Rapid Detection Of Contaminants Research Articles

Metal-Organic Frameworks Based Sensor Platforms for Rapid Detection of Contaminants in Wastewater.

Metal-organic frameworks (MOFs) are a type of multifunctional material with organic-inorganic doped metal complexes that have a lot of unsaturated metal sites and a consistent network structure. MOFs work has great performance for enhancing the mass transfer, signal, and sensitivity as well as analyte enrichment. This study highlights the recent advancements of MOFs-based sensors for pollutant detection in a water environment and summarizes the effect of various synthetic materials on the performance of MOFs-based sensors. The related challenges and optimization techniques have been discussed. Then the research results of various MOFs sensors in the detection of wastewater pollutants are analyzed. Finally, the challenges facing MOFs-based water sensor development and the outlook for future research are discussed.

Deep Learning-Based Multicapturer SERS Platform on Plasmonic Nanocube Metasurfaces for Multiplex Detection of Organophosphorus Pesticides in Environmental Water.

In situ rapid detection of contaminants in environmental water is crucial for protecting the ecological environment and human health; however, it is always hindered by the complexity of sample matrices, trace content, and unknown species. Herein, we demonstrate a deep learning-based multicapturer surface-enhanced Raman scattering (SERS) platform on plasmonic nanocube metasurfaces for multiplex determination of organophosphorus pesticides (OPPs) residues. Poly(vinylpyrrolidone), 4-mercaptobenzoic acid, and l-cysteine are assembled on Ag nanocubes (AgNCs) and act as capturers to chemically define OPPs. Meanwhile, the OPPs-captured AgNCs efficiently close the interparticle distance and generate plasmonic metasurfaces, guaranteeing ultrasensitive and reproducible SERS analysis. Furthermore, by strategically combining all capturer-OPP SERS spectra, comprehensive "combined-SERS spectra" are reconstructed to enhance spectral variations of each OPP. Based on the combined-SERS spectra, a deep learning model is trained to predict OPPs, which significantly improve the qualitative and quantitative analysis accuracy. We successfully identified multiple OPPs in farmland, river, and fishpond water using this strategy. The whole detection procedure requires only 30 min, including sampling, SERS measurements, and deep learning analyses. This combination of a multicapturer SERS platform with the deep learning algorithm creates a rapid and reliable analytical strategy for multiplex detection of target molecules, providing a potential paradigm shift for environment-related research.

Label-Free Fluorescence Sensing Strategy Based on Functional Nucleic Acids via Energy Transfer between DNA-Templated Silver Nanoclusters and Gold Nanorods.

A simple and low-cost fluorescence signal-on sensing strategy has been developed based on functional nucleic acids (FNAs) via energy transfer between DNA-templated silver nanoclusters (DNA-AgNCs) and gold nanorods (GNRs). FNAs were used as highly selective recognition probes, in which an aptamer was used to detect small molecules represented by tetracycline, and DNAzyme was used to detect heavy metal ions represented by Pb2+. The fluorescent DNA-AgNCs were synthesized by the designed oligonucleotide sequences, which consisted of three parts: AgNCs synthesis template C6G5C6, spacer T5, and complementary sequences of the aptamer or enzyme strand. The difference in electrostatic interactions between ss/dsDNA and positively charged GNRs leads to energy transfer with different efficiencies. The analytes represented by tetracycline and Pb2+ can destroy the dsDNA structure and reduce the energy-transfer efficiency between DNA-AgNCs and GNRs, thus achieving fluorescence recovery and a signal-on analytical strategy. This strategy has excellent specificity and sensitivity with limit of detections of 4.411 nM for tetracycline and 1.416 nM for Pb2+ and has been successfully applied to detect tetracycline in milk and Pb2+ in river water. Using DNA-AgNCs formed in situ as signal probes, this strategy does not require labels or modifications and can be completed without complex analytical instruments. Moreover, this strategy can be extended to detect other targets by replacing FNA sequences. Therefore, it has promising prospects in the sensitive, simple, and rapid detection of contaminants in food and environment samples.

Rolling Circle Amplification as an Efficient Analytical Tool for Rapid Detection of Contaminants in Aqueous Environments.

Environmental contaminants are a global concern, and an effective strategy for remediation is to develop a rapid, on-site, and affordable monitoring method. However, this remains challenging, especially with regard to the detection of various contaminants in complex water environments. The application of molecular methods has recently attracted increasing attention; for example, rolling circle amplification (RCA) is an isothermal enzymatic process in which a short nucleic acid primer is amplified to form a long single-stranded nucleic acid using a circular template and special nucleic acid polymerases. Furthermore, this approach can be further engineered into a device for point-of-need monitoring of environmental pollutants. In this paper, we describe the fundamental principles of RCA and the advantages and disadvantages of RCA assays. Then, we discuss the recently developed RCA-based tools for environmental analysis to determine various targets, including heavy metals, organic small molecules, nucleic acids, peptides, proteins, and even microorganisms in aqueous environments. Finally, we summarize the challenges and outline strategies for the advancement of this technique for application in contaminant monitoring.

Rapid detection of contamination of objects and water surfaces by aggressive chemicals and uranium compounds

In response to the deteriorating environmental situation, timely and rapid detection of environmental pollutants by aggressive chemicals is important for protection measures. Thousands of tons of aggressive chemicals and waste from the nuclear industry are transported by rail and road every day. In order to quickly detect the straits, when these substances are scattered, it is necessary to have the means of their rapid detection. This article describes a portable chemical express laboratory for the rapid resolution of these problems. The laboratory consists of two unified cases with aerosol devices placed in them. In the first case are aerosol devices to detect aggressive chemicals of acidic, alkaline, and oxidative nature, and derivatives of rocket fuel dimethylhydrazin. This set of cases allows detecting almost all types of aggressive chemicals. In the second case are aerosol devices to detect both radioactive and low-radioactive uranium compounds present in radioactive waste, which also allows controlling the leakage of spent nuclear fuel.

Environment and food safety: a novel integrative review.

Environment protection and food safety are two critical issues in the world. In this review, a novel approach which integrates statistical study and subjective discussion was adopted to review recent advances on environment and food safety. Firstly, a scientometric-based statistical study was conducted based on 4904 publications collected from the Web of Science Core Collection database. It was found that the research on environment and food safety was growing steadily from 2001 to 2020. Interestingly, the statistical analysis of most-cited papers, titles, abstracts, keywords, and research areas revealed that the research on environment and food safety was diverse and multidisciplinary. In addition to the scientometric study, strategies to protect environment and ensure food safety were critically discussed, followed by a discussion on the emerging research topics, including emerging contaminates (e.g., microplastics), rapid detection of contaminants (e.g., biosensors), and environment friendly food packaging materials (e.g., biodegradable polymers). Finally, current challenges and future research directions were proposed.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-021-16069-6.

Rapid Contamination Detection in Validamycin A Production by HS-SPME/GC-MS

Background: Validamycin A (Val-A) is one of the most widely used agricultural antibiotics in East Asia especially for controlling rice sheath blight disease. Fermentation contamination of the industrial Val-A producing strain is a common occurrence. Methods: Fermentation culture of S. hygroscopicus 5008 has a special smell that could be distinguished from other tainted samples. The change of the volatiles in untainted and tainted samples was characterized using headspace solid phase microextraction (HS-SPME) combined with gas chromatography- mass spectrometry (GC-MS). Results: Seventy-one volatile compounds (including alkanes, amines, alcohols, esters, aldehydes and others) were identified and there were significant differences in the composition of volatiles among different samples. Principal component analysis (PCA) based on the GC-MS data was used to identify the important volatile compounds that contributed to the differentiation of the fermentation samples under different fermentation stages, as well as among different pollution species and fermentation media. Contamination could be discovered in time irrespective of the stage of fermentation and the contaminating bacteria in broth. Conclusion: It is the first report to detect contamination by volatile compounds in the antibiotic fermentation and it was proved that HS-SPME/GC-MS is an effective contamination detection method in Val-A production.

A rapid and non-destructive detection of Escherichia coli on the surface of fresh-cut potato slices and application using hyperspectral imaging

Abstract The contamination of foodborne Escherichia coli in fresh-cut products has become a major problem of public health around the world, so that early and rapid detection of contamination is crucial. This study explored the potential of hyperspectral imaging (HSI) measurement of contamination on the surface of fresh-cut potato slices in visible-near infrared (Vis-NIR, 400-1000 nm) region. Four preprocessing methods and the genetic algorithm (GA) were explored to handle spectral data and select characteristic wavelengths so as to establish linear and non-linear regression models. The performance of the back-propagation neural network (BP-NN) model based on full-spectrum was satisfactory, with an overall accuracy of 97.6 % and residual predictive deviation (RPD) of 6.7. Based on the BP-NN model, the research successfully explored the optimum treatment time (20 min) of a non-thermal and environmental-friendly method to inactivate the E. coli on the surface of fresh-cut potato slices, thus confirming the potential application of HSI for the first time. The overall results showed that HSI could provide a rapid and non-destructive approach for the detection of foodborne pathogens on the surface of fresh-cut products.

Preparation of highly sensitive monoclonal antibody against aflatoxin B_1 and its application in rapid detection of contamination in Ziziphi Spinosae Semen

A highly sensitive monoclonal antibody against aflatoxin B_1(AFB_1) was prepared and an indirect competition enzyme-linked immunosorbent assay(ic-ELISA) was established based on the antibody which was used for high-throughput and rapid screening of AFB_1 contamination in Chinese herbal medicines to ensure the safety of medication. In this study, the structure of AFB_1 was modified by improved oxime method, and the carrier protein was coupled by EDC-NHS method to obtain the complete antigen of AFB_1, which was more convenient and environmental friendly. The Balb/c female mice were immunized using increasing the immunization dose and various ways of injection, and finally the AFB_1 monoclonal antibody was prepared. The AFB_1 monoclonal antibody belongs to IgG_(2 b) immunoglobulin by identifying its immunological characteristics, and its sensitivity(IC_(50)) can reach 0.15 μg·L~(-1), and the affi-nity is 2.81×10~8 L·mol~(-1). The cross-reaction rates of AFB_2, AFG_1, and AFG_2 were 35.07%, 8.75%, and 1.15%, respectively, and there was almost no cross-reactivity with other mycotoxins. Based on the high sensitivity and specificity of the antibody, an ic-ELISA method was established and applied to the determination of AFB_1 contamination in Ziziphi Spinosae Semen. According to the matrix matching standard curve, the linear concentration range for AFB_1 was 0.05-0.58 μg·L~(-1)(R~2=0.992), the recoveries were 88.00%-119.0%, and the detection limit was 1.69 μg·kg~(-1). The AFB_1 in 33 batches of Ziziphi Spinosae Semen samples was determined by ic-ELISA, and the contamination level was 3.62-206.58 μg·kg~(-1). The linear correlation coefficient between the detection results of ic-ELISA and UHPLC-MS/MS was 0.996, and there were no false positive and false negative cases. It indicates that the established ic-ELISA is accurate and reliable, and could provide a simple and effective technique for fast screening of AFB_1 contamination in Ziziphi Spinosae Semen, and also could be considered as the reference for the detection and monitoring of AFB_1 contamination in other Chinese herbal medicines.

Surface-Enhanced Raman Spectroscopy for Trace Detection of Tetracycline and Dicyandiamide in Milk Using Transparent Substrate of Ag Nanoparticle Arrays

Tetracycline (TC) is an antibiotic utilized in dairy livestock, which can leave trace residues in milk and other dairy products. Dicyandiamide (DCD), a grassland fertilizer, but also potentially an adulterant to increase milk apparent protein content, has been found in milk products that were subsequently banned. Both these chemicals can pose human health risks via the consumption of dairy foods, and therefore rapid, simple detection methodologies are necessary. Herein, we fabricated a transparent and homogeneous substrate by fabricating silver nanoparticle (Ag NP) arrays based on the anodic aluminum oxide (AAO) template-assisted electrochemical deposition approach. The periodic nanostructure was optimized to obtain high SERS activity by varying nanopore diameters and Ag NP sputtering duration to have Ag NP nanogaps in the sub 10 nm regime so that the high sensitivity was achieved with detecting R6G analytes at the 1 × 10–10 M level. The substrate was also used to detect TC and DCD in milk at low concentration levels of 1 × 10–9 M and 1 × 10–7 M, respectively, with good linear correlation between concentration and intensity (TC R2 = 0.96; DCD R2 = 0.99). The assignments of Raman bands of tetracycline and dicyandiamide were also given by density-functional-theory (DFT) calculations. The advantage of this transparent SERS substrate is that it is especially useful for measurement of analytes at the interface between Ag NP substrate layer and the opaque liquid containing the analytes without special pretreatment of the sample. Thus, this method may provide an alternative practical and reliable platform for rapid detection of contaminants in foods.

Detection of Mycoplasma Contamination of Cell Culture by A Loop-Mediated Isothermal Amplification Method.

Objective Mycoplasmas are major contaminants of cell culture and affect in vitro biological and diagnostic tests. Mycoplasma detection is conducted using culture and molecular methods. These methods vary in terms of accuracy, reliably and sensitivity. Loop-mediated isothermal amplification (LAMP) is used to amplify target DNA in a highly specific and rapid manner. This study aimed to develop a LAMP method for rapid detection of Mycoplasma in culture samples. Materials and Methods In this descriptive laboratory study, for LAMP detection of Mycoplasma contaminations in cell culture, we used primers specifically designed for targeting the 16S rRNA conserved gene of Mycoplasma spp. For a positive control structure, 16S rRNA amplified based on PCR, was cloned in a plasmid vector and sequenced. The assay specificity was evaluated using Mycoplasma genomic DNA and a panel containing genomes of gram-positive and gram-negative organisms. Results In this study, the method developed for detection of Mycoplasma contamination of cell cultures was a rapid, sensitive and cost-effective LAMP approach. The results demonstrated that this method benefits from high specificity (100%) for amplification of Mycoplasma strains and high speed (multiplication within 60 minutes), while it does not require expensive laboratory equipment compared to those needed for polymerase chain reaction (PCR)-based detection. ConclusionOur study is the first report about application of LAMP assay based on 16S rRNA gene for detection of Mycoplasma strains; this technique could be considered a useful tool for rapid detection of contamination of cell culture.

Detection of drinking water contamination event with Mahalanobis distance method, using on-line monitoring sensors and manual measurement data

Abstract Concerns about drinking water (DW) quality contamination during water distribution raise a need for real-time monitoring and rapid contamination detection. Early warning systems (EWS) are a potential solution. The EWS consist of multiple conventional sensors that provide the real-time measurements and algorithms that allow the recognizing of contamination events from normal operating conditions. In most cases, these algorithms have been established with artificial data, while data from real and biological contamination events are limited. The goal of the study was the event detection performance of the Mahalanobis distance method in combination with on-line DW quality monitoring sensors and manual measurements of grab samples for potential DW biological contamination scenarios. In this study three contamination scenarios were simulated in a pilot-scale DW distribution system: untreated river water, groundwater and wastewater intrusion, which represent realistic contamination scenarios and imply biological contamination. Temperature, electrical conductivity (EC), total organic carbon (TOC), chlorine ion (Cl-), oxidation–reduction potential (ORP), pH sensors and turbidity measurements were used as on-line sensors and for manual measurements. Novel adenosine-triphosphate and flow cytometric measurements were used for biological water quality evaluation. The results showed contamination detection probability from 56% to 89%, where the best performance was obtained with manual measurements. The probability of false alarm was 5–6% both for on-line and manual measurements. The Mahalanobis distance method with DW quality sensors has a good potential to be applied in EWS. However, the sustainability of the on-line measurement system and/or the detection algorithm should be improved.

Multifunctional Nanotechnology-Enabled Sensors for Rapid Capture and Detection of Pathogens.

Nanomaterial-based sensing approaches that incorporate different types of nanoparticles (NPs) and nanostructures in conjunction with natural or synthetic receptors as molecular recognition elements provide opportunities for the design of sensitive and selective assays for rapid detection of contaminants. This review summarizes recent advancements over the past ten years in the development of nanotechnology-enabled sensors and systems for capture and detection of pathogens. The most common types of nanostructures and NPs, their modification with receptor molecules and integration to produce viable sensing systems with biorecognition, amplification and signal readout are discussed. Examples of all-in-one systems that combine multifunctional properties for capture, separation, inactivation and detection are also provided. Current trends in the development of low-cost instrumentation for rapid assessment of food contamination are discussed as well as challenges for practical implementation and directions for future research.

Authenticity analyses of Phyllanthus amarus using barcoding coupled with HRM analysis to control its quality for medicinal plant product

The Phyllanthus genus, a plant used in traditional Thai medicine, has according to several pharmacopeias hepatoprotective properties. Not only is the anatomical morphology of these species relatively similar but they also share the Thai common names Look-Tai-Bai (ลูกใต้ใบ) and Yah-Tai-Bai (หญ้าใต้ใบ), which might cause confusion for laypersons. This study attempted to develop a method for accurate identification of Phyllanthus species, especially Phyllanthus amarus, and to detect contaminants in P. amarus products by using DNA barcoding coupled with high resolution melting (HRM) analysis (bar-HRM). Two plastid loci (rbcL and trnL) were chosen for DNA barcoding to generate a suitable primer for distinguishing Phyllanthus species by HRM analysis. The five species of Phyllanthus were subjected to amplification for testing the specificity and discrimination power of the designed primers derived from rbcL and trnL regions. Sensitivity of the method (DNA barcoding conjugated with HRM) to detect adulterant in P. amarus samples was evaluated. The commercial P. amarus products obtained from a local market were authenticated. The primer pair derived from trnL DNA barcoding (PhylltrnL) had more specificity and power of discrimination for Phyllanthus species than that derived from rbcL DNA barcoding (PhyllrbcL). The result showed that Tm of P. amarus, Phyllanthus urinaria, Phyllanthus debilis, Phyllanthus airy-shawii, and Phyllanthus virgatus was 74.3±0.08, 73.04±0.07, 73.36±0.05, 72.21±0.06, 72.77±0.15°C, respectively. This method proved to be a very sensitive tool that can be used for rapid detection of contamination as low as 1% of other Phyllanthus species in P. amarus admixtures. All commercial products of P. amarus obtained from a local market in Thailand were found to contain pure raw materials of P. amarus without any substitution or contamination. Our results indicated that the use of DNA barcoding coupled with HRM was an efficient molecular tool for correct species identification. This molecular tool provides a noteworthy benefit for quality control of medicinal plants and industry plants for pharmacological prospects.

The rapid detection of E. coli 0157 Antigen in meat products by using ELISA Test Kit

This study was conducted for rapid detection of contamination of meat products with E. coli 0157 by usage of ELISA test kit as one of the most rapid and newest test. The study showed the efficiency of ELISA test kit used in this study in detection of bacteria antigen in meat products samples of raw beef meat , kabab and beef burger which subjected to improper storage conditions or undercooked and hence when some peoples uptake some of these products they suffered from clinical intoxication signs like diarrhea ,vomiting and hyperthermia. The kit showed the presence of (9) samples positive among (90) samples ; (2) positive out of (30) kabab samples,(3) positive out of (30) beef burger and (4) positive out of (30) raw beef meat after 16 hrs of enrichment of all samples in EC Modified broth including Novobiocin supplement as inhibitor of other bacteria and then the liquid supernatants from all prepared samples got tested by ELISA kit used in this study and the data recovered in less than 1 hr.The study indicated the ability of using ELISA kit for detection of E. coli 0157 antigens in food stuffs and reduce the time for releasing the results in less than 24 hrs when compared with conventional culturing procedure which reuiqred more than 3 days and launch the food products for consumption with focusing on the main point here which is the protection of our consumer safety.

Optimizing alert occurrence in the Cincinnati contamination warning system

A system designed for rapid detection of contamination in drinking water distribution systems is a novel concept, and there are no benchmarks against which to evaluate the performance of a contamination warning system (CWS). In Cincinnati, Ohio, during evaluation of the first full‐scale CWS, a primary design objective was to minimize invalid alerts without compromising the system's ability to detect true deviations from acceptable water quality conditions. This objective was important to user acceptance of the system because excessive invalid alerts can undermine user confidence and burden staff members with inconsequential investigations. During the final six months of the two‐year evaluation period, a steady‐state rate of approximately one alert per day requiring investigation was achieved. This alert rate was acceptable to the utility, and nearly all alerts were investigated by appropriate personnel. The primary conclusion drawn from the data presented is that a CWS can be optimized to achieve a reasonable and manageable rate of invalid alerts. Furthermore, the investigation of these invalid alerts required only a modest level of effort (approximately seven hours of staff time per month).

Rapid Detection of E. coli on Goat Meat by Electronic Nose

Much attention has been paid on the foodborne illness of food, which is easily contaminated with bacteria or pathogens. Escherichia coli (E.coli) is one of these bacteria that commonly live in the contaminated animal meat. There is a growing need in the food industry for pathogen detection systems that are sensitive to low levels of bacteria, specific to the target organisms, capable of yielding results at or near real time. Both contaminated and non-contaminated goat meat were tested using an electronic nose (Cyranose-320) which consists of 32 polymer sensors. We developed an electronic nose method for the rapid detection of E. coli O157:H7 in goat meat. Principal Component Analysis (PCA) method was applied to analyze the experimental data, and the results indicated that they either overlap or are very close making it very difficult for the device to correctly identify. E-nose has a potential for being used as a tool for rapid detection of contamination, although it is not able to detect very low concentration of the contaminant. Keywords: Goat meat; bacteria (E.coli); electronic nose; quality detection

RAPID DETECTION AND ENUMERATION OF CONTAMINANTS BY ATP BIOLUMINESCENCE USING THE MILLIFLEX® RAPID MICROBIOLOGY DETECTION AND ENUMERATION SYSTEM

ABSTRACT The Milliflex® Rapid Microbiology Detection and Enumeration System (RMDS) is an automated platform developed for the rapid detection of microbial contaminants in filterable samples. Based on membrane filtration, adenosine triphosphate bioluminescence and image analysis, RMDS gives microorganism enumeration a detection time reduced by a factor of four compared to plate count. After sample filtration and incubation step, a universal lysis solution and bioluminescence reagent are automatically sprayed across the membrane. The membrane is then analyzed in a detection tower where light emission is captured by a charged coupled device camera. Data collected are treated, directly providing a result in colony‐forming units. RMDS sensitivity is one cell and is equivalent to traditional microbiology. Rapid detection of bacteria, mixed bacteria and yeast was performed in various industrial samples. RMDS allowed rapid detection of contaminants in different simple and complex matrices such as water, tea, wine and mammalian cells. PRACTICAL APPLICATIONSThe Milliflex® Rapid Microbiology Detection and Enumeration System (RMDS) is used to detect and enumerate microorganisms in filterable samples with time to detection in hours.The easy handling of this detection platform enables its use in all kinds of industries from food and beverage industries to biotechnology or pharmaceutical industries where procedures and method validation are stricter. One application is the use of RMDS for purified water testing and rinsing water. Rapid enumeration of contaminants will improve the quality control analysis of industrial products. Rapid release of samples will result in the optimization of manufacturing and product testing, allowing high throughput and simultaneous analysis during the process.

Comparison of Detection Methods for <I>Acarus siro</I> (Acari: Acaridida: Acarididae) Contamination in Grain

Acarus siro L. 1758 (Acari: Acaridida: Acarididae) is an important pest of stored grain because it contaminates the grain by allergens and transfers pathogenous microorganisms. Rapid detection of contamination enables to intercept an early grain infestation by the pest. In this study, we compared the usability and efficiency of various detection approaches. Under laboratory conditions, grain samples of various sizes were infested by different levels of the following contaminants: eggs, adults, and feces of A. siro. The samples were analyzed by enzyme-linked immunosorbent assay (ELISA) by using anti-A. siro polyclonal antibody (immunochemical method), extracted in Berlese-Tullgren funnels, sieved, and processed by filth-flotation (conventional methods). The adults or juveniles of A. siro could be detected by all the three tested conventional methods and ELISA with detection limits in the range from 221 to 1,157 mites/kg grain. Eggs were detected by filth-flotation only; the detection limit was 1,950 eggs/kg grain. The feces of A. siro were detectable by ELISA test, only. ELISA enabled the detection of the feces with the minimal threshold level of 1.04 microg feces/g grain; it means the assay allowed to trace less than one metabolically active mite per gram of grain. The study thus demonstrated that reliable A. siro detection in grain can only be achieved by combining different detection methods. European Union and U.S. administratives dictate zero or near-zero tolerance level for mite infestation in stored products. This demand is difficult to fulfill, because every detection method is limited by its detection limit; thus, it is hard to reliably detect infestation levels lower than obtained detection limits. This methodical limitation is discussed in context with the determined detection limits of the tested methods.

Solid-Phase Microextraction of Organophosphate Pesticides in Source Waters for Drinking Water Treatment Facilities

The rapid detection of contaminants in our nation's drinking water has become a top homeland security priority in this time of increased national vigilance. Real-time monitoring of drinking water for deliberate or accidental contamination is key to national security. One method that can be employed for the rapid screening of pollutants in water is solid-phase microextraction (SPME). SPME is a rapid, sensitive, solvent-free system that can be used to screen for contaminants that have been accidentally or intentionally introduced into a water system. A method using SPME has been developed and optimized for the detection of seven organophosphate pesticides in drinking water treatment facility source waters. The method is tested in source waters for drinking water treatment facilities in Mississippi and Alabama. Water is collected from a deepwater well at Stennis Space Center (SSC), MS, the drinking water source for SSC, and from the Converse Reservoir, the main drinking water supply for Mobile, AL. Also tested are samples of water collected from the Mobile Alabama Water and Sewer System drinking water treatment plant prior to chlorination. The method limits of detection for the seven organophosphates were comparable to those described in several Environmental Protection Agency standard methods. They range from 0.25 to 0.94 microg/L.