and Opportunities

Automation of SPE in 96-well formats, coupling with high-resolution MS and multiplexed detection will further enhance throughput. Development of novel sorbent chemistries could extend coverage to emerging designer drugs. Miniaturization and on-line SPE-LC/MS workflows promise real-time monitoring applications.

Conclusion

The Strata-X-Drug B sorbent offers a robust, simplified workflow for extraction of diverse drugs of abuse at stringent SAMHSA cutoff levels. Eliminating conditioning steps and consolidating methods enhances efficiency without sacrificing analytical performance, supporting high-volume forensic and workplace testing demands.

References

1. Wikipedia. Drug testing overview.
2. SAMHSA. Mandatory drug testing guidelines.