Analysis of macrolide antibiotics in water by magnetic solid-phase extraction and liquid chromatography-tandem mass spectrometry

Developing a novel magnetic organic polymer for selective extraction and determination of 16 macrolides in water and honey samples

A novel magnetic organic polymer Fe3O4@SiO2@Tb-PDAN was designed and synthesized, which was used as an adsorbent for magnetic solid-phase extraction (MSPE) of 16 macrolides (MALs) in water and honey. The synthesized adsorbent was characterized using techniques including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Then several parameters of the extraction process were further optimized. Under the optimized conditions, an MSPE-LC-MS/MS method was established for extraction and determination of 16 MALs, which showed good linearity (r ≥ 0.999), low limits of detection (0.001-0.012 μg L-1 for water and 0.001-0.367 μg kg-1 for honey) and satisfactory recoveries (70.02-118.91%) with the relative standard deviations (RSDs) lower than 10.0%. This established method was then successfully applied to detect MALs in real samples, which suggested that Fe3O4@SiO2@Tb-PDAN was a potential magnetic adsorbent for efficient extraction and analysis of MALs.

Green microwave-prepared N and S Co-doped carbon dots as a new fluorescent nano-probe for tilmicosin detection

A straightforward, rapid, and selective fluorescent probe for determination of tilmicosin has been developed based on novel nitrogen and sulfur co-doped CDs (NS-CD). The NS-CDs were synthesized, for the first time, through green, simple one step microwave pyrolysis in only 90 s using glucose as carbon source and l-cysteine as nitrogen and sulfur source. This proposed synthesis method was energy-efficient and resulted in NS-CDs with high production yield (54.27 wt%) and narrow particle size distribution. Greenness of NS-CDs synthesis method was assessed using EcoScale and was proven to be excellent green synthesis. The produced NS-CDs were applied as a nano-probe for determination of tilmicosin in its marketed formulation and milk based on dynamic quenching mechanism. The developed probe showed a good performance for tilmicosin detection in marketed oral solution and pasteurized milk and linearity range of 9-180 μM and 9-120 μM, respectively.

Combining environmental, health, and safety features with a conductor like Screening Model for selecting green solvents for antibiotic analyses

Extraction and chromatographic techniques for analyzing pharmaceutically active compounds necessitate large quantities of organic solvents, resulting in a high volume of hazardous waste. The concept of green solvents focuses on protecting the environment by reducing or even eliminating the use of toxic solvents. The main objective of this critical review article is to build a framework for choosing green solvents for antibiotic analyses. The article briefly discusses the chemical properties of ciprofloxacin, sulfamethoxazole, tetracycline, and trimethoprim, and the current state of methodologies for their analyses in water and wastewater. It evaluates the greenness of solvents used for antibiotic analyses and includes insights on the comparison between conventional and green solvents for the analyses. An economic and environmental health and safety analysis combined with a Conductor-like Screening Model for Real Solvent (COSMO-RS) molecular simulation technique for predicting extraction efficiency was used in the evaluation. Methyl acetate and propylene carbonate tied for the greenest solvents from an environmental and economic perspective, whereas the COSMO-RS approach suggests dimethyl sulfoxide (DMSO) as the most suitable candidate. Although DMSO ranked third environmentally and economically, after methyl acetate and propylene carbonate, it would be an ideal replacement of hazardous solvents if it could be manufactured at a lower cost. DMSO showed the highest extraction capacity, as it can interact with antibiotics through hydrophobic interaction and hydrogen bonding. This article can be used as a green solvent selection guide for developing sustainable processes for antibiotic analyses.

Distribution of quinolone and macrolide resistance genes and their co-occurrence with heavy metal resistance genes in vegetable soils with long-term application of manure

The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) has become an increasingly serious global public health issue. This study investigated the distribution characteristics and influencing factors of ARB and ARGs in greenhouse vegetable soils with long-term application of manure. Five typical ARGs, four heavy metal resistance genes (MRGs), and two mobile genetic elements (MGEs) were quantified by real-time quantitative polymerase chain reaction (qPCR). The amount of ARB in manure-improved soil greatly exceeded that in control soil, and the bacterial resistance rate decreased significantly with increases in antibiotic concentrations. In addition, the resistance rate of ARB to enrofloxacin (ENR) was lower than that of tylosin (TYL). Real-time qPCR results showed that long-term application of manure enhanced the relative abundance of ARGs in vegetable soils, and the content and proportion of quinolone resistance genes were higher than those of macrolide resistance genes. Redundancy analysis (RDA) showed that qepA and qnrS significantly correlated with total and available amounts of Cu and Zn, highlighting that certain heavy metals can influence persistence of ARGs. Integrase gene intI1 correlated significantly with the relative abundance of qepA, qnrS, and ermF, suggesting that intI1 played an important role in the horizontal transfer of ARGs. Furthermore, there was a weakly but not significantly positive correlation between specific detected MRGs and ARGs and MGEs. The results of this study enhance understanding the potential for increasing ARGs in manure-applied soil, assessing ecological risk and reducing the spread of ARGs.

Occurrence, Comparison and Priority Identification of Antibiotics in Surface Water and Sediment in Urbanized River: A Case Study of Suzhou Creek in Shanghai

Antibiotics in water have attracted increasing attention due to their potential threat to aquatic ecosystems and public health. Most previous studies have focused on heavily polluted environments, while ignoring urbanized rivers with high population density. Taking Suzhou Creek in Shanghai as an example, this study attempted to explore the antibiotic pollution characteristics of typical urbanized rivers. Further, it screened out priority antibiotics so as to provide reference for the regular monitoring of antibiotics in urban surface water in the study’s later stage. Four classes of 27 antibiotics in surface water samples and sediment samples were detected and analyzed by SPE-UPLC-MS/MS under both wet season and dry season. Results demonstrate that the total amount of antibiotics detected reached 1936.9 ng/L and 337.3 ng/g in water samples and sediment samples, respectively. Through Pearson correlation analysis, it can be shown that there is a very significant correlation between a variety of antibiotics in water and sediment. The results of ecological risk assessment based on risk quotient (RQ) show that certain antibiotics presented high and medium risk to the surrounding ecosystem. Finally, the priority antibiotics selected by optimized priority screening method were EM, SPD, CLR and RTM. Therefore, we have proven that the antibiotics being discharged in urbanized rivers show different types of antibiotics, while presenting a toxicological risk to certain species.

Recent Advances and Perspectives on the Sources and Detection of Antibiotics in Aquatic Environments

Water quality and safety are vital to the ecological environment, social development, and ecological susceptibility. The extensive use and continuous discharge of antibiotics have caused serious water pollution; antibiotics are widely found in freshwater, drinking water, and reservoirs; and this pollution has become a common phenomenon and challenge in global water ecosystems, as water polluted by antibiotics poses serious risks to human health and the ecological environment. Therefore, the antibiotic content in water should be identified, monitored, and eliminated. Nevertheless, there is no single method that can detect all different types of antibiotics, so various techniques are often combined to produce reliable results. This review summarizes the sources of antibiotic pollution in water, covering three main aspects: (1) wastewater discharges from domestic sewage, (2) medical wastewater, and (3) animal physiology and aquaculture. The existing analytical techniques, including extraction techniques, conventional detection methods, and biosensors, are reviewed. The electrochemical biosensors have become a research hotspot in recent years because of their rapid detection, high efficiency, and portability, and the use of nanoparticles contributes to these outstanding qualities. Additionally, the comprehensive quality evaluation of various detection methods, including the linear detection range, detection limit (LOD), and recovery rate, is discussed, and the future of this research field is also prospected.

Determination of 42 antibiotic residues in seven categories in water using large volume direct injection by ultra high performance liquid chromatography-triple quadrupole mass spectrometry

抗生素作为新型有机污染物在自然水体中被频繁检出,检出种类多且含量水平低,为了实现更加快速、全面、准确的高通量分析,研究开发了一种利用大体积直接进样测定水中7大类(磺胺类、林可酰胺类、喹诺酮类、大环内酯类、四环素类、头孢类及氯霉素类)42种抗生素的超高效液相色谱-三重四极杆质谱法。水样经0.22 μm滤膜过滤,加入Na₂EDTA并调节pH值至6.0~8.0,加入内标混匀后,采用Phenomenex Kinetex C18柱(50 mm×30 mm, 2.6 μm),以0.1%(v/v)甲酸水溶液-乙腈作为流动相进行梯度洗脱,质谱智能化分时间段-多反应选择离子监测(Schedule-MRM)模式进行检测。42种抗生素在相关线性范围内线性良好(r=0.9949~0.9995),回收率为80.1%~125%,相对标准偏差为0.8%~12.2%,方法检出限为0.015~3.561 ng/L。将该方法应用于10份水源水和5份末梢水的检测,结果显示在42种抗生素中,12种抗生素有检出,包括磺胺类、大环内酯类、林可酰胺类和氯霉素类,其在水源水中的检出率达100%;林可霉素和氯霉素是检出质量浓度最高的两种抗生素,它们的质量浓度范围分别为3.83~13.8和24.8~33.6 ng/L。该方法从检出限和回收率两方面与标准方法和文献报道进行了比较,检出限及回收率均满足要求。该方法与传统前处理方法相比具有简单、快速、绿色、精密度高、准确度高、消耗样品量小的优点,能用于地表水、地下水、末梢水等较为洁净水体中42种痕量水平的抗生素测定。

Levofloxacin Detection Using l-Cysteine Capped MgS Quantum Dots via the Photoinduced Electron Transfer Process

Antibiotics resistance is becoming one of the biggest problems of the 21st century. The prior detection of antibiotics resistance can help human beings in better treatment of diseases. Here, we have used l-Cysteine capped magnesium sulfide quantum dots (L-Cyst-MgS QDs) to detect Levofloxacin antibiotic. L-Cyst-MgS QDs were synthesized using the hydrothermal method. Transmission electron microscopy study showed monodispersed L-Cyst-MgS QDs of 2–4 nm in size. Energy dispersive x-ray photoemission spectroscopy study confirmed the elemental composition of the L-Cyst-MgS QDs without any impurity. UV-vis absorption study showed a peak centered around 340 nm. The photoluminescence study exhibited the maximum peak at 410 nm for 340 nm of excitation wavelength. L-Cyst-MgS QDs were studied with thirteen antibiotics, namely Thiamphenicol, Gentamicin, Erythromycin, Ofloxacin, Ampicillin, Ciprofloxacin, Tetracycline, Chloramphenicol, Florfenicol, Amoxicillin, Moxifloxacin, Norfloxacin, and Levofloxacin. Among these, Levofloxacin showed the most significant change in the peaks’ intensity and was further used for the interaction study. In the interaction study, the peak corresponding to MgS showed a continuous decrease, while the peak corresponding to Levofloxacin showed an increase with the increased concentrations (0–100 μg/ml) of Levofloxacin. Linear behavior was obtained in the range of 1–90 μg/ml. FT-IR study confirmed the interaction of the Levofloxacin with L-Cyst-MgS QDs. The Time-resolved fluorescence spectroscopy showed identical lifetime for both the samples and no spectral overlap confirm the FRET free system. The underlying mechanism is explained based on the electron transfer from the conduction band of the L-Cyst-MgS QDs to the HOMO of Levofloxacin. The limit of detection was found to be 0.21 μg/ml.

Overview of Sample Preparation and Chromatographic Methods to Analysis Pharmaceutical Active Compounds in Waters Matrices

In the environment, pharmaceutical residues are a field of particular interest due to the adverse effects to either human health or aquatic and soil environment. Because of the diversity of these compounds, at least 3000 substances were identified and categorized into 49 different therapeutic classes, and several actions are urgently required at multiple steps, the main ones: (i) occurrence studies of pharmaceutical active compounds (PhACs) in the water cycle; (ii) the analysis of the potential impact of their introduction into the aquatic environment; (iii) the removal/degradation of the pharmaceutical compounds; and, (iv) the development of more sensible and selective analytical methods to their monitorization. This review aims to present the current state-of-the-art sample preparation methods and chromatographic analysis applied to the study of PhACs in water matrices by pinpointing their advantages and drawbacks. Because it is almost impossible to be comprehensive in all PhACs, instruments, extraction techniques, and applications, this overview focuses on works that were published in the last ten years, mainly those applicable to water matrices.

A review of pretreatment and analysis of macrolides in food (Update Since 2010)

Macrolides are versatile broad-spectrum antibiotics whose activity stems from the presence of a macrolide ring. They are widely used in veterinary medicine to prevent and treat disease. However, because of their improper use and the absence of effective regulation, these compounds pose a threat to human health and the environment. Consequently, simple, quick, economical, and effective techniques are required to analyze macrolides in animal-derived foods, biological samples, and environmental samples. This paper presents a comprehensive overview of the pretreatment and analytical methods used for macrolides in various sample matrices, focusing on the developments since 2010. Pretreatment methods mainly include liquid-liquid extraction, solid-phase extraction, matrix solid-phase dispersion, and microextraction methods. Detection and quantification methods mainly include liquid chromatography (coupled to mass spectrometry or other detectors), electrochemical methods, capillary electrophoresis, and immunoassays. Furthermore, a comparison between the pros and cons of these methods and prospects for future developments are also discussed.

Targeted analysis of six emerging derivatives or metabolites together with 25 common macrolides in milk using Quick, Easy, Cheap, Effective, Rugged and Safe extraction and ultra-performance liquid chromatography quadrupole/electrostaticfield orbitrap mass spectrometry

An analytical method for the determination of six emerging derivatives or metabolites together with 25 common macrolides antibiotics in milk by ultra-performance liquid chromatography quadrupole/electrostaticfield orbitrap mass spectrometry was established. The samples were purified with optimized Quick, Easy, Cheap, Effective, Rugged, Safe methods. The amounts of primary-secondary amine, C18, and sodium acetate adsorbent materials were optimized by response surface method to obtain the best purification effect. The chromatographic separation was carried out using the XBridge-C18 (2.1 × 100 mm, 3.5 µm, Waters) column with mobile phase of acetonitrile with 0.1% v/v formic acid-water solutions (containing 10 mmol/L ammonium acetate), separated by gradient elution. The instrument was operated in the detection mode of electrospray positive and negative ions with Full MS/data dependent MS² acquisition mode detection, external standard method was used for quantitative analysis. The limits of detection and limits of quantitation of 31 compounds were 0.1-0.5 µg/L and 0.5-2.0 µg/L, respectively. A total of 31 compounds performed a good linearity in the range of 1 to 200 µg/L, and the correlation coefficient was greater than 0.990. The spiked recoveries in milk samples were 81.07-110.1% and the relative standard deviation was less than 5.1%. The method was successful applied to actual sample testing in the market.

Occurrence, fate and environmental risk assessment of the organic microcontaminants included in the Watch Lists set by EU Decisions 2015/495 and 2018/840 in the groundwater of Spain

This paper aims to review the existing occurrence data in Spanish groundwater (GW) for the emerging organic contaminants (EOCs) defined in the surface water Watch Lists of Decisions 2015/495/EU and 2018/840/EU since these contaminants are likely to reach GW bodies because surface waters show close interaction with GW. These two lists include 20 substances: 9 pesticides (5 neonicotinoids, 2 carbamates, 1 oxadiazole and 1 semicarbazone), 6 pharmaceuticals (diclofenac and 5 antibiotics), 3 estrogens, 1 UV filter (2-ethylhexyl-4-methoxycinnamate, EHMC) and 1 antioxidant (2,6-di-tert-butyl-4-methylphenol, BHT). Most of these substances are usually detected at low ng/L concentration range or not detected in the GW bodies of Spain. However, eventually they are reported at concentrations>100ng/L (e.g., imidacloprid, methiocarb, diclofenac, macrolide antibiotics, ciprofloxacin, EHMC and BHT). Consequently, it is required to set up drinking water standards, and/or GW threshold quality values because GW is a valuable water resource worldwide. Overall, GW is less contaminated than other water bodies, such as rivers, suggesting that aquifers possess a natural attenuation capacity and/or are less vulnerable than rivers to contamination. Nevertheless, the natural hydrogeochemical processes that control the fate and transformation of these substances during infiltration and in the aquifer have been barely investigated so far. The concentrations of the target EOCs are used to calculate hazard quotients (HQs) in the Spanish GW bodies as an estimation of their ecotoxicity and in order to compare somehow their chemical quality with respect to those of surface water. Due to the limited ecotoxicity data for most EOCs, HQs can only be calculated for few substances. The results pointed out the risk posed by the anti-inflammatory diclofenac towards Ceriodaphnia dubia (HQ=21) and the medium risk associated to the antibiotic erythromycin for Brachionus calyciflorus (HQ=0.46).

Impact of erythromycin on a non-target organism: Cellular effects on the freshwater microalga Pseudokirchneriella subcapitata

The increasing and indiscriminate use of antibiotics is the origin of their introduction in aquatic systems through domestic and livestock effluents. The occurrence of erythromycin (ERY), a macrolide antibiotic, in water bodies raises serious concerns about its potential toxic effect in aquatic biota (non-target organisms), particularly in microalgae, the first organisms in contact with aquatic contaminants. This study aimed to evaluate the possible toxic effects of ERY on relevant cell targets of the freshwater microalga Pseudokirchneriella subcapitata. Algal cells incubated with significant environmental ERY concentrations presented disturbance of the photosynthetic apparatus (increased algal autofluorescence and reduction of chlorophyll a content) and mitochondrial function (hyperpolarization of mitochondrial membrane). These perturbations can apparently be attributed to the similarity of the translational machinery of these organelles (chloroplasts and mitochondria) with the prokaryotic cells. P. subcapitata cells treated with ERY showed a modification of metabolic activity (increased esterase activity) and redox state (alteration of intracellular levels of reactive oxygen species and reduced glutathione content) and an increased biovolume. ERY induced an algistatic effect: reduction of growth rate without loss of cell viability (plasma membrane integrity). The present study shows that chronic exposure (72 h), at low (μg L^-1) ERY concentrations (within the range of concentrations detected in surface and ground waters), induce disturbances in the physiological state of the alga P. subcapitata. Additionally, this work alerts to the possible negative impact of the uncontrolled use of ERY on the aquatic systems.

Assessment of toxic effects of the antibiotic erythromycin on the marine fish gilthead seabream (Sparus aurata L.) by a multi-biomarker approach

Erythromycin (ERY) is one of the most common antibiotics used in human and veterinary practices, leading to ubiquitous environmental distribution and possible toxicity to non-target organisms. The purpose of this study was to determine sub-lethal effects of ERY towards the marine fish Sparus aurata (gilthead seabream). S. aurata were acutely (0.3-323 μg/L, 96 h) and chronically (0.7-8.8 μg/L, 28 d) exposed to ERY. Detoxification [7-ethoxyresorufin O-deethylase (EROD), glutathione S-transferases (GSTs), uridine-diphosphate-glucuronosyltransferase (UGT)], oxidative stress [catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GRed)], lipid peroxidation [thiobarbituric acid reactive substances - (TBARS)], genotoxicity [genetic damage index (GDI) and erythrocytic nuclear abnormalities (ENAs)], neurotransmission [acetylcholinesterase (AChE)] and energy metabolism [lactate dehydrogenase (LDH)] biomarkers were evaluated. Results showed that ERY did not promote significant effects in detoxification biomarkers, but induced slight pro-oxidative effects (decrease of GPx activity in the liver after acute exposure and an increase in gills after chronic exposure; and an increase of hepatic GRed activity following chronic exposure). There was a significant decrease in TBARS after chronic exposure, which contradicts a full scenario of oxidative stress. In terms of genotoxicity, both ERY exposures caused only a significant increase of GDI. Neurotransmission and energy metabolism were not also affected by ERY. Although few toxic effects of ERY have been previously documented (involving different metabolic pathways, as tested in this work), these were mainly observed for freshwater species. These findings suggest low vulnerability of S. aurata to ERY at levels close to the ones found in the wild.

Toxicity of erythromycin to Oncorhynchus mykiss at different biochemical levels: detoxification metabolism, energetic balance, and neurological impairment

During the last decades, the presence of antibiotics in different aquatic compartments has raised increasing interest and concern, since these compounds are usually persistent and bioactive pseudo pollutants. Erythromycin (ERY) is a macrolide antibiotic, prescribed for human and veterinary medicines but also used in aquaculture and livestock production. Taking into account the recorded environmental levels of ERY, its toxicity to non-target organisms has become a still poorly studied issue, particularly in fish. In this sense, this study investigated the acute and chronic effects of realistic levels of ERY on Oncorhynchus mykiss (rainbow trout), namely, through the quantification of the activity of enzymes involved in different biochemical pathways, such as detoxification (phase I-7-ethoxyresorufin O-deethylase (EROD); phase II-glutathione S-transferases (GSTs), uridine-diphosphate-glucuronosyltransferases (UGTs)), neurotransmission (acetylcholinesterase (AChE)), and energy production (lactate dehydrogenase (LDH)). Both types of exposure caused significant increases in EROD activity in liver of O. mykiss; an increase in GST activity in gills after chronic exposure was also observed. UGT branchial activity was significantly depressed, following the long-term exposure. Thus, EROD, GST, and UGT enzymatic forms seem to be involved in the biotransformation of ERY. In terms of neurotransmission and preferential pathway of energy homeostasis, the exposed organisms appear not to have been affected, as there were no significant alterations in terms of AChE and LDH activities, respectively. The here-obtained data suggest that the observed alterations in terms of detoxification enzymes may have prevented the establishment of a set of toxic responses, namely, neurotoxic and metabolic disorders.

Cellular metabolism network of Bacillus thuringiensis related to erythromycin stress and degradation

Erythromycin is one of the most widely used macrolide antibiotics. To present a system-level understanding of erythromycin stress and degradation, proteome, phospholipids and membrane potentials were investigated after the erythromycin degradation. Bacillus thuringiensis could effectively remove 77% and degrade 53% of 1 µM erythromycin within 24 h. The 36 up-regulated and 22 down-regulated proteins were mainly involved in spore germination, chaperone and nucleic acid binding. Up-regulated ribose-phosphate pyrophosphokinase and ribosomal proteins confirmed that the synthesis of protein, DNA and RNA were enhanced after the erythromycin degradation. The reaction network of glycolysis/gluconeogenesis was activated, whereas, the activity of spore germination was decreased. The increased synthesis of phospholipids, especially, palmitoleic acid and oleic acid, altered the membrane permeability for erythromycin transport. Ribose-phosphate pyrophosphokinase and palmitoleic acid could be biomarkers to reflect erythromycin exposure. Lipids, disease, pyruvate metabolism and citrate cycle in human cells could be the target pathways influenced by erythromycin. The findings presented novel insights to the interaction among erythromycin stress, protein interaction and metabolism network, and provided a useful protocol for investigating cellular metabolism responses under pollutant stress.

Determination of Ten Macrolide Drugs in Environmental Water Using Molecularly Imprinted Solid-Phase Extraction Coupled with Liquid Chromatography-Tandem Mass Spectrometry

With the extensive application of antibiotics in livestock, their contamination of the aquatic environment has received more attention. Molecularly imprinted polymer (MIP), as an eco-friendly and durable solid-phase extraction material, has shown great potential for the separation and enrichment of antibiotics in water. This study aims at developing a practical and economical method based on molecularly imprinted solid phase extraction (MISPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for simultaneously detecting ten macrolide drugs in different sources of water samples. The MIP was synthesized by bulk polymerization using tylosin as the template and methacrylic acid as the functional monomer. The MIP exhibited a favorable load-bearing capacity for water (>90 mL), which is more than triple that of non-molecularly imprinted polymers (NIP). The mean recoveries of macrolides at four spiked concentration levels (limit of quantification, 40, 100, and 400 ng/L) were 62.6–100.9%, with intra-day and inter-day relative standard deviations below 12.6%. The limit of detection and limit of quantification were 1.0–15.0 ng/L and 3.0–40.0 ng/L, respectively. Finally, the proposed method was successfully applied to the analysis of real water samples.

Detection of Antibiotics and Evaluation of Antibacterial Activity with Screen-Printed Electrodes

This review provides a brief overview of the fabrication and properties of screen-printed electrodes and details the different opportunities to apply them for the detection of antibiotics, detection of bacteria and antibiotic susceptibility. Among the alternative approaches to costly chromatographic or ELISA methods for antibiotics detection and to lengthy culture methods for bacteria detection, electrochemical biosensors based on screen-printed electrodes present some distinctive advantages. Chemical and (bio)sensors for the detection of antibiotics and assays coupling detection with screen-printed electrodes with immunomagnetic separation are described. With regards to detection of bacteria, the emphasis is placed on applications targeting viable bacterial cells. While the electrochemical sensors and biosensors face many challenges before replacing standard analysis methods, the potential of screen-printed electrodes is increasingly exploited and more applications are anticipated to advance towards commercial analytical tools.