Trace Detection of Paraquat in Tea Leaves
Applications | 2020 | MetrohmInstrumentation
Paraquat is a potent herbicide widely used to control weeds but associated with significant human toxicity and fatalities. Residual paraquat in tea leaves poses a health risk to consumers, making sensitive on-site detection essential for food safety and regulatory compliance.
The primary goal was to develop a rapid, portable method for trace detection of paraquat residues in tea leaves using a Surface Enhanced Raman Spectroscopy (SERS) analyzer. Key objectives included creating a reference spectral library, determining detection limits, and validating a simplified field protocol for non-expert users.
Tea samples were spiked with known paraquat concentrations, dried at 80 °C, and extracted with chloroform. The extract was mixed with gold nanoparticle solution and sodium chloride to enhance Raman signals. Measurements were performed on-site using a portable SERS analyzer.
Key experimental settings included a laser power of 5 units, 1 s integration time, and ten averaged scans with orbital raster scanning enabled.
The SERS method achieved detection down to 1 ng/g of paraquat in tea leaves. Baseline-corrected spectra displayed characteristic paraquat peaks, confirming sensitivity well below typical regulatory thresholds. A streamlined field protocol using disposable vials and pipettes enabled reliable on-site screening by non-specialists in under 20 minutes.
Advancements in portable SERS technology are expected to enable multiplex detection of various contaminants. Integration with cloud-based platforms and improved nanoparticle substrates may further enhance sensitivity, data sharing, and real-time monitoring across supply chains.
The portable SERS approach offers a fast, sensitive, and field-deployable solution for detection of trace paraquat in tea leaves. Its simplicity and low detection limits support enhanced consumer safety and regulatory compliance.
AN-RS-025 Application Note, Metrohm AG
RAMAN Spectroscopy
IndustriesFood & Agriculture
ManufacturerMetrohm
Summary
Importance of the Topic
Paraquat is a potent herbicide widely used to control weeds but associated with significant human toxicity and fatalities. Residual paraquat in tea leaves poses a health risk to consumers, making sensitive on-site detection essential for food safety and regulatory compliance.
Objectives and Study Overview
The primary goal was to develop a rapid, portable method for trace detection of paraquat residues in tea leaves using a Surface Enhanced Raman Spectroscopy (SERS) analyzer. Key objectives included creating a reference spectral library, determining detection limits, and validating a simplified field protocol for non-expert users.
Methodology and Instrumentation
Tea samples were spiked with known paraquat concentrations, dried at 80 °C, and extracted with chloroform. The extract was mixed with gold nanoparticle solution and sodium chloride to enhance Raman signals. Measurements were performed on-site using a portable SERS analyzer.
Used Instrumentation
- Metrohm Instant SERS Analyzer (MISA Advanced)
- MISA Vial Attachment
- ID Kit with gold nanoparticles (Au NP)
- Chloroform and sodium chloride reagents
Key experimental settings included a laser power of 5 units, 1 s integration time, and ten averaged scans with orbital raster scanning enabled.
Main Results and Discussion
The SERS method achieved detection down to 1 ng/g of paraquat in tea leaves. Baseline-corrected spectra displayed characteristic paraquat peaks, confirming sensitivity well below typical regulatory thresholds. A streamlined field protocol using disposable vials and pipettes enabled reliable on-site screening by non-specialists in under 20 minutes.
Benefits and Practical Applications
- Portable, user-friendly system for rapid contaminant screening
- Trace-level sensitivity suitable for quality control in tea production
- Minimal sample preparation and no requirement for laboratory infrastructure
- Automated data processing and library matching for clear results
Future Trends and Applications
Advancements in portable SERS technology are expected to enable multiplex detection of various contaminants. Integration with cloud-based platforms and improved nanoparticle substrates may further enhance sensitivity, data sharing, and real-time monitoring across supply chains.
Conclusion
The portable SERS approach offers a fast, sensitive, and field-deployable solution for detection of trace paraquat in tea leaves. Its simplicity and low detection limits support enhanced consumer safety and regulatory compliance.
Reference
AN-RS-025 Application Note, Metrohm AG
Content was automatically generated from an orignal PDF document using AI and may contain inaccuracies.
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