High-Throughput Screening of Drugs in Hair with Shimadzu MS

Introduction

Since the hair root is vascularized during its growth, illicit drugs present in the blood stream may enter the hair shaft via the root where they will be sequestered. Therefore, the use of illicit drugs can be revealed by analyzing a small hair sample. To increase the analysis throughput of hair samples, the Luxon Ion Source^® coupled to tandem mass spectrometry (MS/MS) was used for the identification and quantification of drugs of abuse.

Our goal for this application note is to use an automated sample preparation method for the screen of drugs in hair sample using a single operation in LDTD-MS/MS.

LDTD-MS/MS offers specificity combined with an ultra-fast analysis for an unrivaled screening method. To develop this application, we focused on performing a quick and simple sample preparation. Drugs are analyzed simultaneously with quantitative screening results obtained in less than 9 seconds per sample.

Sample Preparation Method

Automated Sample Extraction

• 10 mg of hair cut into small pieces are transferred into barcoded tubes, readable by the Azeo Liquid Handler.
• A pre-wash of the hair is performed to remove external contaminants using 1 mL of Methanol, soak 5 minutes and decanted.
• 1 mL of methanol containing TFA at 0.5% (with internal standard) is added and samples are soaked at 60 degrees Celsius for 1h45. Samples are then sonicated for 15 minutes.
• After the extraction, vials were transferred to the Azeo system.
• Each barcoded vial was scanned by the Azeo Liquid Handler system (Figure 3).
• 20 µL of desorption solution (KH₂PO₄ (0.1 mM) in water) were mixed with 20 µL of sample.
• 8 µL of mixture were deposited onto a 96-LazWell™ plate.
• Samples were evaporated to dryness at 40 degrees Celsius for 5 minutes.
• Luxon-MS/MS analysis is performed after a complete evaporation.

LDTD-MS/MS Parameters

LDTD

Model: Luxon SH-960, Phytronix

Carrier gas: 4.5 L/min (air)

Laser pattern:

• 3-second ramp to 55% power
• Hold 2 seconds at 55% power

MS/MS

MS model: LCMS-8060, Shimadzu

Ionization: APCI

Table 1 – Mass spectrometer transitions (Positive)

Table 2 – Mass spectrometer transitions (Negative)

Results and Discussion

Initial Cut-off Test

Table 3 shows the suggested screening cut-offs currently used in the industry.

Table 3 – Analytes and Cut-offs

=

Desorption peak

Figure 4 shows a typical desorption peak for a blank sample for Cocaine and Figure 5 shows a typical desorption peak for a cut-off sample for Cocaine. Similar results were obtained for the other drugs.

Precision

Spiked samples around the decision point and blank solutions are used to validate the precision of the method. The peak area against the internal standard (IS) ratio was used to normalize the signal. Replicate extractions are deposited on a LazWell™ plate and dried before analysis.

The following acceptance criteria were used:

• Each concentration must not exceed 20% CV.
• Mean concentration ± 2 times the standard deviation must not overlap with other concentrations at the cut-off.

Table 4 shows the precision results at the cut-off level.

Table 4 – Inter-run precision

Conclusion

Luxon Ion Source combined to a Shimadzu LCMS-8060 mass spectrometer system allows ultra-fast (9 seconds per sample) screening of drugs in hair using a simple and automated sample preparation method.