An optical fiber caffeic acid sensor using a molecularly-imprinted chitosan membrane as a transducer.

Predicted concentrations of 137Cs, 131I, 129I, 241Pu and 241Am in various foodstuffs following deposition to ground

Molecularly imprinted polymer for caffeic acid by precipitation polymerization and its application to extraction of caffeic acid and chlorogenic acid from Eucommia ulmodies leaves

The article critically examines the practice of post-Chernobyl standardisation of radionuclide concentrations (mainly 137Cs and 90Sr) in food products (FPs) in the USSR and the successor countries of Belarus, Russia and Ukraine. Recommendations are given on potential harmonisation of these standards of radionuclide concentrations in FPs among the three countries, taking into account substantial international experience. We propose to reduce the number of product groups for standardisation purposes from the current amount of several dozens to three to five groups to optimise radiation control and increase the transparency of the process. We recommend five product groups for the standardisation of 137Cs and three groups for 90Sr in food in radiocontaminated areas. The values of standards for individual product groups are recommended to be set proportionally to the measured specific activity in each of these groups, which will reduce unreasonable food rejection. The standards might be set for the entire country, and could be also used to control imports from other countries as well as exports to other countries. The developed recommendations were transferred in 2015–2016 to the regulatory authorities of the three countries.

A molecular imprint polymer (MIP) biosensor has been developed to determine caffeic acid in misai kucing (Orthosiphon stamineus) samples. The simulation of HyperChem 8.0 software gave a suitable template and functional monomer ratio for the MIP preparation. The MIPs were prepared by non-covalent bulk polymer approach. The analytical performance of MIP and NIP studies were based on the frequency change of mass sensitive quartz crystal microbalance sensor. The MIP biosensor showed good sensitivity to caffeic acid from 1.5 ng/ml - 12.5 ng/ml with a R2 value of 0.98 whereas NIP sensor showed very low response. The caffeic acid in O. stamineus extract and two commercial products were quantified using the MIP biosensor

Specific recognition of polyphenols by molecularly imprinted polymers based on a ternary deep eutectic solvent

N-nitrosamines formed in meat products, especially during heat treatment, are potentially hazardous to human health. Smoked sausages are a product with a high content of N-nitrosamines, including those not regulated in Russia, which can cause health risks for population. The aim of this study was to perform health risk assessment considering ratios of N-nitrosamine concentrations in food products. The data on N-nitrosamines’ concentrations were analyzed using MS Excel and Statistica 10.0 programs. The relationship between these concentrations was evaluated using Spearman correlation coefficient. Parameterization of dependencies was carried out by regression analysis with evaluation of model significance by Fisher's criterion. Differences at the level of p ≤ 0.05 were considered statistically significant. Risk assessment was performed in accordance with the Guideline R.2.1.10.3968-23. Correlation analysis between N-nitrosamines in smoked sausages revealed a significant correlation between concentrations of NDMA and NEMA (rs = 0.77) and NDMA and NPyRA (rs = 0.81) at p < 0.05. The level of total carcinogenic risk (∑CR) derived from data based on calculated concentrations of NEMA and NPyRA was determined to be unacceptable for the adult population. It should be noted that the contribution to ∑CR value (11.0 %) is related to NEMA and NPyRA that are not regulated in Russia. Our study results support the findings of earlier EFSA publications indicating that not only NDMA and NDEA, but also other N-nitrosamines may form a health risk upon simultaneous exposure. Correlation and regression analyses allowed us to assess the concentrations of NEMA and NPyRA in sausages. Use of both these concentrations and actual NDMA and NDEA concentrations established unacceptable carcinogenic risk for certain consumer groups in case N-nitrosamines concentrations were above regulated level. The contribution of NEMA and NPyRA in ∑CR value was 11.0 %.

Separation and purification of the antioxidant compounds, caffeic acid phenethyl ester and caffeic acid from mushrooms by molecularly imprinted polymer

Microbial concentration in samples of a food product lot has been generally assumed to follow the log-normal distribution in food sampling, but this distribution cannot accommodate the concentration of zero. In the present study, first, a probabilistic study with the most probable number (MPN) technique was done for a target microbe present at a low (or zero) concentration in food products. Namely, based on the number of target pathogen-positive samples in the total samples of a product found by a qualitative, microbiological examination, the concentration of the pathogen in the product was estimated by means of the MPN technique. The effects of the sample size and the total sample number of a product were then examined. Second, operating characteristic (OC) curves for the concentration of a target microbe in a product lot were generated on the assumption that the concentration of a target microbe could be expressed with the Poisson distribution. OC curves for Salmonella and Cronobacter sakazakii in powdered formulae for infants and young children were successfully generated. The present study suggested that the MPN technique and the Poisson distribution would be useful for qualitative microbiological test data analysis for a target microbe whose concentration in a lot is expected to be low.

Molecularly imprinted polymer for chlorogenic acid by modified precipitation polymerization and its application to extraction of chlorogenic acid from Eucommia ulmodies leaves

Synthesis of caffeic acid molecularly imprinted polymer microspheres and high-performance liquid chromatography evaluation of their sorption properties

Poly(caffeic acid)-coated molecularly imprinted magnetic nanoparticles for specific and ultrasensitive detection of glycoprotein.

Molecular imprinting is an efficient strategy to make the detection of compounds more specific and more selective. This targeted analytical strategy using molecularly imprinted polymer (MIP) synthesis needs to obtain the optimized conditions. A selective molecularly imprinted polymer was prepared for caffeic acid (CA) detection after varying the following synthesis parameters: functional monomer type (N-phenylacrylamide, N-PAA or methacrylic acid, MAA), solvent type (acetonitrile/methanol or acetonitrile/toluene), and the polymerization method (UV or thermal initiation). The optimal polymer was obtained using MAA as a functional monomer, acetonitrile/methanol as solvent, and UV polymerization. Morphological characterizations were done for the optimal CA-MIP using mid-infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption. The optimal polymer showed good specificity and selectivity in the presence of interferents (antioxidants having a chemical structure close to CA) in a hydroalcoholic solution. The electrochemical detection of CA was performed by cyclic voltammetry (CV) after the interaction between CA and the optimal MIP in a wine sample. The linear range of the developed method was between 0 and 1.11 mM, the limit of detection (LOD) was 0.13 mM, and the limit of quantification (LOQ) was 0.32 mM. HPLC-UV was used to validate the newly developed method. Recovery values were between 104% and 111%.

The use of biomimetic sensor has attracted attention due to its sensitivity and selectivity. Molecular imprinted polymer (MIP) among the best synthetic biomimetic interfaces to detect target molecules. However MIP has low electrical conductivity. Sensor fabricated using high conductive polymer will possess a good sensitivity and short response time. Therefore, it is important to enhance the conductivity of MIP, thus it would directly influence charge carrier mobility of the polymer itself. The resulting rGO-MIP OTFT exhibit electrical conductivity of 3.10×10−3 Sm−1 at 0.4wt/vol% and MIP exhibit electrical conductivity of 7.16×10−4 Sm−1. The electrical conductivity of rGO-MIP increased about one in magnitude order compared to MIP. Moreover, this work reports the electrical performance of reduce graphene oxide-molecular imprinted polymer organic thin film transistor (rGO-MIP OTFT) for serine detection. rGO was introduced into MIP, to allow a highly conductive sensing material thus enhanced selectivity and sensitivity of the sensor. By analyzing the electrical performance of the sensors, the performances of OTFT sensor enhanced with rGO-MIP interlayer and OTFT sensor with MIP interlayer when exposed to serine analyte were obtained. The results showed that there were remarkable shifts of drain current obtained from OTFT sensor with rGO-MIP interlayer after exposed to serine analyte. Moreover, the sensitivity of OTFT sensor with rGO-MIP interlayer was nearly higher than the OTFT sensor with MIP interlayer. Hence, it proved that rGO successfully enhanced the sensing performance of OTFT sensor.

Quinic acid (QA) and its ester conjugates have been subjected to in-depth scientific investigations for their antioxidant properties. In this study, molecularly imprinted polymers (MIPs) were used for selective extraction of quinic acid (QA) from coffee bean extract. Computational modelling was performed to optimize the process of MIP preparation. Three different functional monomers (allylamine, methacrylic acid (MAA) and 4-vinylpyridine (4-VP)) were tested for imprinting. The ratio of each monomer to template chosen was based on the optimum ratio obtained from computational studies. Equilibrium rebinding studies were conducted and MIP C, which was prepared using 4-VP as functional monomer with template to monomer ratio of 1:5, showed better binding performance than the other prepared MIPs. Accordingly, MIP C was chosen to be applied for selective separation of QA using solid-phase extraction. The selectivity of MIP C towards QA was tested versus its analogues found in coffee (caffeic acid and chlorogenic acid). Molecularly imprinted solid-phase extraction (MISPE) using MIP C as sorbent was then applied for selective extraction of QA from aqueous coffee extract. The applied MISPE was able to retrieve 81.918 ± 3.027% of QA with a significant reduction in the amount of other components in the extract.

A new method for the determination of the antiplatelet drug dipyridamole (DIP) in pharmaceuticals using a molecularly imprinted polymer (MIP)-modified pencil graphite electrode (PGE) is proposed. The modified electrode was prepared simply and rapidly by electropolymerization of caffeic acid (CA) in the presence of DIP and subsequent DIP extraction with ethanol, resulting in a cost-effective, eco-friendly disposable modified electrode (MIP_PGE). Several working conditions (monomer and template concentration, number of voltametric cycles, scan rate extraction time, and solvent) for the MIP_PGE preparation were optimized. The differential pulse voltammetric (DPV) oxidation signal of DIP obtained at MIP_PGE was 28% higher than that recorded at bare PGE. Cyclic voltammetry emphasized DIP irreversible, pH-dependent, diffusion-controlled oxidation at MIP_PGE. Differential pulse and adsorptive stripping voltammetry at MIP_PGE in phosphate buffer solution pH = 7.00 were applied for the drug quantitative determination in the range of 1.00 × 10−7–1.00 × 10−5 and 1.00 × 10−8–5.00 × 10−7 mol/L DIP, respectively. The obtained limits of detection were at the tens nanomolar level.