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Chetan Shende, Frank E. Inscore, Atanu Sengupta, Hermes Huang and Stuart Farquharson

www.rta.biz

chetan@rta.biz

Rapid Detection and Identification of Overdose Drugs in Saliva by Surface-Enhanced Raman Spectroscopy

Funding:

UK Road Policing TechnologiesHome Office Scientific Development

Branch

NIH and NSF

Screening Abused Drugs in Salivaat Road-Side & Emergency-Roomfor Driver Impairment & Overdose

Pittcon 2012RTA Booth #2110

Challenge: Drugs in salivaNational Highway Traffic Safety Administration Stats:2007: 11% of drivers stopped tested positive for drugs2009: 18% of driver fatalities tested positive for drugs

The analyzer must typically provide the following:

• Specificity – Identify and discriminate drugs (No False Positives!)

• Sensitivity – Detect ~10-8 M or less (10-50 ppb)

• Reproducibility – Accurate and Repeatable (No False Negatives!)

• Speed – Analysis within 10 minutes

• Field Usable – Battery Operated and Rugged

The Solution: SERS

Specificity: Every chemical produces a unique Raman spectrum allowing unequivocal identification.

Sensitivity: Silver and gold nanoparticles increase Raman signals by 1 million times or more allowing 10-8M (ppb) detection.

CH3N

CO2CH3

O2C

H Cl -

Cocaine Hydrochloride

+

SERS: 100 ppb Cocaine

Raman: Pure Cocaine

Gold Sol-Gel SERS Capillary

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RTA’s SERSID - Trace Chemical Analyzer

Patents: 6623977, 6943031, 6943032, 7312088, 7393691, 7393692, 7462492, 7462493, 7713914

2010

UK Road-Side Screening: Required Drugs

35 drugs & metabolites were measured31 active on gold, 4 (barbiturates) active on silver

Spectra search worked for all drugs Providing Chemical Information When & Where You Need It

The Proposed Device

The proposed SERS-RSSD-DD (Road Side Screening Device for Drug Detection) will extract, identify, and quantify the presence of drugs (and

metabolites) in driver saliva at ~10-8M within 8-10 minutes.6

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SERS of Representative Illicit, Prescription & OTC Drugs in Expanded Gold Spectral Library (150)

PCP

Methamphetamine

MDMA

LSD

Heroin

Diazepam

Ritalin

Demerol

Hydrocodone

Oxycodone

Acetaminophen

Acetylsalicylic acid

Ibuprofen

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Library Search: Measure Priority DrugsSpectra search and identification works for all drugs

Hit Quality Name1 0.001 Nordiazepam2 0.010 Methadone3 0.010 Oxazepam4 0.010 Temazepam5 0.012 Norcodeine

Hit Quality Name1 0.036 Nordiazepam2 0.357 Temazepam3 0.363 Diazepam4 0.373 Methadone5 0.392 Oxazepam

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Cocaine: Static Concentration Data

50 ppb Cocaine

Background from glass capillaryIt can be subtracted.

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25 ppb = 7x10-8M

Sensitivity: Static ROC Curves of Cocaine

50 ppb

25 ppb

• ROC = establish threshold that signal can be detected above noise. • K value = statistically significant separation between true & false response.• K > 3.29 used by US Army for 95% probability of detection.• Sensitivity = 48 ppb. Indicates that Cocaine SERS peaks can be

positively detected above noise 95% of the time at 48 ppb and higher.

100 ppb

75 ppb

50 ppb

25 ppb

0 ppb

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Developed Saliva Extraction Method

1. Collect 0.5 ml in 1 min 2. Expel sample into buffer 3. Filter sample

4. Draw sample into microSPE 5. Elute cocaine from SPE 6. Inject sample in SERS Capillary

7. Measure spectrum

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Capillary microSPE used for extraction

50 ppb Drug in Saliva Samples

Extracted from 0.5 mL saliva & detected in 10-minutes!!

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Hit Quality Name1 0.236 Cocaine

1 0.171 Diazepam

1 0.171 PCP

1 0.066 Methadone

Cocaine 50ppb

Diazepam 50ppb

PCP 50ppb

Methadone 50ppb

Cocaine Extracted from SalivaSaliva ROC Curve: A) 75, B) 50, C) 25 ppb

Probability of detection is 66% at 25 ppb, 92 % at 50ppb and 100% at 75 ppb, at 95% confidence level.

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R&D: SERS Lab-On-Chip

Different Lab-on-Chip designs used

Preliminary LOC Results: in Saliva at 50 ppb

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amphetamine 50ppb

cocaine 50ppb

diazepam 50ppb

PCP 50ppb

methadone 50ppb

All Drugs Correctly Identified by Spectral Match!

Library reference

Actual Saliva Measurements: UK Tests

Results:Spectra of samples measured

by UK personnel

Note: Cocaine, Methamphetamine, & PCP

spectra are very similar, but sufficiently different to be identified.

50 ppb Cocaine

1 ppm PCP

100 ppb Cocaine

In Water

In Saliva

100 ppb Metham-phetamine

50 ppb PCP

In Saliva

50 ppb PCP

Male Saliva

Female Saliva

Real Clinical Saliva Samples

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Chronic user, male #1

All Samples Correctly Identified by Spectral Match!

Casual user, female

Sample collected 30 minutes after use

5 hours after usemale #2

150 Drugs in Expanded Gold SERS Library:

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• Non-Invasive: Cotton Swab• Field Portable: 7 pound Raman analyzer• Small Sample Volume: < 1 mL• Rapid & Simple Analysis: 10 minutes (total)• Specificity: similar drugs can be differentiated• Generality: over 250 drugs measured • Sensitivity: measured < 50 ppb in saliva

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Summary: saliva drug analysis

References:1) Detection of Drugs of Abuse in Saliva by Surface-enhanced Raman

spectroscopy. Applied Spectroscopy, 65, 9 (2011). 2) Rapid Detection and Identification of Overdose Drugs in Saliva by Surface-

enhanced Raman Scattering Using Fused Gold Colloids. Pharmaceutics, 3,425-439 (2011).