Mercury immunotoxicity in the brown watersnake (Nerodia taxispilota): An in vitro study.

Mercury (Hg) is a heavy metal that enters the environment through natural and anthropogenic means. Once in the environment, Hg can biomagnify in food webs and is known to cause immunotoxic effects to wildlife. Compared with other vertebrates, knowledge of the reptilian immune system is lacking, especially in snakes. Further, even less is known about the impact of environmental contaminants on snake immunity. This gap in knowledge is largely due to an absence of established immune-based assays or specific reagents for these species. In this study, brown watersnakes (Nerodia taxispilota; n = 23) were captured on the Savannah River (Augusta, Georgia, USA), weighed, measured, bled, and released. Peripheral blood leukocytes (24 h old) were enriched and evaluated with an established mammalian in vitro lymphocyte proliferation assay. Enriched leukocytes were then exposed to mercury chloride (HgCl2 ) at 3.75, 37.5, and 75 µM. Total mercury (THg) in whole blood was also quantified. Snake peripheral blood leukocyte enrichment yielded >90% lymphocytes with viabilities averaging >70%. Exposure to HgCl2 resulted in significant dose-dependent suppression of proliferative responses relative to spontaneous proliferation at 37.5 and 75 µM (both p ≤ 0.01) but not 3.75 µM (p = 0.99). Mean ± 1 SE concentration of THg in whole blood was 0.127 ± 0.027 mg/kg (wet weight). Based on the in vitro findings with HgCl2 , snakes in systems with heavy Hg pollution may be at risk of immunosuppression, but N. taxispilota at the site in this study appear to be at low risk.

Acetylcholinesterase (AChE) monoclonal antibody generation and validation for use as a biomarker of glyphosate-based herbicide exposure in commercial freshwater fish.

Monoclonal antibody specific to acetylcholinesterase (AChE) was extracted from the brain of hybrid catfish after exposure to glyphosate-based herbicide for 24 h. AChE was partially purified using hydroxyapatite and chromatography columns. The specific characteristics of AChE were studied by western blot using commercial polyclonal antibody (Rabbit anti-Fish AChE). It was found that the protein band had a molecular weight of 71 kDa. After mice were injected with AChE 4 times, the spleen showed a response to the induction. Polyclonal B cells from the mouse's spleen were taken and fused with myeloma cells to produce hybrid cells. After two fusions were performed, the clones specific to AChE were selected by dot blot, ELISA, immunohistochemistry and western blot techniques. Two clones, ACHE 33 and ACHE 99, which had the isotype of IgM were found. These two produced monoclonal antibodies specific to AChE in both denatured and native forms. The ACHE 33 monoclonal antibody clone from hybrid catfish could be cross-react with two commercial freshwater fishes, Nile tilapia and climbing perch, based on dot blot, immunohistochemistry, and western blot techniques. Moreover, AChE in Nile tilapia and climbing perch with glyphosate- based herbicide exposure gave a positive result with ACHE 33 as protein with molecular weight of 66 kDa. Based on our results, the produced monoclonal antibody showed specificity and could be applied to test AChE expression to assess glyphosate-based herbicide contamination in hybrid catfish, Nile tilapia and climbing perch. It could be also be a useful tool in indicating the quality of water resources.

Direct competitive immunosensor for Imidacloprid pesticide detection on gold nanoparticle-modified electrodes.

A direct competitive immunosensor for the electrochemical determination of Imidacloprid (IMD) pesticide on gold nanoparticle-modified screen-printed carbon electrodes (AuNP-SPCE) is here reported for the first time. Self-obtained specific monoclonal antibodies are immobilized on the AuNP-SPCE taking advantage of the AuNPs biofunctionalization abilities. In our biosensor design, free IMD in the sample competes with IMD conjugated with horseradish peroxidase (IMD-HRP) for the recognition by the antibodies. After that, 3,3',5,5'-Tetramethylbenzidine (TMB) is enzymatically oxidized by HRP, followed by the oxidized TMB reduction back at the surface of the SPCE. This process gives an associated catalytic current (analytical signal) that is inversely proportional to the IMD amount. The main parameters affecting the analytical signal have been optimized, reaching a good precision (repeatability with a RSD of 6%), accuracy (relative error of 6%), stability (up to one month), selectivity and an excellent limit of detection (LOD of 22 pmol L-1), below the maximum levels allowed by the legislation, with a wide response range (50-10000 pmol L-1). The detection through antibodies also allows to have an excellent selectivity against other pesticides potentially present in real samples. Low matrix effects were found when analysing IMD in tap water and watermelon samples. The electrochemical immunosensor was also validated with HPLC-MS/MS, the reference method used in official laboratories for IMD analysis, through statistical tests. Our findings make the electrochemical immunosensor as an outstanding method for the rapid and sensitive determination of IMD at the point-of-use.

Construction of Immunomagnetic Particles with High Stability in Stringent Conditions by Site-Directed Immobilization of Multivalent Nanobodies onto Bacterial Magnetic Particles for the Environmental Detection of Tetrabromobisphenol-A.

Bacterial magnetic particles (BMPs) are an attractive carrier material for immunoassays because of their nanoscale size, dispersal ability, and membrane-bound structure. Antitetrabromobisphenol-A (TBBPA) nanobodies (Nbs) in the form of monovalence (Nb1), bivalence (Nb2), and trivalence (Nb3) were biotinylated and immobilized onto streptavidin (SA)-derivatized BMPs to construct the complexes of BMP-SA-Biotin-Nb1, -Nb2, and -Nb3, respectively. An increasing order of binding capability of BMP-SA-Biotin-Nb1, -Nb2, and -Nb3 to TBBPA was observed. These complexes showed high resilience to temperature (90 °C), methanol (100%), high pH (12), and strong ionic strength (1.37 M NaCl). A BMP-SA-Biotin-Nb3-based enzyme linked immunosorbent assay (ELISA) for TBBPA dissolved in methanol was developed, showing a half-maximum inhibition concentration (IC50) of 0.42 ng mL-1. TBBPA residues in landfill leachate, sewage, and sludge samples determined by this assay were in a range of

Colorimetric bio-barcode immunoassay for parathion based on amplification by using platinum nanoparticles acting as a nanozyme.

A competitive bio-barcode immunoassay is described for the trace detection of parathion in water, pear, cabbage, and rice samples. It is based on amplification by platinum nanoparticle acting as a nanozyme. Gold nanoparticles (AuNPs) were modified with (a) monoclonal antibodies (mAbs) against parathion, and (b) thiolated single-stranded DNA (ssDNA) oligonucleotides. Magnetic nanoparticles (MNPs) were functionalized with ovalbumin coupled with parathion hapten. Parathion and its hapten compete with mAbs on the surface of the AuNPs. Subsequently, the platinum nanoparticles (PtNPs) probe, which was functionalized with the complementary thiolated ssDNA (C-ssDNA), was added to the reaction mixture for the detection of parathion. The signal was catalytically amplified by coupling with platinum nanozyme using teramethylbenzidine and H2O2 as the chromogenic system. The immunoassay has a linear range that extends from 0.01-50 µg·L-1, and the limit of detection is 2.0 × 10-3 µg·L-1. The recoveries and relative standard deviations (RSDs) ranged from 91.1-114.4% and 3.6-15.8%, respectively. The method correlates well with data obtained by gas chromatography-tandem mass spectrometry (GC-MS/MS). Graphical abstract The parathion and the magnetic nanoparticles (MNPs) labelled with hapten-OVA competitively reacted to AuNPs modified with mAbs and thiolated DNA for the detection of parathion. The signal was catalyzed by platinum nanozyme. The limit of detection for parathion is 2.0 ng·L-1.

Immune response of juvenile common carp (Cyprinus carpio L.) exposed to a mixture of sewage chemicals.

Pharmaceuticals and household chemicals are important components of municipal sewage. Many of them are biologically active, disrupting not only hormonal regulation of aquatic animals but also, indirectly, disturbing their immunological protection. In the environment, chemicals rarely act as individual substances, but as elements of mixtures. Therefore, the aim of this study was to check whether the acute laboratory exposure of common carp juveniles to a mixture of ibuprofen, sodium dodecyl sulphate (SDS), dimethyl sulfoxide (DMSO) and 17 α-ethynylestradiol in increasing concentrations, modifies the levels of innate immunity (lysozyme, C-reactive protein) as well as general stress (metallothioneins, heat shock proteins HSP70) markers in brain, liver, gills, spleen and mucus. The levels of the markers were measured by an immunodetection technique. Not only do the pharmaceuticals and household chemicals impair immunological reactions of young carp in various tissues but also do that in a concentration-dependent manner in the liver, gills, spleen and mucus. This has a very important implication, since it may result in higher sensitivity of young fish to pathogens due to energy allocation to defence processes. The comparisons of the pattern of stress reactions in the studied organ samples indicated that mucus appeared to be a good, non-invasive material for monitoring of environmental state and fish conditions.

An Anticaffeine Antibody-Oligonucleotide Conjugate for DNA-Directed Immobilization in Environmental Immunoarrays.

The development of fast and cheap high-throughput platforms for the detection of environmental contaminants is of particular importance to understand the human-related impact on the environment. The application of DNA-directed immobilization (DDI) of IgG molecules is currently limited to the clinical diagnostics scenario, possibly because of the high costs of production of such addressable platforms. We here describe the efficient and specific hybridization of an antibody-oligonucleotide conjugate to a short 12-mer capture probe. The specific antibody used is a monoclonal antibody against caffeine, a stimulant and important anthropogenic marker. With this work, we hope to contribute to broadening the application potential of DDI to environmental markers in order to develop cheaper and more stable high-throughput screening platforms for standard routine analysis of pollutants in a variety of complex matrices.

Simultaneous determination of paraquat and atrazine in water samples with a white light reflectance spectroscopy biosensor.

An optical immunosensor based on White Light Reflectance Spectroscopy for the simultaneous determination of the herbicides atrazine and paraquat in drinking water samples is demonstrated. The biosensor allows for the label-free real-time monitoring of biomolecular interactions taking place onto a SiO2/Si chip by transforming the shift in the reflected interference spectrum due to reaction to effective biomolecular layer thickness. Dual-analyte determination is accomplished by functionalizing spatially distinct areas of the chip with protein conjugates of the two herbicides and scanning the surface with an optical reflection probe. A competitive immunoassay format was adopted, followed by reaction with secondary antibodies for signal enhancement. The sensor was highly sensitive with detection limits of 40 and 50 pg/mL for paraquat and atrazine, respectively, and the assay duration was 12 min. Recovery values ranging from 90.0 to 110% were determined for the two pesticides in spiked bottled and tap water samples, demonstrating the sensor accuracy. In addition, the sensor could be regenerated and re-used at least 20 times without significant effect on the assay characteristics. Its excellent analytical performance and short analysis time combined with the small sensor size should be helpful for fast on-site determinations of these analytes.

Spatial distribution variation and probabilistic risk assessment of exposure to chromium in ground water supplies; a case study in the east of Iran.

A high concentration of chromium (VI) in groundwater can threaten the health of consumers. In this study, the concentration of chromium (VI) in 18 drinking water wells in Birjand, Iran, s was investigated over a period of two yearsNon-carcinogenic risk assessment, sensitivity, and uncertainty analysis as well as the most important variables in determining the non-carcinogenic risk for three age groups including children, teens, and adults, were performed using the Monte Carlo simulations technique. The northern and southern regions of the study area had the highest and lowest chromium concentrations, respectively. The chromium concentrations in 16.66% of the samples in an area of 604.79 km2 were more than World Health Organization (WHO) guideline (0.05 mg/L). The Moran's index analysis showed that the distribution of contamination is a cluster. The Hazard Index (HI) values for the children and teens groups were 1.02 and 2.02, respectively, which was more than 1. A sensitivity analysis indicated that the most important factor in calculating the HQ was the concentration of chromium in the consumed water. HQ values higher than 1 represent a high risk for the children group, which should be controlled by removing the chromium concentration of the drinking water.

Ultrasensitive Nano-rt-iPCR for Determination of Polybrominated Diphenyl Ethers in Natural Samples.

Extensive polybrominated diphenyl ethers (PBDEs) use has resulted in its increasingly widespread presence in the environment. PBDEs release from existing products can still persist and accumulate in the environment as well as in human and wildlife magnifying through the food web. Due to its ultra-trace amount in the environment, a novel ultrasensitive nano-rt-iPCR assay has been developed to determine polybrominated diphenyl ethers in natural samples. Numerous amino-DNA and polyclonal antibody (anti-PBDE) were immobilized onto the single-walled carbon nanotubes (SWCNTs) to form antibody-SWCNTs-DNA signal amplifier used in the proposed immunoassay system. Compared with rt-iPCR, this nano-rt-iPCR assay had a higher ratio of signal DNA, which meant higher signal measured and lower detection limit. This proposed nano-rt-iPCR assay was used to determine PBDEs in water samples ranging from 0.5 pg/L to 0.5ng/L; giving the LOD 1 pg/L. To the best of our knowledge, this nano-rt-iPCR is the most sensitive method for PBDEs detection. Because of that, this method needs no pre-concentration or extractions, using sample sizes as low as 10 µL. In general, this nano-rt-iPCR method will be a useful and potential way for batch detection of ultra-trace PBDEs in the aquatic environment.

A survey of 17α-ethinylestradiol and mestranol residues in Hawkesbury River, Australia, using a highly specific enzyme-linked immunosorbent assay (ELISA) demonstrates the levels of potential biological significance.

This study reports on the potential status of 17α-ethinylestradiol (EE2) and mestranol (MeEE2) residues in aquatic environments in New South Wales (NSW), Australia, based on the analysis by a specific ELISA we developed. Polyclonal antibodies were raised against the EE2 hapten with a linker attached at the C3-position to direct the antibody binding towards the ring D of EE2/MeEE2. Using this approach, an ELISA highly specific to EE2 and MeEE2 was successfully developed, showing less than 3.1% cross-reactivity (% CR) with other major steroidal sex hormones and their derivatives. The assay performed with the limit of detection (LOD) of 0.04 ± 0.01µg/L for both EE2 and MeEE2, and the limit of quantitation (LOQ) of 0.05 ± 0.01ng/L when it was coupled with the SM2-Biobeads solid phase extraction. Prior to conducting the survey study, it was validated against the gas chromatography-mass spectrophotometry (GC-MS) method, which showed high correlation with R2 of 0.934. Fresh surface water samples collected at different sites along Hawkesbury River in New South Wales (NSW) were analyzed for the EE2/ MeEE2 residues using the developed ELISA. The EE2/MeEE2 levels were found to range between 4.1 and 8.3ng/L in Emigrant Creek, NSW, where the primary activity was macadamia plantation, and higher levels between 15 and 29ng/L in South Creek, NSW, Greater Western Sydney at sites upstream and downstream of the municipal sewage treatment plants.

Fluoride exposure abates pro-inflammatory response and induces in vivo apoptosis rendering zebrafish (Danio rerio) susceptible to bacterial infections.

The present study describes the immunotoxic effect of chronic fluoride exposure on adult zebrafish (Danio rerio). Zebrafish were exposed to fluoride (71.12 mg/L; 1/10 LC50) for 30 d and the expression of selected genes studied. We observed significant elevation in the detoxification pathway gene cyp1a suggesting chronic exposure to non-lethal concentration of fluoride is indeed toxic to fish. Fluoride mediated pro-oxidative stress is implicated with the downregulation in superoxide dismutase 1 and 2 (sod1/2) genes. Fluoride affected DNA repair machinery by abrogating the expression of the DNA repair gene rad51 and growth arrest and DNA damage inducible beta a gene gadd45ba. The upregulated expression of casp3a coupled with altered Bcl-2 associated X protein/B-cell lymphoma 2 ratio (baxa/bcl2a) clearly suggested chronic fluoride exposure induced the apoptotic cascade in zebrafish. Fluoride-exposed zebrafish when challenged with non-lethal dose of fish pathogen A. hydrophila revealed gross histopathology in spleen, bacterial persistence and significant mortality. We report that fluoride interferes with system-level output of pro-inflammatory cytokines tumour necrosis factor-α, interleukin-1ß and interferon-γ, as a consequence, bacteria replicate efficiently causing significant fish mortality. We conclude, chronic fluoride exposure impairs the redox balance, affects DNA repair machinery with pro-apoptotic implications and suppresses pro-inflammatory cytokines expression abrogating host immunity to bacterial infections.

Production of monoclonal antibodies with broad specificity and development of an immunoassay for microcystins and nodularin in water.

Microcystins (MCs) and nodularin (NOD) are cyanobacterial hepatotoxins that can greatly harm human health. Multi-analyte immunoassays provide efficient and cheap methods of screening these toxins. To develop a multi-analyte immunoassay, an antibody with both broad specificity and high affinity for structurally similar algal toxins is urgently needed. In this study, microcystin-leucine-arginine (MC-LR) and NOD were conjugated to carrier proteins using a one-step active ester (AE) method and multistep thiol-ene click chemistry and glutaraldehyde method, respectively. The immunogens obtained from these two conjugation methods were evaluated for their effectiveness in producing antibodies. The results demonstrated that the antisera derived from AE immunogens showed better performance in terms of affinity and titer. Using this simple AE method, we prepared a new immunogen for NOD and successfully produced a monoclonal antibody (mAb), 2G5, which could recognize not only NOD but also all eight of the tested MCs (MC-LR, MC-RR, MC-YR, MC-WR, MC-LA, MC-LF, MC-LY, and MC-LW) with high sensitivity and improved uniform affinities (0.23 ≤ IC50 ≤ 0.68 ng mL(-1)) compared with previously described mAbs. Under optimal conditions, one indirect competitive enzyme-linked immunosorbent assay was developed based on mAb2G5 for the detection of MC-LR and NOD, with limits of detection of 0.16 and 0.10 µg L(-1), respectively, and a recovery of 62-86 % with a coefficient of variation below 12.6 % in water samples.

Structural considerations on the selectivity of an immunoassay for sulfamethoxazole.

Sulfamethoxazole (SMX), a sulfonamide, is a widely used bacteriostatic antibiotic and therefore a promising marker for the entry of anthropogenic pollution in the environment. SMX is frequently found in wastewater and surface water. This study presents the production of high affinity and selective polyclonal antibodies for SMX and the development and evaluation of a direct competitive enzyme-linked immunosorbent assay (ELISA) for the quantification of SMX in environmental water samples. The crystal structures of the cross-reacting compounds sulfamethizole, N(4)-acetyl-SMX and succinimidyl-SMX were determined by x-ray diffraction aiming to explain their high cross-reactivity. These crystal structures are described for the first time. The quantification range of the ELISA is 0.82-63µg/L. To verify our results, the SMX concentration in 20 environmental samples, including wastewater and surface water, was determined by ELISA and tandem mass spectrometry (MS/MS). A good agreement of the measured SMX concentrations was found with average recoveries of 97-113% for the results of ELISA compared to LC-MS/MS.

Multi-channeled single chain variable fragment (scFv) based microfluidic device for explosives detection.

The development of explosives detection technologies has increased significantly over the years as environmental and national security agencies implement tighter pollution control measures and methods for improving homeland security. 2, 4, 6-Trinitrotoluene (TNT), known primarily as a component in munitions, has been targeted for both its toxicity and carcinogenic properties that if present at high concentrations can be a detriment to both humans, marine and plant ecosystems. Enabling end users with environmental detection and monitoring systems capable of providing real-time, qualitative and quantitative chemical analysis of these toxic compounds would be extremely beneficial. Reported herein is the development of a multi-channeled microfluidic device immobilized with single chain fragment variable (scFv) recombinant proteins specific for the explosive, TNT. Fluorescence displacement immunoassays performed under constant flow demonstrated trace level sensitivity and specificity for TNT. The utility of three multi-channeled devices immobilized with either (1) scFv recombinant protein, (2) biotinylated-scFv (bt-scFv) and (3) monoclonal anti-TNT (whole IgG molecule) were investigated and compared. Fluorescence dose response curves, crossreactivity measurements and limits of detection (LOD) for TNT were determined. Fluorescence displacement immunoassays for TNT in natural seawater demonstrated detection limits at sub-parts-per-billion levels (0.5 ppb) utilizing the microfluidic device with immobilized bt-scFv.

Detection of the carcinogenic water pollutant benzo[a]pyrene with an electro-switchable biosurface.

The toxic nature of polycyclic aromatic hydrocarbons (PAHs), in particular benzo[a]pyrene (B[a]P), neccessitates the monitoring of PAH contamination levels in food and the environment. Here we introduce an indirect immunoassay format using electro-switchable biosurfaces (ESB) for the detection of B[a]P in water. The association of anti-B[a]P antibodies to microelectrodes is analyzed in real-time by measuring changes in the oscillation dynamics of DNA nanolever probes, which are driven to switch their orientations by high-frequency electrical actuation. From the association kinetics, the active concentration of anti-B[a]P, and hence the B[a]P contamination of the sample, can be determined with picomolar sensitivity. The detection limit of the assay improves with measurement time because increasingly accurate analyses of the binding kinetics become possible. It is demonstrated that an exceedance of the permissible 10 ng/L (40 pM) limit for B[a]P is detectable in an unprecedented short assay time (<1 h), using a simple three-step workflow involving minimal sample preparation. The reproducibility was satisfying with standard deviations below 5%. Further, the utility of the assay for practical applications is exemplified by analyzing a river water sample.

Group determination of 14-membered macrolide antibiotics and azithromycin using antibodies against common epitopes.

Erythromycin (ERY), clarithromycin (CLA), roxithromycin (ROX), and azithromycin (AZI) are macrolide antibiotics widely used in livestock and human medicine. Therefore, they are frequently found as pollutants in environmental water. A method based on indirect competitive enzyme-linked immunosorbent assay (ELISA) for group determination of these macrolides in foodstuffs, human biofluids, and water was developed. Carboxymethyloxime of clarithromycin (CMO-CLA) was synthesized and conjugated to bovine serum albumin (BSA) and gelatin to prepare immunogen and coating antigen with advantageous presentation of target epitopes, l-cladinose and d-desosamine, common for these analytes. Antibodies generated in rabbits were capable of recognizing ERY, CLA, and ROX as a group (100-150%), and AZI (12%) and did not cross-react with ERY degradants, which lack antibiotic activity. Assay displayed sensitivity of determination of 14-membered macrolides (IC50=0.13-0.2ng/ml) and low limit of detection (LOD) that was achieved at 0.02 to 0.03ng/ml. It allowed performing analysis of milk, muscle, eggs, bovine serum, water, human serum and urine, and avoiding matrix effect without special pretreatment using simple dilution with assay buffer. For 15-membered macrolide AZI, the corresponding characteristics were IC50=1.6ng/ml and LOD=0.14ng/ml. The recoveries of veterinary and human medicine macrolides from corresponding matrices were validated and found to be satisfactory.

Love wave immunosensor for the detection of carbaryl pesticide.

A Love Wave (LW) immunosensor was developed for the detection of carbaryl pesticide. The experimental setup consisted on: a compact electronic characterization circuit based on phase and amplitude detection at constant frequency; an automated flow injection system; a thermal control unit; a custom-made flow-through cell; and Quartz /SiO2 LW sensors with a 40 µm wavelength and 120 MHz center frequency. The carbaryl detection was based on a competitive immunoassay format using LIB-CNH45 monoclonal antibody (MAb). Bovine Serum Albumin-CNH (BSA-CNH) carbaryl hapten-conjugate was covalently immobilized, via mercaptohexadecanoic acid self-assembled monolayer (SAM), onto the gold sensing area of the LW sensors. This immobilization allowed the reusability of the sensor for at least 70 assays without significant signal losses. The LW immunosensor showed a limit of detection (LOD) of 0.09 µg/L, a sensitivity of 0.31 µg/L and a linear working range of 0.14-1.63 µg/L. In comparison to other carbaryl immunosensors, the LW immunosensor achieved a high sensitivity and a low LOD. These features turn the LW immunosensor into a promising tool for applications that demand a high resolution, such as for the detection of pesticides in drinking water at European regulatory levels.

New competitive dendrimer-based and highly selective immunosensor for determination of atrazine in environmental, feed and food samples: the importance of antibody selectivity for discrimination among related triazinic metabolites.

A new voltammetric competitive immunosensor selective for atrazine, based on the immobilization of a conjugate atrazine-bovine serum albumine on a nanostructured gold substrate previously functionalized with poliamidoaminic dendrimers, was realized, characterized, and validated in different real samples of environmental and food concern. Response of the sensor was reliable, highly selective and suitable for the detection and quantification of atrazine at trace levels in complex matrices such as territorial waters, corn-cultivated soils, corn-containing poultry and bovine feeds and corn flakes for human use. Selectivity studies were focused on desethylatrazine, the principal metabolite generated by long-term microbiological degradation of atrazine, terbutylazine-2-hydroxy and simazine as potential interferents. The response of the developed immunosensor for atrazine was explored over the 10(-2)-10(3) ng mL(-1) range. Good sensitivity was proved, as limit of detection and limit of quantitation of 1.2 and 5 ng mL(-1), respectively, were estimated for atrazine. RSD values <5% over the entire explored range attested a good precision of the device.