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Glyphosate is a commonly used herbicide that can kill some weeds and grasses. Unfortunately, exposure to glyphosate is considered potentially harmful to humans. It may cause liver and kidney damage as well as can affect the endocrine system.1 Furthermore, the International Agency for Research on Cancer considers glyphosate as a probable carcinogen.2 Glyphosate determination often requires additional steps allowing quantification by commonly employed chromatographic techniques. Therefore, low-cost, rapid, and reliable ways to determine this pesticide are essential. We devised and fabricated an electrochemical chemosensor for the selective determination of the target toxin, glyphosate. As a recognition unit in this sensor, electroactive molecularly imprinted nanoparticles (nanoMIPs) with an internal redox probe were used.3 The MIP nanoparticles were synthesized using a solid-phase synthesis protocol.4 The nanoMIPs were characterized by several methods, including dynamic light scattering (DLS), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The obtained nanoparticles were covalently immobilized on screen-printed platinum electrodes and successfully used for electrochemical determination of glyphosate in the absence of any external redox probe. Chemosensor fabricated that way demonstrated high sensitivity and selectivity with respect to structural analogs of glyphosate and other phosphate-containing analytes. The practical application of this self-reporting MIP-based chemosensor for detecting pesticide was further verified in river water samples with satisfying results. These results prove that our sensor's detectability is sufficient for the on-site detection of glyphosate pesticide. References: 1 Myers, J. P., Antoniou, M. N., Blumberg, B. et al. Concerns over use of glyphosate-based herbicides and risks associated with exposures: a consensus statement. Environ Health. 15, 19 (2016) 2 Guyton, K. Z., Loomis, D., Grosse, Y. et al. International Agency for Research on Cancer Monograph Working Group ILF. Carcinogenicity oftetrachlorvinphos, parathion, malathion, diazinon, and glyphosate. Lancet Oncol. 16, 490-491 (2015) 3 Cruz, A. G., Haq, I., Cowen, T. et al. Design and fabrication of a smart sensor using in silico epitope mapping and electro-responsive imprinted polymer nanoparticles for determination of insulin levels in human plasma. Biosens. Bioelectron. 169, 112536 (2020) 4 Canfarotta, F., Poma, A., Guerreiro, A. et al. Solid-phase synthesis of molecularly imprinted nanoparticles. Nat Protoc 11, 443–455 (2016)

Quinoxaline heterocyclic aromatic amines (HAAs), are formed during meat and fish cooking, frying, or grilling at high temperatures. HAAs are classified as potent hazardous carcinogens, even though the HAAs are usually generated at very low concentrations (~ng per g of a food sample). This is because the HAA food contaminants effectively damage DNA by intercalation or strand break. Hence, chronic exposure to HAAs, even in low doses, can cause cancers of the lung, stomach, breast, etc. Currently, HPLC is used for the determination of these toxins in food matrices. However, this technique is expensive, tedious, and time-consuming. Therefore, fast, simple, inexpensive, and reliable HAAs determination procedures, without the need for separation of these toxins, in the protein food matrices are in demand. Molecularly imprinted polymers (MIPs) are excellent examples of bio-mimicking recognition materials. Therefore, they have found numerous applications in selective chemosensing. Within the present project, we synthesized a nucleobase-functionalized molecularly imprinted polymer (MIP) as the recognition unit of an electrochemical sensor for selective DPV and capacitive detection and determination of 2-amino-3,7,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) HAA. MIP-(7,8-DiMeIQx) film-coated electrodes were sensitive and selective to 7,8-DiMeIQx. The linear dynamic concentration range of the devised chemosensor extended from 12 µM to 0.4 mM 7,8-DiMeIQx and the imprinting factor was high, IF = 13. The present work is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 711859. Scientific work was funded from the financial resources for science in the years 2017-2021 awarded by the Polish Ministry of Science and Higher Education for the implementation of an international co-financed project and National Science Centre Poland (grant No. NCN 2014/15/B/NZ7/01011 to W.K.)

Quinoxaline heterocyclic aromatic amines (HAAs), are formed during meat and fish cooking, frying or grilling at high temperatures. HAAs are classified as potent hazardous carcinogens, even though the HAAs are usually generated at very low concentration (~ng per g of a food sample). This is because the HAA food contaminants effectively damage DNA by intercalation or strand break. Hence, chronic exposure to HAAs, even in low doses, can cause cancers of lung, stomach, breast, etc. Currently, HPLC is used for determination of these toxins in food matrices. However, this technique is expensive, tedious, and time-consuming. Therefore, fast, simple, inexpensive, and reliable HAAs determination procedures, without need of separation of these toxins, in the protein food matrices are in demand. Molecularly imprinted polymers (MIPs) are excellent examples of bio-mimicking recognition materials. Therefore, they have found numerous applications in selective chemosensing. Within the present project, we synthesized a nucleobase-functionalized molecularly imprinted polymer (MIP) as the recognition unit of a chemosensor for selective detection and determination of 2-amino-3,7,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (7,8-DiMeIQx) HAA. MIP-(7,8-DiMeIQx)-film coated electrodes were sensitive and selective with respect to 7,8-DiMeIQx. The linear dynamic concentration range of the devised chemosensor extended from 12 µM to 0.4 mM 7,8-DiMeIQx and the imprinting factor was high, IF = 14. This work is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 711859. Scientific work was funded from the financial resources for science in the years 2017-2021 awarded by the Polish Ministry of Science and Higher Education for the implementation of an international co-financed project and National Science Centre Poland (grant No. NCN 2014/15/B/NZ7/01011 to W.K.)

High-temperature processing of meat food generates in it toxic heteroaromatic amines and nitrosamines (NAs)1,2 causing chronic diseases including hormonal dysfunctions and cancer.3 Therefore, we devised and fabricated chemical sensors for selective determination of the N-nitroso-L-proline (Pro-NO)4 and N-nitroso-thiazolidine-4-carboxylic acid (NT4A) toxins in this food. We applied films of conducting polymers molecularly imprinted (MIPs) with either the Pro-NO or NT4A template as recognition units of these chemosensors. For selection of most appropriate functional monomers, we used DFT at the B3LYP/3-21G(*) level modeling to find phenolic derivative of bis(bithiophene) and a thiosalenCo(III) complex (CS)5,6 suitable to form pre-polymerization complexes with Pro-NO and NT4A, respectively, at the 1:2 template/monomer stoichiometry. The calculated Gibbs free energy gain due to formation of these complexes with a series of NAs was proportional to the UV-vis spectroscopy determined stability constants of these complexes. These constants were relatively high equalling 3.14×109 M-2 and 2.72×1010 M-2for Pro-NO and NT4A, respectively. Then, we electrochemically polymerized these complexes under potentiodynamic conditions. This electropolymerization resulted in depositing thin MIP films on different electrode substrates. After subsequent extraction of the Pro-NO and NT4A templates from MIPs, we used the resulting MIPs with empty imprinted cavities for determination of Pro-NO and NT4A analytes in grilled pork neck samples. We confirmed the presence and then absence of NA templates in the MIP films before and after extraction, respectively, with FTIR spectroscopy and XPS, and then characterized morphology of the films with AFM. For analytical signal transduction, we used piezoelectric microgravimetry (PM) at the Au-QCR/MIP electrodes of EQCM as well as DPV and EIS at the Pt/MIP electrodes. Limits of detection of the chemosensors were 36.9 nM Pro-NO (with EIS) and 46 nM NT4A (with DPV). The chemosensors selectively responded to the target toxins in the presence of interfering compounds of similar composition and structure. Successful selective determination of Pro-NO and NT4A in the food extract samples indicates that the chemosensors are promising as tools for determination of these toxins in food of animal origin. References 1. Santarelli R. L. et al., Nutr. Cancer 2008, 60, 131. 2. Oostindjer, M. et al., Meat Sci. 2014, 97, 583. 3. Larsson S. C. et al., Int. J. Cancer 2006, 119, 915. 4. Lach P. et al., Chem. Eur. J.(2016) in press, DOI:10.1002/chem.201604799. 5. Pan, M.; et al., Biosens. Bioelectron. 2012, 31, 11. 6. Zhao, L.; et al., Sens. Actuators, B Chem. 2012, 171–172, 563. Figure 1