Testing Water and Spinach for Multiple Toxins Using Advanced Tech

David Palenski
25th January, 2024

Testing Water and Spinach for Multiple Toxins Using Advanced Tech

Spinach (Spinacia oleracea), one the toxin target's of the study along with water.

Photo adapted from: Vasyliuk Oleksij / CC BY (Source)
Cyanotoxins, toxic chemicals produced by certain bacteria called cyanobacteria, represent a growing public health concern globally. These bacteria are ancient, dating back 3.5 billion years[2], and thrive in both freshwater and marine environments. Their proliferation, often spurred by factors like agricultural runoff and climate change, leads to blooms that can contaminate water supplies and pose risks to humans and animals. While the presence of cyanotoxins in water is well-established, understanding the extent of exposure, particularly through less obvious routes like food consumption, remains a challenge. Researchers at the University of Granada have recently developed a new method for detecting multiple cyanotoxins in both water and food samples[1]. The core problem is that current methods for identifying and quantifying cyanotoxins can be complex, time-consuming, and may not be sensitive enough to detect the low concentrations that can still be harmful with chronic exposure[3]. Existing techniques also often focus on detecting only a few types of cyanotoxins at a time, while a wide variety exists, differing in their chemical structure and toxicity. This new study addresses these limitations by providing a single analytical approach capable of simultaneously detecting eight common cyanotoxins from three different chemical classes: cyclic peptides, alkaloids, and non-protein amino acids. The study’s innovation lies in the combination of two analytical techniques: capillary electrophoresis (CE) and tandem mass spectrometry (MS/MS). Capillary electrophoresis separates molecules based on their electrical charge and size as they move through a narrow capillary tube. Tandem mass spectrometry then identifies and quantifies these separated molecules based on their mass-to-charge ratio. This combination provides both high separation efficiency and sensitive detection. The researchers optimized the process by carefully selecting the chemical environment within the capillary and fine-tuning the mass spectrometer settings. To enhance the sensitivity of the method, the researchers employed several preconcentration strategies. These techniques effectively concentrate the cyanotoxins from the sample before analysis, allowing for the detection of even trace amounts. They used a combination of pH-junction, field-amplified sample stacking (FASS), and acid barrage – all methods that manipulate the electrical field to focus the cyanotoxins. This was coupled with a solid-phase extraction (SPE) system, a technique used to isolate the cyanotoxins from the sample matrix. The result was a method capable of detecting cyanotoxins in water at concentrations as low as 0.005 to 0.10 micrograms per liter. Importantly, the researchers extended their method beyond water analysis. They successfully applied it to spinach samples, a potential pathway for human exposure to cyanotoxins. Edible plants can absorb cyanotoxins from contaminated irrigation water or directly from the environment. The spinach samples were first freeze-dried (lyophilisation) and then extracted using a methanol-water mixture before analysis using the same SPE procedure and CE-MS/MS technique. This demonstrates the method’s versatility and its potential for monitoring cyanotoxin contamination in the food chain. The increasing frequency and extent of harmful cyanobacterial blooms[4] highlight the need for robust monitoring strategies. While much research has focused on the dangers of drinking contaminated water, or recreational exposure[5], this study underscores the importance of considering dietary exposure as well. The ability to accurately identify and quantify a range of cyanotoxins in both water and food samples, as demonstrated by the University of Granada team, represents a significant step forward in protecting public health. The method developed aligns with the principles of “green analytical chemistry” by aiming for environmentally friendly and efficient analytical techniques.

VegetablesEnvironmentBiochem

References

Main Study

1) Capillary electrophoresis tandem mass spectrometry to determine multiclass cyanotoxins in reservoir water and spinach samples.

Published 22nd January, 2024

https://doi.org/10.1016/j.chroma.2024.464666

Related Studies

2) Cyanotoxins: producing organisms, occurrence, toxicity, mechanism of action and human health toxicological risk evaluation.

https://doi.org/10.1007/s00204-016-1913-6

3) The Diversity of Cyanobacterial Toxins on Structural Characterization, Distribution and Identification: A Systematic Review.

https://doi.org/10.3390/toxins11090530

4) Toxic Cyanobacteria: A Growing Threat to Water and Air Quality.

https://doi.org/10.1021/acs.est.0c06653

5) Acute animal and human poisonings from cyanotoxin exposure - A review of the literature.

https://doi.org/10.1016/j.envint.2016.02.026


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