Development and validation of a high-throughput online solid phase extraction - Liquid chromatography - Tandem mass spectrometry method for the detection of tetrodotoxin in human urine

Determination of tetrodotoxin in human plasma and urine using online MCX SPE column cleanup coupled with liquid chromatography-tandem mass spectrometry

An efficient technique for quantitative analysis of tetrodotoxin (TTX) in human plasma and urine has been developed, which combines liquid chromatography-tandem mass spectrometry (LC-MS/MS) with online MCX solid phase extraction (SPE) cleanup. Sample preparation, including extraction with acetonitrile containing 0.5 % acetate acid, centrifugation, and filtration, was followed by online SPE cleanup. The whole run-time was less than 15 min, including online cleanup, chromatographic separation, and re-equilibration of the online SPE - LC-MS/MS system. The parameters of sample extraction, purification, separation, and detection were optimized. The matrix-matched internal standard calibration standard curves with linear regression coefficients larger than 0.9990 were established for quantification. The LOD and LOQ for this approach were determined to be 0.1 ng/mL and 0.3 ng/mL, respectively. The recoveries for varied concentrations of TTX in human plasma and urine were 84.9-104.2 % and 89.2-109.6 %, respectively. The matrix effects of TTX in human plasma and urine matrices were 85.5 % and 74.3 %, respectively, and both the inter- and intra-day precision values were less than 9.5 %. This analytical method was successfully employed for detecting TTX in biological samples from a poisoned patient who accidentally ingested the nassarius glans.

Analytical Method Optimization of Tetrodotoxin and Its Contamination in Gastropods

Tetrodotoxin (TTX) is an extremely potent marine biotoxin. An analytical method was developed for both trace contamination and extremely high levels of TTX in gastropods by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with clean-up of cation exchange solid phase extraction (SPE) in this study. The limit of detection (LOD) in the sample matrix was 0.5 μg/kg. With the calibration of a screened internal standard (validamycin, IS), the linear range was 0.1-100 ng/mL (1.5-1500 μg/kg in sample matrix) with a correlation coefficient of r2 > 0.999. The average recoveries at three spiking levels (1.5 μg/kg, 44 μg/kg, and 1500 μg/kg) were 82.6-94.4% with relative standard deviations (RSDs) less than 8.4%. TTX levels in seven gastropods (741 samples) were studied. The contamination and analogues in Neverita didyma (N. didyma, 565 samples collected in Zhejiang province, China, from 2016 to 2022) were first reported. The detection rate of TTX in N. didyma was 34.2%. The average concentration was 23.1 μg/kg, and the maximum value was 2327 μg/kg. The time distribution study indicated that high contaminations of TTX occurred from May to August for N. didyma.

Tetrodotoxin and Its Analogues in Food: Recent Updates on Sample Preparation and Analytical Methods Since 2012

Tetrodotoxin (TTX), found in various organisms including pufferfish, is an extremely potent marine toxin responsible for numerous food poisoning accidents. Due to its serious toxicity and public health threat, detecting TTX and its analogues in diverse food matrices with a simple, fast, efficient method has become a worldwide concern. This review summarizes the advances in sample preparation and analytical methods for the determination of TTX and its analogues, focusing on the latest development over the past five years. Current state-of-the-art technologies, such as solid-phase microextraction, online technology, novel injection technology, two-dimensional liquid chromatography, high-resolution mass spectrometry, newly developed lateral flow immunochromatographic strips, immunosensors, dual-mode aptasensors, and nanomaterials-based approaches, are thoroughly discussed. The advantages and limitations of different techniques, critical comments, and future perspectives are also proposed. This review is expected to provide rewarding insights to the future development and broad application of pretreatment and detection methods for TTX and its analogues.

Simultaneous Determination of Tetrodotoxin in the Fresh and Heat-Processed Aquatic Products by High-Performance Liquid Chromatography-Tandem Mass Spectrometry

Tetrodotoxin (TTX) was simultaneously detected in the fresh and heat-processed aquatic products by high-performance liquid chromatography-tandem mass spectrometry method. The detection conditions were investigated, including the chromatography column and mobile phase. Based on the optimized parameters, a sensitive determination method of TTX was established. The proposed method featured the merits of a good linear relationship between signal and TTX concentration (R2 = 0.9998), a wide detection matrix-based range of 0.2-100 ng/g, and a low detection limit of 0.2 ng/g, etc. The spiked assays evidenced its accuracy and reliability with recoveries of 90.5-107.2%. Finally, the developed method was simultaneously successfully applied in the determination of TTX in various fresh and heat-processed aquatic products.

A cluster of tetrodotoxin poisoning in Oman

INTRODUCTION

Tetrodotoxin (TTX) is a potent sodium channel blocker, with significant neurotoxicity, found in marine animals like pufferfish and blue-ringed octopus. The severity of toxicity depends on the amount of toxin ingested and the outcome depends on the time-lapse to appropriate medical care.

CASES REPORT

We report five patients who presented with tetrodotoxin poisoning after consuming fried internal organs of local pufferfish from the coast of Oman. The patients' clinical manifestations were consistent with the expected TTX toxidrome of perioral and generalized paresthesia, weakness of upper and lower extremities, gastrointestinal manifestations, dyspnea, dysarthria, ascending paralysis, hypotension, bradycardia and coma. The severity varied among the patients who recovered completely except one patient who developed a subarachnoid hemorrhage without underlying aneurysms on computed tomography-angiogram. This complication was potentially related to TTX poisoning and has not been previously reported. In addition to standard supportive management, patients with severe illness should potentially receive the intravenous acetylcholinesterase inhibitor neostigmine, and intermittent dialysis. Urine specimens were sent to CDC in Atlanta, where they were analyzed using online solid phase extraction (SPE) with LC-MS/MS and confirmed the diagnosis in all five cases.

DISCUSSION

In general, the patients' clinical manifestations were consistent with the expected TTX toxidrome except patient 3 who developed a subarachnoid hemorrhage early during his clinical course. Two patients received neostigmine and underwent dialysis with complete recovery.

Hydrophilic Interaction Liquid Chromatography (HILIC): Latest Applications in the Pharmaceutical Researches

Background:

Significant advances have been occurred in analytical research since the 1970s by Liquid Chromatography (LC) as the separation method. Reverse Phase Liquid Chromatography (RPLC) method, using hydrophobic stationary phases and polar mobile phases, is the most commonly used chromatographic method. However, it is difficult to analyze some polar compounds with this method. Another separation method is the Normal Phase Liquid Chromatography (NPLC), which involves polar stationary phases with organic eluents. NPLC presents low-efficiency separations and asymmetric chromatographic peak shapes when analyzing polar compounds. Hydrophilic Interaction Liquid Chromatography (HILIC) is an interesting and promising alternative method for the analysis of polar compounds. HILIC is defined as a separation method that combines stationary phases used in the NPLC method and mobile phases used in the RPLC method. HILIC can be successfully applied to all types of liquid chromatographic separations such as pharmaceutical compounds, small molecules, metabolites, drugs of abuse, carbohydrates, toxins, oligosaccharides, peptides, amino acids and proteins.

Objective:

This paper provides a general overview of the recent application of HILIC in the pharmaceutical research in the different sample matrices such as pharmaceutical dosage form, plasma, serum, environmental samples, animal origin samples, plant origin samples, etc. Also, this review focuses on the most recent and selected papers in the drug research from 2009 to the submission date in 2020, dealing with the analysis of different components using HILIC.

Results and Conclusion:

The literature survey showed that HILIC applications are increasing every year in pharmaceutical research. It was found that HILIC allows simultaneous analysis of many compounds using different detectors.

A simple, versatile, and automated pulse-diffusion-focusing strategy for sensitive milliliter-level-injection HILIC-MS/MS analysis of hydrophilic toxins

The measurement of trace hydrophilic toxins in complex aqueous-rich matrices is a daunting challenge. To address this analytical bottleneck, pulse diffusion focusing (PDF), a novel sample injection technique for hydrophilic interaction chromatography-tandem mass spectrometry (HILIC-MS/MS), was developed. Theoretical and experimental investigations of the mechanism and key parameters revealed that the pulse-injection approach, assisted by solvent diffusion, efficiently solved the volume overload problem. This milliliter-level-injection HILIC-MS/MS technique was reported for the first time herein, and provided a significant enhancement in sensitivity compared to the conventional injection method, in addition to being an efficient approach to address the solvent incompatibility of off-line sample preparation and HILIC. The automated PDF-HILIC-MS/MS system was obtained by slightly modifying a commercial LC-MS/MS instrument in an easy and economical manner. The efficiency of the system was demonstrated through the detection of trace tetrodotoxin contents in plasma and urine samples. Low limits of detection (i.e., 0.65 and 2.2 ng·mL^-1) were obtained using the simplified sample preparation method. The recoveries were in the range 91-113.3 % with intra-day and inter-day precisions of ≤9.6 %. Further experimental results proved the method to be versatile for various hydrophilic toxins.

Chronic In Vivo Effects of Repeated Exposure to Low Oral Doses of Tetrodotoxin: Preliminary Evidence of Nephrotoxicity and Cardiotoxicity

Tetrodotoxin (TTX) is one of the most potent naturally occurring neurotoxins. InitiallyTTX was associated with human food intoxications in Japan, but nowadays, concerns about thehuman health risks posed by TTX have increased in Europe after the identification of the toxin infish, marine gastropods, and bivalves captured in European waters. Even when TTX monitoring isnot currently performed in Europe, an acute oral no observable effect level (NOAEL) of 75 μg/kghas been recently established but, to date, no studies evaluating the chronic oral toxicity of TTXhave been released, even when EFSA has highlighted the need for them. Thus, in this work, thechronic effects of low oral TTX doses (below the acute lethal dose 50) were evaluated followinginternationally adopted guidelines. The results presented here demonstrate that low oral doses ofTTX have deleterious effects on renal and cardiac tissues. Moreover, alterations in bloodbiochemistry parameters, urine production, and urinalysis data were already detected at the oraldose of 75 μg/kg after the 28 days exposure. Thus, the data presented here constitute an initialapproach for the chronic evaluation of the in vivo toxicity of tetrodotoxin after its ingestion throughcontaminated fishery products.

Multiplexed ELISA screening assay for nine paralytic shellfish toxins in human plasma

Paralytic shellfish poisoning is a lethal syndrome that can develop in humans who consume shellfish contaminated with paralytic shellfish toxins. This rapid screening assay can be used to quickly diagnose exposure to paralytic shellfish toxins.

Detecting Biothreat Agents: From Current Diagnostics to Developing Sensor Technologies

Although a fundamental understanding of the pathogenicity of most biothreat agents has been elucidated and available treatments have increased substantially over the past decades, they still represent a significant public health threat in this age of (bio)terrorism, indiscriminate warfare, pollution, climate change, unchecked population growth, and globalization. The key step to almost all prevention, protection, prophylaxis, post-exposure treatment, and mitigation of any bioagent is early detection. Here, we review available methods for detecting bioagents including pathogenic bacteria and viruses along with their toxins. An introduction placing this subject in the historical context of previous naturally occurring outbreaks and efforts to weaponize selected agents is first provided along with definitions and relevant considerations. An overview of the detection technologies that find use in this endeavor along with how they provide data or transduce signal within a sensing configuration follows. Current "gold" standards for biothreat detection/diagnostics along with a listing of relevant FDA approved in vitro diagnostic devices is then discussed to provide an overview of the current state of the art. Given the 2014 outbreak of Ebola virus in Western Africa and the recent 2016 spread of Zika virus in the Americas, discussion of what constitutes a public health emergency and how new in vitro diagnostic devices are authorized for emergency use in the U.S. are also included. The majority of the Review is then subdivided around the sensing of bacterial, viral, and toxin biothreats with each including an overview of the major agents in that class, a detailed cross-section of different sensing methods in development based on assay format or analytical technique, and some discussion of related microfluidic lab-on-a-chip/point-of-care devices. Finally, an outlook is given on how this field will develop from the perspective of the biosensing technology itself and the new emerging threats they may face.

Capillary electrophoresis-tandem mass spectrometry for multiclass analysis of polar marine toxins

Polar marine toxins are more challenging to analyze by mass spectrometry-based methods than lipophilic marine toxins, which are now routinely measured in shellfish by multiclass reversed-phase liquid chromatography-tandem mass spectrometry (MS/MS) methods. Capillary electrophoresis (CE)-MS/MS is a technique that is well suited for the analysis of polar marine toxins, and has the potential of providing very high resolution separation. Here, we present a CE-MS/MS method developed, with use of a custom-built interface, for the sensitive multiclass analysis of paralytic shellfish toxins, tetrodotoxins, and domoic acid in seafood. A novel, highly acidic background electrolyte (5 M formic acid) was designed to maximize protonation of analytes and to allow a high degree of sample stacking to improve the limits of detection. The method was applied to a wide range of regulated and less common toxin analogues, and exhibited a high degree of selectivity between toxin isomers and matrix interference. The limits of detection in mussel tissue were 0.0052 mg/kg for tetrodotoxins, 0.160 mg/kg for domoic acid, and between 0.0018 and 0.120 mg/kg for paralytic shellfish toxins, all of which showed good linearity. Minimal ionization suppression was observed when the response from neat and mussel-matrix-matched standards was corrected with multiple internal standards. Analysis of shellfish matrix reference materials and spiked samples demonstrated good accuracy and precision. Finally, the method was transferred to a commercial CE-MS/MS system to demonstrate its widespread applicability for use in both R & D and routine regulatory settings. The approach of using a highly acidic background electrolyte is of broad interest, and can be considered generally applicable to simultaneous analysis of other classes of small, polar molecules with differing pK_a values. Graphical abstract ᅟ.

Rapid and Sensitive ELISA Screening Assay for Several Paralytic Shellfish Toxins in Human Urine

Paralytic shellfish poisoning is caused by a group of paralytic shellfish toxins that are produced by dinoflagellates. Toxins in this group include saxitoxin, neosaxitoxin and gonyautoxins. A rapid diagnostic test to identify poisoning by these toxins can be helpful in guiding the appropriate treatment of victims. Additionally, quick receipt of diagnostic results can provide timely proof that shellfish harvesting should be stopped in a given area, thereby preventing additional exposures. We have developed and validated a rapid urinary enzyme-linked immunosorbent assay-based screening test to diagnose exposure to several major paralytic shellfish toxins. The lower limit of detection (LLOD) for multiple paralytic shellfish toxins was characterized as 0.02, 0.10, 0.10, 1.0, 1.0 and 15 ng/mL for saxitoxin, gonyautoxin 2,3, decarbamoyl gonyautoxin 2,3, decarbamoyl saxitoxin, neosaxitoxin and gonyautoxin 1,4, respectively. No interferences were identified in unspiked pooled urine or in specimens collected from unexposed individuals indicating that this method is specific for the paralytic shellfish toxins tested. The accuracy of this test was demonstrated in 10 individual urine specimens with osmolalities ranging from 217 to 1,063 mOsmol/kg and pHs ranging between 5.06 and 7.45. These specimens were spiked with toxins at their LLODs and the presence of toxins at these concentrations was accurately identified in all cases. These results indicate that this diagnostic test can be used to rapidly and accurately screen urine for paralytic shellfish toxins.