Rapid Detection of Chemical Contaminants New Frontiers in Food - - PowerPoint PPT Presentation

Rapid Detection of Chemical Contaminants

Synergising Food Safety, Quality and Regulatory Dimension for Excellence in Food Ecosystem

• Dr. Anoop A. Krishnan

Assistant Director Export Inspection Council

New Frontiers in Food analysis

Introduction

DILUTE AND SHOOT

Introduction

❖ The contamination of food by chemical hazards is a worldwide public health concern and is a leading cause of trade problems internationally. ❖ Chemical contaminants may occur in our food from various sources. They typically pose a health concern, resulting in strict regulations of their levels by national governments and internationally by the Codex Alimentarius Commission. ❖ Analysis of relevant chemical contaminants is an essential part of food safety testing programs to ensure consumer safety and compliance with regulatory limits. ❖ Modern analytical techniques can determine known chemical contaminants in complex food matrices at very low concentration levels. Moreover, they can also help discover and identify new or unexpected chemical contaminants.

Introduction

• In recent years,

hyphenated techniques have received ever- increasing attention as the principal means to solve complex analytical problems. The power

• f

combining separation technologies with spectroscopic techniques has been demonstrated

• ver the years for both quantitative and qualitative analysis of

unknown compounds in complex natural product extracts or fractions.

• To obtain structural information leading to the identification of the

compounds/speciation forms present in a crude sample resulted in the introduction of various modern hyphenated techniques, e.g., CE-MS, GC-MS, LC-MS, LC-ICPMS and LC-NMR.

Chemical contaminant-Sources

Chemical contaminants can be present in foods mainly as a result of the use of ✓ Agrochemicals, such as residues of pesticides and veterinary drugs ✓ Environmental Contaminants- Heavy metal, Dioxins etc. ✓ Food processing Contaminants- Nitrosamines, PAH etc. ✓ Migration from food packaging materials- Phthalates etc. ✓ Toxins- Mycotoxins, marine bio toxins etc. ✓ Unapproved food additives and adulterants- melamine, Sudan dyes etc.

Cob web of Food safety

Evolution of analytical methodology

Ref: Modified from Seiber, J. N.,Regulation of Agrochemicals, American Chemical Society, Washington, D.C., 1991.

Technical innovation in Instrumentation

• The evolution of the analytical instrumentation used by

various laboratories in the last seven years has drastically changed and new technical innovation and evolution have

• come. The use of conventional detectors has decreased, giving

way to triple quadrupoles, which are, without question, the most widely used instruments for both gas and liquid

• chromatography. In GC, single quadrupoles and ion traps

have been replaced by triple quadrupoles (LCMSMS/GCQQQ)

• During

the last years the introduction

• f

liquid chromatography high resolution mass spectrometry (LC- HRMS) has become popular in pesticide residues

• laboratories. The advantages in getting exact mass of the

analytes have been evaluated giving an important and new solution to common problems of these analyses.. Recently new GC-HRMS are intending to cover a similar position for typical GC pesticide residues.

Whatever is there, find it!

Sample Preparation (extraction, cleanup, concentration, digestion) Instrumental Analysis Data Processing Sample Processing/Homogenization The techniques employed here decide if the overall method is

• Multi-Residue,
• Single-Residue
• Group-Specific

Interdependence of Analytical steps

Sample preparation is critical, any losses here... cannot be recovered afterwards! All instrumental analysis techniques available have some inherent limitations in terms of … Sensitivity, Selectivity, Robustness (matrix tolerance) “Thus, sample preparation and instrumental analysis always have to be observed together” Sampling

Analysis of food contaminants

➢ One

• f

the current trends in analytical chemistry is the method development for many

• ptimized

tools used in classical methods. ➢ The basic analytical approach involves an extraction using a suitable solvent/digestion using acids, clean up to remove interfering matrix components, a chromatographic separation and a selective detection. ➢ It is not an exaggeration to say that the implementation of mass spectrometry (MS) as a detection technique has truly revolutionized the analysis

• f

chemical contaminants in foods.

Analysis of food contaminants

➢ As opposed to element-selective or non selective detectors, MS can detect a wide range

• f

compounds independent

• f

their elemental composition and provide simultaneous quantitation and structural identification

• f

detected analytes. ➢ Fast analysis, consumption of small amounts of samples and reagents, high sensitivity and automation are some of the most important goals desired to be achieved. ➢ More generic Multiresidue, Multiclass analysis methodologies with high sensitivity and expanded scopes, which include as many compounds and commodities as possible in a single method are being developed

Analytical Approach

➢ Whether a method is single or multiresidue in scope, it will include a series of discrete steps or unit processes whose ultimate goal is to detect and quantify specific chemicals at levels of interest, in a relatively complex food matrix. ➢ The matrix may contain hundreds or even thousands of natural and man-made chemicals which can potentially interfere with the analyte(s) of interest, often at concentrations many-fold higher than those of the analytes. It is a proverbial “needle in the haystack” undertaking. ➢ Thus, methods must be designed to take advantage of unique physical properties, such as polarity, volatility, and

• ptical

properties, and chemical properties (reactivity, complex formation, combustion characteristics) which allow the analyte to stand out from the forest of matrix-derived interferences.

Analytical Approach

• Extraction: Remove the analyte from the matrix, leaving the bulk of

the matrix behind as a filterable or non volatile mass.

• Clean up: Remove unwanted coextractives by such operations as

column chromatography, liquid-liquid partitioning, volatilization,

• r chemical degradation.
• Modification: Convert the target analyte to a derivative which is

more readily separated, detected, or quantitatively determined than the parent. Modification may be done pre- or post-cleanup, or after the resolution step in operations such as post-column derivitization.

• Resolution: Separate the analyte from remaining interferences,

usually by some form of refined chromatography

Analytical Approach

• Detection — Obtain a response related to the amount of analyte
• present. Chromatographic detectors, spectrophotometers, and mass

spectrometers are the mainstays for achieving this objective, although immunosorbent-based methods are coming into more common use.

• Measurement — Relate the response of the analyte to some known

standard, of the analyte itself or a surrogate with similar properties, for calculating the concentration in the original matrix.

• Confirmation — Provide assurance that the primary method gives

correct (i.e., accurate and precise) results, by use of a second, independent method. This has become much more important in recent years due to the emphasis on quality assurance/quality control (QA/QC) in the analytical laboratory.

Testing kits: immunoassay

From http://www.horiba.com

• Preliminary screening for particular known compounds
• Advantage: low cost, speed and ease of use
• Limitation: individual or small group of compounds only

High Selectivity in Instrumental Analysis gives more flexibility in sample preparation GC/LC analysis

QuPPe, MiniLuke QuEChERS, Ethylacetate (SWET) Microwave digestion MIPs/Immunoaffinity Column chromatography Solid Phase Extraction Dispersive SPE Selective extraction solvent Generic extraction solvent

GC-FID GC-ECD GC-NPD/AAS GC-FPD/Ultra HPLC/ICP-OES GC-MS (quad/TOF)/LCMSMS/LC-TOF GCxGC-MS, GC-MS/MS, GC-hrMS, LC-hrMS GCxGC-hrMS, GC-QTOF, IRMS, APGC, Traps Orbitrap/MS, MALDI-TOFMS, HPLC-ICPMS

Sample preparation Increasing selectivity  Increasing selectivity Power to discriminate: Isomers Metabolites Megradation products Matrix components Endogenous compounds

New Frontiers in Food Analysis

Recoveries • Safe • Speed/Time • Clean-up efficiency • Cost

SPE dSPE Effective clean up Easy of Use/Efficiancy (time)

New Frontiers in Food Analysis

New Frontiers in inorganic analysis

ICP-OES ASV AAS- Flame Fast Sequential AAS LC/IC-ICPMS ICP-MS AAS-Furnace Hydride

Detection limits High (mg/kg) Low (µg/kg)

High Number of elements Low

Analytical requirements

Analytical Interlink

Check that Method Works Check that Method is reliable Check that Laboratory can use it Performance measurement Validation Proficiency Testing Combination should be fit-for-purpose

Challenges

✓ Need for fast, reliable, harmonised multimethods for analysis of a range of contaminants and unknowns ✓ Food fraud = Global issue

Conclusion

➢ It has to be assured that the analytical methods used by official food control laboratories produce reliable results. ➢ Clearly, there has been a tradeoff in terms of investment and cost, such that a modern analytical laboratory must have an array of highly sophisticated and expensive instruments, and of equally sophisticated trained personnel to maintain, run, and interpret the results of the instruments. ➢ The need for more and better analytical data will continue to stimulate developments in analytical chemistry applied to foods. ➢ Safer food, through rapid and cost-efficient tests for detecting chemical contaminants in food is the need of the hour.

From: Fear To: Confidence

Conclusion

Thank you for your kind attention