by

Scott R. Oulton, SWGDRUG Secretariat

Scientific Working Group for the Analysis of Seized Drugs Update

OVERVIEW In January 2010, the core committee

approved two documents: 1) Supplemental Document SD-3 For Part IVC –

Examples of Measurement Uncertainty for Weight Determinations

2) SWGDRUG Recommendations 5th Edition (revised/edited current recommendations)

Current work projects and future topics Four active subcommittees (uncertainty, editorial,

education and training and CLIC collaboration) Proposed change to reporting requirements New initiatives

Supplemental Document SD-3 for Part IVC

“Examples of Measurement Uncertainty for Weight Determinations”

SUPPLEMENTAL DOCUMENTSSupplemental Documents

Intended to be a resource for those implementing recommendations

Not all inclusive, many ways to implement recommendations

Purpose is to provide examples to be used in conjunction with SWGDRUG Recommendations

The draft supplemental document was posted for public comment in July 2009

Many comments were received The document was vetted through

professional metrologists and statisticians Supplemental Document SD-3 was adopted

January and posted in July 2010

UNCERTAINTY SUBCOMMITTEE

Type A – statistically determined from repetitive measurements (e.g., control chart)

Type B – everything else (e.g., calibration report) Three examples were developed

Example 1: 1 bag of powder (type B uncertainties) Example 2: 1 bag of powder (type A -B uncertainties) Example 3: 15 bags of powder (type A -B uncertainties)

In Example 1, five significant uncertainty sources were considered. For example 2 & 3, data from a well-established control chart captures three of these factors

SUPPLEMENTAL DOCUMENT SD-3

Multiple approaches exist for estimating uncertainties Elements used contain correlated and uncorrelated

sources The illustrated methods in these examples

represent a conservative approach in which the uncertainty is likely to be overestimated This is done to conservatively account for all

correlations even those that for all practical purposes cannot be determined

SUPPLEMENTAL DOCUMENT SD-3

Readability Repeatability Linearity Buoyancy (insignificant) Sensitivity (insignificant) Uncertainty from balance calibration Number of weighing events Sample loss in transfer: for practical

purposes, this is considered indeterminate and irrelevant

FACTORS CONSIDERED

Determine net weight of a white powder received in a plastic bag using a top loading balance. The following conditions apply: The operator is competent on the use of the

balance The balance is:

o calibrated and certifiedo being used above the established minimum

balance loado performing within manufacturer specificationso located in a temperature-controlled

environment (±5 °C)

EXAMPLE SCENARIO

A weigh vessel is: loaded and tared removed and filled with powder reweighed containing powder

Net weight = 30.03 grams Static weighing – obtaining net weight via two

weighing operations Two weighing events

Dynamic weighing – adding powder directly to tared vessel on balance One weighing event

EXAMPLE SCENARIO

Expanded Uncertainty U = k * uc

Using Coverage Factor (k) = 2 (approx. 95%)U = 2 * 0.0176 g = 0.0352 g

Final Ufinal = U * # weighing eventsUfinal = 0.0352 g * 2 = 0.0704 g

CALCULATION2222 )()()()( calbalulinearurepeatureaduuc

guc 0176.00065.00115.001.000577.0 2222

ResultsNet Weight: 30.03 g ± 0.07 g (k=2)Net Weight: 30.03 g ± 0.11 g (k=3)

RESULTS

Uncertainty estimates associated with quantitative measurements e.g., 82.4% ± 3.2%

Extrapolations of weights Weight determined by statistically

measuring a set amount of sub itemso e.g., 10 out of 500 bricks of cocaine

weighed and extrapolated to calculate total weight of 500 kg. The uncertainty is estimated based on statistical analysis of 10 weighed units

WHAT NEXT?

SWGDRUG Recommendations5th Edition

Goal – Revision of existing SWGDRUG Recommendations to:Harmonize terminologyCorrect grammarAdd referencesLink sectionsCorrect sections in conflictClarify recommendations as appropriateUpdate glossary

EDITORIAL COMMITTEE

§ 2 Education and experience for analysts Before:

oa bachelor’s degree (or equivalent, generally a three to four year post-secondary or tertiary degree) in a natural science or in other sciences relevant to the analysis of seized drugs…

OR oby January 1, 2005, a minimum of five (5)

years practical experience in the area of seized drug analysis…

SIGNIFICANT CHANGES

§ 2 Education and experience for analysts After:

oAll new analysts shall have at least a bachelor’s degree (or equivalent, generally a three to four year post-secondary degree) in a natural/physical science.

SIGNIFICANT CHANGES

§ 3 Continuing professional development Before:

o Contact is defined as face-to-face interaction with an instructor or trainer in a classroom or laboratory setting. It does not include self-paced learning or distance education where the instructor has no active interaction with the student.

After:o 3.4 Training can be either face-to-face interaction

with an instructor, distance learning, self-directed or computer based.

Added: current literature review

SIGNIFICANT CHANGES

§ 11 Analytical method validation and verification Before:

o 11.1 Method validation is required to demonstrate that methods are suitable for their intended purpose.

11.1.1 For qualitative analysis, the parameters that need to be checked are selectivity, limit of detection and reproducibility.

11.1.2 Minimum acceptability criteria should be described along with means for demonstrating compliance.

11.1.3 Validation documentation is required. o 11.2 Laboratories adopting methods validated elsewhere should verify these methods

and establish their own limits of detection and reproducibility. After:

o Method validation is required to demonstrate that methods are suitable for their intended purpose (see PART IV B – Validation).

SIGNIFICANT CHANGES

Added hyperlinks to Uncertainty section throughout document

Added hyperlinks to Validation section throughout document

Added “Shall” in place of “Should” in several locations (conduct, ethics, education, etc.)

SIGNIFICANT CHANGES

Revisions to Glossary: Added definition for “false negative” Updated several definitions as a result of

some ISO terms amended within the last few years

e.g., ISO 3534-2:2006, VIM 2008Category A now includes: X-Ray

Diffractometry

SIGNIFICANT CHANGES

Before§ 3.1 … Use second technique …§ 3.1.2 When sample size allows, the second

technique should be applied on a separate sampling for quality assurance reasons. When sample size is limited, additional measures should be taken to assure that the results correspond to the correct sample.

§ 3.4 In cases where hyphenated techniques are used (e.g. gas chromatography-mass spectrometry, liquid chromatography-diode array ultraviolet spectroscopy), they will be considered as separate techniques provided that the results from each are used.

SIGNIFICANT CHANGES

Problem If two samplings important, why have

different procedure for trace samples? Misinterpretation of 3.4, hyphenated

techniques do not offer second samplingSolution

Revise section to emphasize quality assurance stepo Second samplingo Procedural blanko Witnessing

SIGNIFICANT CHANGES

After The laboratory shall employ quality

assurance measures to ensure the results correspond to the exhibit. Example measures are:o the use of two separate samplings o sample identification procedures such as bar-

coding and witness checkso good laboratory practices (e.g., positive and

negative controls, one sample opened at a time, procedural blanks)

SIGNIFICANT CHANGES

Problem e.g., Is DART a Category A or B?

Solution Techniques for the analysis of drug samples

are classified into three categories based on their maximum potential discriminating power. However, the classification of a technique may be lower, if the sample, analyte or mode of operation diminishes its discriminating power.

SIGNIFICANT CHANGES

Solution Examples of diminished

discriminating power may include:oan infrared spectroscopy

technique applied to a mixture which produces a combined spectrum

oa mass spectrometry technique which only produces molecular weight information

SIGNIFICANT CHANGES

Education and Training Subcommittee

Phase 1 Develop core competencies (outline form) Coordinate efforts with ENFSI Drugs Working

Group Phase 2

Identify existing resources (open source, for purchase, etc.)

Phase 3 Post example training programs on-line

EDUCATION AND TRAINING SUBCOMMITTEE

Proposed Revision toReporting Requirements

Mirror ISO/IEC-17025 LanguageNASTransparency

Why Change Reporting?

9.2 Report writing Reports issued by laboratories shall be accurate, clear, objective, and meet the requirements of the jurisdictions served. Unless the laboratory has reasons for not doing so, these reports shall include the following information:

title of report identity and location of the testing laboratory unique case identifier (on each page) clear identification of the end of the report submitting agency date of receipt date of report descriptive list of submitted evidence identity and signature (or electronic equivalent) of analyst results / conclusions analytical techniques employed sampling uncertainty.

Report Writing

116 Responses For – 38% Against – 62%

Most commons reasons against proposal Analytical Techniques Sampling Uncertainty

Cited reasons Courts would not understand Defense attorneys would have a field day Would have to testify more

Survey Results

Analytical Techniques Presumptive test only, qualitative determination

Sampling Tested 1 unit, report all containing

Uncertainty Enhances confidence through increased

understanding of resultso e.g., Gas pump accuracy for 10 gallons

Gas Station 1: 10 ± 0.03 galGas Station 2: 10 ± 1.35 gal

Near statutory thresholdo Blood alcohol 0.08

Survey Results

SWGDRUG9.2 Report writing Reports issued by laboratories shall be accurate, clear, objective, and meet the requirements of the jurisdictions served. Unless the laboratory has reasons for not doing so, these reports shall include the following information:

ISO 170255.10.2 Each test report or calibration certificate shall include atleast the following information, unless the laboratory has validreasons for not doing so:

Survey Results

New Initiatives

Formal Survey Assess implementation of recommendations

in the forensic science community Using www.surveymonkey.com

MS Database Contains over 1200 compounds Inviting community to participate

Cooperation with CLIC Developing recommendations for analysis of

clandestine laboratory samples Development of uncertainty spreadsheet

New Initiatives

SWGDRUG Core Committee

CORE COMMITTEE• DEA – Scott Oulton (Chair)

• Secretariat – Sandra Rodriguez-Cruz

• FBI - Eileen Waninger• ASCLD – Garth Glassburg• NIST – Susan Ballou• ASTM and NEAFS – Jack Mario

• Educator – Vacant (Eric Person)

• Educator – Dr. Suzanne Bell

CORE COMMITTEE• CAC & NWAFS – Jerry Massetti

• MAFS – Richard Paulas• MAAFS – Linda Jackson• SAFS – Christian Matchett• SWAFS – Scott Vajdos• Toxicology – Dr. Robert Powers

CORE COMMITTEE

• Canada – Richard Laing• Japan – Osamu Ohtsuru• United Kingdom – Dr. Sylvia Burns

• Australia – Catherine Quinn• Germany – Dr. Udo Zerell• ENFSI – Dr. Michael Bovens• UNODC – Dr. Iphigenia Naidis

Visit us at:www.swgdrug.org