the use of high resolution mass spectrometry and statistical analysis in the investigation of food...
TRANSCRIPT
©2015 Waters Corporation 1
The Use of HRMS and Statistical Analysis in the Investigation of Food Authenticity
Basmati Rice
©2015 Waters Corporation 2
Contents
Overview
Experimental Workflow
Samples and Sample Preparation
Data Collection and Processing
Initial Results
Summary and Conclusions
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Why ?
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For years, Indian traders have been passing off a
lesser quality rice, CSR 30, as the world's finest
long-grained, aromatic rice, Basmati, in key markets
like the US, Canada and the EU. In the process, the
rice exports enjoy the duty exemption accorded to
pure Basmati in the EU, thousands of consumers
get duped both in the domestic and export
markets, and the stock of traditional grain gets
depleted on Indian farms.
Basmati Rice Economic Adulteration
In Britain, the Food Standards Agency found in 2005 that
about half of all basmati rice sold was adulterated with other
strains of long-grain rice, prompting rice importers to sign
up to a code of practice.[8] A 2010 U.K. test on rice supplied
by wholesalers found four out of 15 samples had cheaper
rice mixed with basmati, and one had no basmati at all
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Analysis Workflow
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Analysis Workflow
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Samples and Sample Preparation
10 g dry rice in headspace/SPME vial
3 Replicates of each sample
A pooled composite sample
Randomized sample list
Sample Description Sample ID
1 Basmati Manufacturer 1 BAS M1
2 Basmati Manufacturer 2 BAS M2
3 Long Grain Manufacturer 3 LG M3
4 Basmati Manufacturer 4 BAS M4
5 Jasmine Manufacturer 5 JAS M5
6 Basmati Manufacturer 3 BAS M3
7 Jasmine Manufacturer 4
JAS M4
8 Composite Sample Pool
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Analysis Workflow
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Instrument Conditions: SPME Autosampler
Supelco SPME gray hub notched
Divinylbenzen/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS)
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Instrument Conditions: GC
Column: 30 m DB-5
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Analysis Workflow
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Universal Source Technology …High Performance and simplicity of operation
IonKey Source
with nanoTile Technology.
Plug & Play nanoFlow
APGC – Atmospheric Pressure
Gas Chromatography
ASAP – Atmospheric Pressure
Solids Analysis Probe
MALDI nanoFlow ESI APCi ESCi APPI TRIZAIC ASAP APGC
Wide Range of Ionization Options
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Instrumentation Setup
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Mass Analyser GC Oven
N2 make-up gas delivered through transfer line interior
N2 meets GC eluent flow at transfer line tip
With thanks to Paul Silcock
APGC – How it works
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Comparison of EI vs APGC spectrum of Chlorfenapyr
MSE Low energy
MSE High energy
EI Library spectrum
APGC spectrum
C15H11BrClF3N2O
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Instrument Conditions:
SYNAPT G2-Si
Source Conditions
HDMSE Acquisition Mode
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MSE
Fragmentation in Trap or
transfer
Alternate Low and High
Energy Scans
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MSE – no mobility separation
Imazalil from an EU Mandarin PT Sample
Low Energy
High Energy
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Fragmentation in Transfer
Mobility separation
Alternate Low and High Energy Scans
precursors and products have same drift
time
HDMSE
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Transfer Fragmentation
Drift time
Precursor ions
m/z
Precursor and products are time aligned
Drift time
m/z
Precursor ions
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IMS
-9 -8 -7 -6
TOF MS LC
-5 -4 -3 -2 -1 0 1 2 3 4 n 10n seconds
Ion Mobility: an Orthogonal Dimension of Separation
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HDMSE – MSE with a mobility separation
Low Energy
High Energy
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Analysis Workflow
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Progenesis QI - Workflow
Alignment
Peak Detection
Component Intensity
Comparison
Identification
Statistics
Deconvolution
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Initial Results: PCA
Basmati ?
Jasmine ?
Long Grain ?
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PCA to S Plot
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S Plot
Common Markers
Markers prominent in Long Grain
Marker Importance
Mark
er
Confidence
Markers prominent in Basmati
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Markers of Interest
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Correlation Analysis
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Correlation Analysis: Basmati Markers
Prominent markers in basmati
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Correlation Analysis: Long Grain Markers
Prominent markers in long grain
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Finding Markers of Interest
So, what now?
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Elucidation
Elucidation by:
— Elemental Composition
— Integrated Chemspider Search
— Fragment Match
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Elucidation
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Elucidation
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Elucidation
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Elucidation
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Elucidation
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Progenesis QI Database Search
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Progenesis QI Database Search
The components of interest can be searched
against a number of user customizable
databases
A list of potential identifications is generated
and scored using mass accuracy, isotope
distribution, retention time, drift time and
fragmentation
If the data base contains structures theoretical
fragmentation is performed and a fragmentation
score is used to rank the potential identifications
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Progenesis QI Database Search
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Progenesis QI Database Search
HDMSE
MSE
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Further Database Search Results
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Further Database Search Results
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Further Database Search Results
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Further Database Search Results
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Finding Markers of Interest
X
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Waters “Omics” Research Platform Solutions with Progenesis QI Informatics
Proteomics
Metabolomics Lipidomics
Authenticity
Plant/Food Profiling
Plant Metabolomics
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Research to Routine
Xevo G2-S Q-ToF SYNAPT G2-Si HDMS
X
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Summary of Key Information Points
Identification: Elucidation or via database search. Drift and
time aligned HDMSE data facilitates the process.
Isolation: Progenesis QI alignment and peak picking
algorithms ensure markers of all intensities are correctly
tracked across all samples.
The principle behind the experiments has remained the same.
These advancements in hardware and informatics are
reducing the size of the task
Detection: HDMSE acquisition: High Specificity, enhanced
peak capacity over standard MSE acquisition.
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So What Now for Basmati Rice?
Method development and proof principle using off the shelf samples.
Now require a collaborator with access to well characterised samples
that are known pure/adulterated/spiked/suspect.
Investigate the use of relevant available databases for facile marker
searching.
Ideal situation is to get from research to quality control.
The principle of detection, isolation and identification can be used for
other applications
— Contamination investigation
— Good tasting product vs bad
— Food packaging leachables extractables
— Food Metabolomics
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Questions ?