Benchmarking and Publications for
Non-Targeted Analysis Working Group
(BP4NTA)
Co-Chairs:
Ben Place (NIST, Gaithersburg, MD)
Elin Ulrich (US EPA, RTP, NC)
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Mention of product or trade names does not indicate endorsement.
The views expressed in this presentation are those of the author(s) and do not necessarily represent the views or policies of the U.S. Government.

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ENTACT Workshop (August 2018)
•	The EPA's Non-Targeted Collaborative Trial (ENTACT) was an
interlaboratory comparison of nontargeted analytical methods with
nearly 30 participants (DOI: https://doi.org/10.1007/s00216-018-
•	In August 2018, the US EPA held a workshop with ENTACT participants
(and other NTA practitioners) in RTP.
•	During the workshop, smaller discussion groups were formed with
specific topics of interest.
• Two different groups (Benchmarking/Proficiency Testing and
Publications/Peer Review Standards groups) were merged together based on
mutually-shared interests.

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BP4NTA Working Group
•	The perspective of the group at the workshop was: the NTA
community, peer-reviewers, and journal editors need to use a
common language when reporting NTA methods and results.
•	Shared terms and definitions can lead to better comparison of methods and
results.
•	We can determine benchmark performance only once methods and results
reporting are more harmonized.
•	Once benchmarks set, can then tackle concepts like "proficiency testing" for
NTA measurements.
•	Formed the Benchmarking and Publications for Non-Targeted Analysis
(BP4NTA) Working Group.

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Working Group Members
•	Currently, the working group is ~80
international members.
•	Membership based on interest in NTA.
•	Wide range of experience with NTA, from
relative beginners to experts.
•	Primarily focused on environmental/
exposure non-targeted analysis.
•	Some members represent food analysis
and metabolomics.
•	Focused on exogenous chemicals, and
usually from a bottom-up (source)
perspective.
Membership of BP4NTA

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Working Group Operation
•	Monthly phone calls.
•	Use of Google Drive to create collaborative documents and post
useful information for the group.
•	Currently not affiliated with a larger organization, but are
investigating that option.
•	Nine subgroups (N = 5-10) have taken on the bulk of current efforts.

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Short-Term Working Group Objective
•	Create a list of commonly-used NTA terms, concepts, and
performance calculation and provide definitions/equations.
•	Publish guidance document that shares these terms, based on community
consensus and feedback.
•	Audience broad, including new NTA researchers, journal reviewers/editors,
and expert users.
•	Reporting recommendations and scientific best practices to promote
transparency and reproducibility.
•	Further dialogue with journal editors to encourage the use of reporting
recommendations as related to the defined terms.

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Long-Term Working Group Objective
•	Move the field of NTA toward proficiency testing, using a mechanism
like ASTM/ISO Guidance on Performance and Data Reporting
Requirements. Define proficiency levels for SSA, NTA, expert,
competent, etc. This is likely 10 years out.
•	Build and maintain coalitions/communications with other groups that
have similar interests including metabolomics, NORMAN, mQACC.

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Consensus-building process
Terms that Need
to be Defined
Identification/
Confidence of
Identification
Non-Targeted
Analysis / Suspect
Screening
False Positive /True
Positive / False
Negative
Data Analysis
Method
Library / Database
Matrix Blank / Spike
/ Standard /
Replicate
Instrumental
Method
Performance / Accuracy /
Reproducibility / Precision
Sample
Preparation
Draft Document
Draft Consensus
Document
Consensus
Document
We are here (in revision)

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Examples of definitions-
Confidence of Identification/Identification
Annotation
Attribution of one or more compound-
identifying properties to a detected
feature. These properties may not
provide enough evidence to identify a
single compound.
Identification
The case where the annotated
compound-identifying properties
provide enough evidence to attribute a
specific compound within a stated
scope to the measured feature
Confidence of
Identification
/Annotation
The data evidence and/or statistical
foundation that supports the proposed
identification. The determination of
confidence should be presented in a
clear and concise fashion.
"Schymanski scale"
Chemical Formula Chemice
Structural Information
1 c|ass Fragment / Neutral Loss
chemical Formula Annotation
Collisional cross section
\ \
/ /
Single Con
(with st
Identification
ipound Identity
ated scope)
Example
Identification confidence
Level 1: Confirmed structure
by reference standard
Level 2: Probable structure
a)	by library spectrum match
b)	by diagnostic evidence
{l
Level 3: Tentative candidate(s)
structure, substituent, class
Minimum data requirements
MS, MS2, RT, Reference Std,
MS, MS2, Library MS2
MS, MS2, Exp. data
MS, MS2, Exp. data
L^n-C Level 4: Unequivocal molecular formula MS isotope/adduct
https://doi.org/10.1021/es50021Q5	"C tg"g/5:	of interest
MS

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Examples of definitions- Instrumental Method
• Instrumental methods comprise a detailed list of conditions and parameters that are
set or used for the acquisition of (high resolution) mass spectrometry raw data files
(to include separations) used in suspect screening and/or non-targeted analysis.
Settings, conditions, and parameters generally fall into broad categories including but
not limited to: instrument, chromatography column(s), mobile phase, injection,
sample, ion mobility, mass spectrometry (general and specific), tuning/mass
calibration, and lock/reference mass.
LC
GC
Location in publication
Column manufacturer, part#, lot#
Column manufacturer, part#, lot#
Main
Stationary phase
Stationary phase
Supplemental
Length
Length
Main
Particle size
Film thickness
Main
Pore size

Supplemental
ID
ID
Main
Column startup, conditioning, shutdown method

Supplemental
Guard column and dimensions
Retention gap/pre-column and dimensions
Main

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Path forward
•	Decide on format and outlet for draft document(s). Thoughts?
•	Complete draft document for community review. Publish.
•	Reach out to other NTA working groups/consortia that have similar
goals and objectives.
• Identify ways to collaborate and complement efforts.
•	Reach out to journal editors to start conversation on creating
reporting standards for NTA research.

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