Advanced systems for the rapid detection of anthelmintic drugs in food

Several surface plasmon resonance (SPR) biosensor assays were developed and validated for the detection of anthelmintic veterinary drugs in liver tissue and milk using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction procedure. The first screening assay was developed to detect 11 benzimidazole carbamates in milk and liver. In bovine milk the assay showed a limit of detection (LOD) of 2.7 μg kg-1 and a detection capability (CCβ) of 5 μg kg-1. Analyte recovery was in the range 81 to 116% and the assay was found to be fit for purpose when its performance was compared to UPLC-MS/MS analyses of milk from cows treated with benzimidazole products. In bovine liver the LOD (32 μg kg-1) and the CCβ (50 μg kg-1) were determined and the analyte recovery was in the range 77-132%. All non-compliant samples were identified when the assay performance was tested by analysing liver from animals treated with benzimidazole drugs and comparing the results with a UPLC-MS/MS confirmatory method. A screening assay was developed for four amino-benzimidazoles in liver. The LOD (41 μg kg-1) and the CCβ (75 μg kg-1) were determined and the analyte recovery was in the range 103-116%. A screening assay for thiabendazole and 5-hydroxy-thiabendazole in ovine liver tissue using a novel recombinant antibody fragment (Fab) was developed. The LOD (12.3 μg kg-1), the CCβ (20 μg kg-1) and analyte recovery (86-107%) satisfied the criteria required for thiabendazole screening in liver tissue. A biosensor to detect triclabendazole residues in liver tissue was developed through the immobilization of amino-triclabendazole via a glutaraldehyde homo-bifunctional crosslinker. Several experiments were required to reduce non-specific binding in this assay. An LOD of 105 μg kg-1 was determined which was close to the maximum residue limit (MRL) in liver matrix (100 μg kg-1).A biochip array was developed and validated to screen orange juice for fungicide and pesticide residues. The LOD for carbendazim (20 μg kg-1), 2-aminobenzimidazole (4.0 μg kg-1), thiabendazole (4.2 μg kg-1) and ivermectin (10.2 μg kg-1) residues were determined. The CCβ for carbendazim (50 μg kg-1), 2-aminobenzimidazole (10 μg kg- 1), thiabendazole (10 μg kg-1) and ivermectin (20 μg kg-1) residues were sufficient for the analysis of orange juice. When orange juice from retail outlets in the greater Dublin area (n = 15) Two samples contained thiabendazole residues above the CCβ (260 and 181 μg kg-1) however these concentrations were below the maximum residue limit

Novel Analytical Methods in Food Analysis

This reprint provides information on the novel analytical methods used to address challenges occurring at academic, regulatory, and commercial level. All topics covered include information on the basic principles, procedures, advantages, limitations, and applications. Integration of biological reagents, (nano)materials, technologies, and physical principles (spectroscopy and spectrometry) are discussed. This reprint is ideal for professionals of the food industry, regulatory bodies, as well as researchers

Multiplex biosensor immunoassays for antibiotics in the food chain

The use of antibiotics in food-producing animals may result in unwanted residues in food products. The main objective of the present research was to study the development and application of fast and automated multiplex surface plasmon resonance (SPR)-based biosensor immunoassays (BIAs), based on multi-component antibodies and/or combined immunoassays in serially connected flow channels, for the detection of selected antibiotics in the food chain. The scientific challenges to deal with were: the development of multi-sulfonamide monoclonal antibodies (Mabs) against the generic structure of sulfonamides and the evaluation of mutated recombinant antibodies (Rabs) derived thereof, finding of the best BIA format with aminoglycosides as model compounds and solving foreseen matrix and combined immunoassay interferences, and to study the use of antibiotic concentrations in blood serum as predictors for concentrations in edible tissue. Broiler’s blood serum, easy to collect in slaughterhouses, was chosen for the detection of sulfonamides and quinolones which are frequently used in poultry. With a Mab raised against sulfamethazine (21C7), the BIA could detect at least eight sulfonamides in ten times diluted broiler serum with limits of detection (LODs) far below the desired detection limit. Other less performing Mabs were developed against the generic part of sulfonamides. The best Mab-producing hybridoma cell-line (27G3) was used by the University of Turku to develop better performing mutated Rabs and the mutant-based BIA in broiler serum was found to be the most sensitive towards most of the sulfonamides. The assay was fast (5 min per sample), robust (>1000 runs per chip) and the sample preparation was easy (dilution in buffer only). The Rab-based multi-sulfonamide immunoassay was applied to analyze serum samples from broilers treated with sulfamethoxazole and sulfadiazine and the concentrations found were higher than the concentrations found in tissue by LC-MS/MS. This, and the good correlation with tissue concentrations, made this assay suitable to predict levels in edible tissue. A similar result was obtained with the specific BIA for flumequine. Unique direct BIAs for the detection of aminoglycosides in milk were developed with Mab-coated chips. However, the inhibition assays with aminoglycosides on the chips were found to be more robust. For the simultaneous detection of five aminoglycosides in milk, the sensor chip surfaces in the four serially connected flow channels were covered with four aminoglycosides. In combination with a mixture of four specific antibodies, gentamicin, neomycin, kanamycin and (dihydro) streptomycin could be detected in milk far below the maximum residue limits (MRLs) and within 7 min. In conclusion, serum and milk are suitable sample materials for the biosensor detection of antibiotics in the food chain. Such assays are fast, robust, automated, easy to handle, and require simple sample preparations (dilutions in antibody-containing buffer). In principle, such assays can be combined with assays for the detection of anti-pathogens, which broadens the application area in a food safety control system. However, the four-channel biosensor systems are too limited and the antibodies too specific for the simultaneous detection of more antibiotics. More extended multiplex systems (e.g. imaging SPR sensors or multiplex flow cytometry-based systems) need to be explored in which the knowledge obtained in the present research will likely be of great value

Reproducible Molecularly Imprinted Piezoelectric Sensor for Accurate and Sensitive Detection of Ractopamine in Swine and Feed Products

This paper describes the development of a reproducible molecularly imprinted piezoelectric sensor for the accurate and sensitive detection of ractopamine (RAC) in swine and feed products. The synthesized molecularly imprinted polymer (MIP) was directly immobilized on the surface of a quartz crystal microbalance (QCM) Au chip as the recognition element. The experimental parameters in the fabrication, measurement and regeneration process were evaluated in detail to produce an MIP-based piezoelectric sensor with high sensing capability. The developed piezoelectric sensor was verified to perform favorably in the RAC analysis of swine and feed products, with acceptable accuracy (recovery: 75.9–93.3%), precision [relative standard deviation (n = 3): 2.3–6.4%], and sensitivity [limit of detection: 0.46 ng g−1 (swine) and 0.38 ng g−1 (feed)]. This portable MIP-based chip for the piezoelectric sensing of RAC could be reused for at least 30 cycles and easily stored for a long time. These results demonstrated that the developed MIP-based piezoelectric sensor presents an accurate, sensitive and cost-effective method for the quantitative detection of RAC in complex samples. This research offers a promising strategy for the development of novel effective devices used for use in food safety analysis

Reproducible Molecularly Imprinted Piezoelectric Sensor for Accurate and Sensitive Detection of Ractopamine in Swine and Feed Products

This paper describes the development of a reproducible molecularly imprinted piezoelectric sensor for the accurate and sensitive detection of ractopamine (RAC) in swine and feed products. The synthesized molecularly imprinted polymer (MIP) was directly immobilized on the surface of a quartz crystal microbalance (QCM) Au chip as the recognition element. The experimental parameters in the fabrication, measurement and regeneration process were evaluated in detail to produce an MIP-based piezoelectric sensor with high sensing capability. The developed piezoelectric sensor was verified to perform favorably in the RAC analysis of swine and feed products, with acceptable accuracy (recovery: 75.9–93.3%), precision [relative standard deviation (n = 3): 2.3–6.4%], and sensitivity [limit of detection: 0.46 ng g−1 (swine) and 0.38 ng g−1 (feed)]. This portable MIP-based chip for the piezoelectric sensing of RAC could be reused for at least 30 cycles and easily stored for a long time. These results demonstrated that the developed MIP-based piezoelectric sensor presents an accurate, sensitive and cost-effective method for the quantitative detection of RAC in complex samples. This research offers a promising strategy for the development of novel effective devices used for use in food safety analysis

New strategies for developing receptors based on molecular imprinting for analytical applications

434 p.La presente tesis se ha basado en la síntesis y aplicación de polímeros de huella molecular (MIP) para elanálisis químico del 4-etilfenol y los compuestos pertenecientes a su ruta metabólica, que son el etil esterde ácido cumárico, el ácido cumárico y el vinilfenol. Los fenoles volátiles como el 4-etilfenol y el 4-vinilfenol afectan a las características organolépticas del vino, siendo perjudiciales en altasconcentraciones. El nivel de 4-etilfenol es proporcional a la concentración y la actividad de la levaduraresponsable de su aparición en vino, y por lo tanto puede ser utilizado como un indicador de su presencia.El trabajo experimental se ha sido divido en dos secciones principales, en función de la técnica analíticaen la que ha sido implementado el material impreso desarrollado. Inicialmente, se presenta unametodología para el desarrollo y aplicación de fases estacionarias basadas en MIP. Los materialesdesarrollados han sido evaluados como fases estacionarias en extracción en fase sólida y cromatografíalíquida.Como segundo apartado del trabajo, se describen distintas técnicas de impresión molecular para suimplementación en sensores voltamperométricos, por un lado, la síntesis de películas MIP sobreelectrodos de oro y por otro, la síntesis de nanopartículas MIP y su posterior inmovilización en lasuperficie de electrodos de oro

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry was held on 1–15 July 2021. The scope of this online conference was to gather experts that are well-known worldwide who are currently working in chemical sensor technologies and to provide an online forum for the presention and discussion of new results. Throughout this event, topics of interest included, but were not limited to, the following: electrochemical devices and sensors; optical chemical sensors; mass-sensitive sensors; materials for chemical sensing; nano- and micro-technologies for sensing; chemical assays and validation; chemical sensor applications; analytical methods; gas sensors and apparatuses; electronic noses; electronic tongues; microfluidic devices; lab-on-a-chip; single-molecule sensing; nanosensors; and medico-diagnostic testing

Sewage sludge heavy metal analysis and agricultural prospects for Fiji

Insoluble residues produced in Waste Water Treatment Plants (WWTP) as by products are known as sewage sludge (SS). Land application of SS, particularly in agricultural lands, is becoming an alternative disposal method in Fiji. However, currently there is no legislative framework governing its use. SS together with its high nutrient and organic matter contents, constitutes some undesired pollutants such as heavy metals, which may limit its extensive use. The focus of this study therefore was to determine the total concentrations of Pb, Zn, Cd, Cu, Cr, Ni and Mn in the SS produced at the Kinoya WWTP (Fiji) and in the non-fertile soil amended with the SS at 20, 40, 60, 80% application rates and in the control (100% Soil). The bioavailable heavy metals were also determined as it depicts the true extent of metal contamination. The treatment mixtures were then used to cultivate cabbage plants in which the total heavy metal uptake was investigated. Total Zn (695.6 mg/kg) was present in the highest amounts in the 100% SS (control), followed by Pb (370.9 mg/kg), Mn (35.0 mg/kg), Cu (65.5 mg/kg), Cr (20.5 mg/kg) and finally Cd (13.5 mg/kg) and hence a similar trend was seen in all treatment mixtures. The potential mobility of sludgeborne heavy metals can be classified as Ni > Cu > Cd > Zn > Mn > Cr > Pb. Total metal uptake in plant leaves and stems showed only the bioavailable metals Cu, Cd, Zn and Mn, with maximum uptake occurring in the leaves. Ni, despite being highly mobile was not detected, due to minute concentrations in the SS treatments. Optimum growth occurred in the 20 and 40% SS treatments. However maximum Cu and Mn uptake occurred in the 40% SS treatment thereby making the 20% treatment the most feasible. Furthermore the total and bioavailable metal concentrations observed were within the safe and permitted limits of the EEC and USEPA legislations