Method For Detection Of Residues Research Articles

Development of an immunochromatographic strip for detection of acetamiprid in cucumber and apple samples

ABSTRACTAn immunochromatographic strip was developed for detection of acetamiprid (AC) and cross-reactivity with thiacloprid (TC) in cucumber and apple samples. This detection system was developed based on a sensitive and specific monoclonal antibody produced in our laboratory. Under optimized conditions, the cut-off limits of the test strip for AC were found to be 1 and 0.25 ng/mL for TC in phosphate-buffered saline. Meanwhile, with simple preparation for detection cucumber and apple samples, the cut-off limits for AC were found to be 5 and 2.5 ng/mL for TC in cucumber samples. The immunochromatographic assay also revealed AC cut-off values of 30 and 15 ng/mL in apple samples. Each test can be evaluated within 5 min. The data indicate that the method is sensitive, rapid, specific, and has the advantages of simplicity; therefore, this immunochromatographic assay is a useful screening method for detection of AC and TC residues in cucumber and apple samples.

Qualitative and Quantitative Drug residue analyses: Florfenicol in white-tailed deer (Odocoileus virginianus) and supermarket meat by liquid chromatography tandem-mass spectrometry.

A method for confirmation and detection of Florfenicol amine residues in white-tailed deer tissues was developed and validated in our laboratory. Tissue samples were extracted with ethyl acetate and cleaned up on sorbent (Chem-elut) cartridges. Liguid chromatography (LC) separation was achieved on a Zorbax Eclipse plus C18 column with gradient elution using a mobile phase composed of ammonium acetate in water and methanol at a flow rate of 300μL/min. Qualitative and quantitative analyses were carried out using liquid chromatography - heated electrospray ionization(HESI) and atmospheric pressure chemical ionization (APCI)-tandem mass spectrometry in the multiple reaction monitoring (MRM) interface. The limits of detection (LODs) for HESI and APCI probe were 1.8ng/g and 1.4ng/g respectively. Limits of quantitation (LOQs) for HESI and APCI probe were 5.8ng/g and 3.4ng/g respectively. Mean recovery values ranged from 79% to 111% for APCI and 30% to 60% for HESI. The validated method was used to determine white-tailed deer florfenicol tissue residue concentration 10-days after exposure. Florfenicol tissue residues concentration ranged from 0.4 to 0.6μg/g for liver and 0.02-0.05μg/g for muscle and a trace in blood samples. The concentration found in the tested edible tissues were lower than the maximum residual limit (MRL) values established by the federal drug administration (FDA) for bovine tissues. In summary, the resulting optimization procedures using the sensitivity of HESI and APCI probes in the determination of florfenicol in white-tailed deer tissue are the most compelling conclusions in this study, to the extent that we have applied this method in the evaluation of supermarket samples drug residue levels as a proof of principle.

Determination of Penicillins in Milk by a Dual-Optrode Biosensor

ABSTRACTPenicillins are the most frequently found antibiotic residues in milk, as they are commonly used for the treatment of bacterial infections in cows. In the present study, we introduce a method for the rapid detection of penicillin residues in raw milk based on the determination of glucose concentration in milk with a dual flow-through biosensor. The molar concentration of glucose in milk is typically over 500 times lower than the concentration of lactose and is highly dependent on the rate of lactose hydrolysis, which is catalyzed by β-galactosidase. Glucose concentrations in milk change with variation in the β-galactosidase activity. β-Galactosidase is an enzyme produced in the microbiota in milk and its activity is inhibited by benzylpenicillin. Spiking milk with benzylpenicillin lowers glucose concentrations in comparison to high-quality milk after short storage intervals. The presence of penicillin in the milk of treated animals resulted in decreased glucose concentrations in comparison with high-quality milk that contained no antibiotics. The glucose concentration in milk samples was followed by the system enabling the elimination of the effects of bacterial respiration in the output with reliable results in less than 1 min.

Various extraction methods for detection of bistrifluron residues in Asian pear using high-performance liquid chromatography: application to dissipation patterns under open-field conditions.

The present study was carried out to develop an analytical method for the detection and quantification of bistrifluron, a benzoylphenylurea compound, in pear using high-performance liquid chromatography with UV detection. Samples were extracted using conventional, AOAC and EN quick, easy, cheap, effective, rugged and safe 'QuEChERS' methods. As expected, conventional and EN-QuEChERS methods gave higher recoveries than AOAC. In addition, interference around the analyte retention time was observed in the conventional method. Thus, the EN-QuEChERS method was selected and validated by studying various parameters, including linearity, limit of detection, limit of quantification (LOQ), recovery and precision. Linearity was excellent, with a correlation coefficient of 0.9998. Recovery rates at three spiking levels (0.05, 0.2 and 1 mg/kg) ranged from 73.76 to 98.66%. Intra- and inter-day precisions, expressed as relative standard deviations, were <6%. The LOQ of 0.05 mg/kg was considerably lower than the maximum residue limit (1 mg/kg) set by the Korean Ministry of Food and Drug Safety. The developed method was successfully applied to open-field pear samples, in which the target analyte was slowly dissipated (55% decline) over 14 days with a half-life of 10.19 days. Notably, the residue levels throughout the period of sample collection (14 days) were lower than the maximum residue limit, indicating that the residue was not hazardous for consumers. Copyright © 2016 John Wiley & Sons, Ltd.

A novel and sensitive fluorescence immunoassay for the detection of fluoroquinolones in animal-derived foods using upconversion nanoparticles as labels

A novel fluorescence immunoassay to detect fluoroquinolones in animal-derived foods was developed for the first time by use of upconversion nanoparticles as signal-probe labels. The bioassay system was established by the use of coating-antigen-modified polystyrene particles as immune-sensing probes for separation and anti-norfloxacin monoclonal antibody conjugated with carboxyl-functionalized NaYF4:Yb,Er upconversion nanoparticles which were prepared via a pyrolysis method and a subsequent ligand exchange process as fluorescent-signal probes (emission intensity recorded at 542 nm with excitation at 980 nm). Under optimized conditions, detection of fluoroquinolones was performed easily. The detection limit of this fluorescence immunoassay for norfloxacin, for example, was 10 pg mL(-1), within a wide linear range of 10 pg mL(-1) to 10 ng mL(-1) (R (2) = 0.9959). For specificity analysis, the data obtained indicate this method could be applied in broad-spectrum detection of fluoroquinolones. The recoveries of norfloxacin-spiked animal-derived foods ranged from 82.37 to 132.22 %, with coefficients of variation of 0.24-25.06 %. The extraction procedure was rapid and simple, especially for milk samples, which could be analyzed directly without any pretreatment. In addition, the results obtained with the method were in good agreement with those obtained with commercial ELISA kits. The fluorescence immunoassay was more sensitive, especially with regard to the detection limit in milk samples (0.01 ng mL(-1) for norfloxacin): it was 50-fold more sensitive than commercial ELISA kits (0.5 ng mL(-1) for norfloxacin). The results show the proposed fluorescence immunoassay was facile, sensitive, and interference free, and is an alternative method for the quantitative detection of fluoroquinolone residues in animal-derived foods.

A fast mutant fault detection method of underwater integrated navigation

The concepts of the mean of residual and the sum of absolute residuals are introduced in this paper. Both of them along with the fault detection function are used to detect mutant fault of the assisted navigation devices in underwater integrated navigation system. (1) The traditional residual χ2 detection method is improved according to the structural characteristics of the underwater navigation system. (2) The mean of residual and the sum of absolute residuals are introduced as the characteristics of mutant faults. (3) The improved residual χ2 detection method is used to make sure of the happening of the mutant fault firstly. Then the residual mean and the sum of residual absolute values are used to distinguish the noise mutant system fault and the information mutant system fault. The results of simulations and the vehicle tests show that: (1) the mutant fault of the sub-system can be detected and the faulty sub-system can be isolated immediately when the fault appears with our novel method; (2) The noise mutant fault and the information mutant fault can be distinguished efficiently according to characteristics of the mean of residuals and the sum of the absolute residuals.

A Fast Gradual Fault Detection Method for Underwater Integrated Navigation Systems

Gradual fault detection is always an important issue in integrated navigation systems, and the gradual fault is the most difficult fault to detect. To detect gradual faults in a timely and precise manner in integrated navigation systems, the statistical concepts of the normalised residual mean and the sum of absolute residuals are introduced according to the characteristics of gradual system failure in this paper. The applicability of the improved residual χ2 detection method is discussed. Then, the gradual fault detection program based on the improved residual χ2 detection method is designed with the criterion of normalised residual mean and the sum of absolute residual. The simulation results and vehicle tests show that: 1) The residual of the failed sub-system can be calculated accurately with the improved residual χ2 detection method, which has strong applicability in gradual fault detection; 2) The gradual fault can be detected in a short time by using the normalised residual mean and the sum of absolute residual.

Two-Dimensional UV Absorption Correlation Spectroscopy as a Method for the Detection of Thiamethoxam Residue in Tea

Two-dimensional correlation spectroscopy (2D-COS) combined with UV absorption spectroscopy was evaluated as a technique for the identification of spectral regions associated with the residues of thiamethoxam in tea. There is only one absorption peak at 275 nm in the absorption spectrum of a mixture of thiamethoxam and tea, which is the absorption peak of tea. Based on 2D-COS, the absorption peak of thiamethoxam at 250 nm is extracted from the UV spectra of the mixture. To determine the residue of thiamethoxam in tea, 250 nm is selected as the measured wavelength, at which the fitting result is as follows: the residual sum of squares is 0.01375, standard deviation R2 is 0.99068, and F value is 426. Statistical analysis shows that there is a significant linear relationship between the concentration of thiamethoxam in tea and the absorbance at 250 nm in the UV spectra of the mixture. Moreover, the average prediction error is 0.0033 and the prediction variance is 0.1654, indicating good predictive result. Thus, the UV absorption spectrum can be used as a measurement method for rapid detection of thiamethoxam residues in tea.

Development of a colloidal gold-based strip test for the detection of chlorothalonil residues in cucumber

An immunochromatographic lateral flow strip test using the competitive format was developed for the determination of chlorothalonil (CTN) residues in cucumber. The limit of detection was less than 100 ng/mL by visual assessment and was found to be 91.78 ± 0.17 ng/mL for quantitative detection using a test strip reader. The recoveries of test samples were from 89.26% to 102.02% and the coefficient of variation (%) was less than 4.75%. Parallel analysis of cucumber samples with CTN showed comparable results from the strip test and high performance liquid chromatography. The strip test requires 5–8 min to complete and provides a very useful screening method for the quantitative and qualitative detection of CTN residues in cucumber.

Detection of pesticide residues on fruit surfaces using laser induced breakdown spectroscopy

The detection of chlorpyrifos residue on the surface of apples by laser induced breakdown spectroscopy (LIBS) was explored, establishing a new method for the fast detection of pesticide residues on fruit.

Methodology Studies on Detection of Aminoglycoside Residues

Aminoglycosides are a class of antibiotics commonly used in animal husbandry. If the antibiotics cannot be used legitimately, they would remain in animal foods and environment, even causing damage to human health. The effective detection to these residues is an important part of the protection of human health. In this review, the methodology studies about the detection of aminoglycoside residues are summarized for the related researchers to conveniently understand the progress of this field. These methodology studies involve multi-residue and single residue detection methods. The former includes high-performance liquid chromatography, liquid chromatography–mass spectrometry, and capillary electrophoresis, which are about 40 % of the literature we can access to. Developing the new fluorescent probe is a possible direction for these studies. The latter is about 50 % of the amount of literature, in which most are various immunoassays. The development of highly selective antibodies or aptamers is a possible direction for these assays. Since aminoglycosides have no useful absorption, their derivatization becomes an important part of the sample pretreatment. The presentations related to derivatization are about 30 % of the listed literature, and most of the rest are the purification of the samples. The development of solid-phase extraction adsorbent material which is high selectivity to this class of antibiotics and can be used repeatedly is a possible development direction.

Rapid Double-Layer Identification Method of Multi-Relevant Bad Data in Large-Scale Power Grids

Bad data detection and identification is an important part of state estimation. When the relevant bad data appears, however, there is residual pollution and residual submerged condition in currently available methods of bad data detection and identification. In view of the above problem, this article presents a double-layer bad data detection and identification technique. At first, it is based on regularization residual detection method (Rn detection method) to identify the suspect measurement sets. And then, it presents a fast search technique of interrelated suspect measurements to search interrelated measurements in all the suspect measurements of the entire power grid and produce interrelated suspect measurement sets. Furthermore, use double-layer identification method to fast identify the bad data in interrelated suspect measurement sets, in other words, identify all the bad data in entire power grid. At last, taking IEEE39 node power grid for example, this detection method of bad data is analyzed, the accuracy and effectiveness of this method is to be verified.

Improving Diagnostic Methods for Minimal Residual Disease Detection (MRD) in Childhood Acute Lymphoblastic Leukemia (ALL)

Improving Diagnostic Methods for Minimal Residual Disease Detection (MRD) in Childhood Acute Lymphoblastic Leukemia (ALL)

Monitoring the presence of 13 active compounds in surface water collected from rural areas in northwestern Spain.

Drug residues are considered environmental contaminants, and their occurrence has recently become a matter of concern. Analytical methods and monitoring systems are therefore required to control the continuous input of these drug residues into the environment. This article presents a suitable HPLC-ESI-MS/MS method for the simultaneous extraction, detection and quantification of residues of 13 drugs (antimicrobials, glucocorticosteroids, anti-inflammatories, anti-hypertensives, anti-cancer drugs and triphenylmethane dyes) in surface water. A monitoring study with 549 water samples was carried out in northwestern Spain to detect the presence of drug residues over two sampling periods during 2010, 2011 and 2012. Samples were collected from rural areas with and without farming activity and from urban areas. The 13 analytes were detected, and 18% of the samples collected showed positive results for the presence of at least one analyte. More collection sites were located in rural areas than in urban areas. However, more positive samples with higher concentrations and a larger number of analytes were detected in samples collected from sites located after the discharge of a WWTP. Results indicated that the WWTPs seems to act as a concentration point. Positive samples were also detected at a site located near a drinking water treatment plant.

Surface-Enhanced Raman Spectroscopic Analysis of Phorate and Fenthion Pesticide in Apple Skin Using Silver Nanoparticles

Traditional pesticide residue detection methods are usually complicated, time consuming, and expensive. Rapid, portable, online, and real-time detection kits are the developing direction of pesticide testing. In this paper, we used a surface-enhanced Raman spectroscopy (SERS) technique to detect the organophosphate pesticide residue of phorate and fenthion in apple skin, for the purpose of finding a fast, simple, and convenient detection method for pesticide detection. The results showed that the characteristic wavenumbers of the two organophosphorus pesticides are more easily identified using SERS. We selected the Raman peaks at 728 cm(-1) of phorate and 1215 cm(-1) of fenthion as the target peaks for quantitative analysis, and utilized internal standards to establish linear regression models for phorate and fenthion. The detection limit was 0.05 mg/L for phorate and 0.4 mg/L for fenthion. This method can be used as a quantitative analytical reference for the detection of phorate and fenthion.

Determination of Pesticides Residues in Brazilian Grape Juices Using GC-MS-SIM

The production of grape juice in Brazil is growing at a 30 % rate a year. To increase exports, a full complainment to food safety protocols, as those in the Codex Alimentarius, is mandatory. Simple and fast analytical methods are needed for quality assurance. The objective of this work was to develop and validate an analytical method for detection of pesticides residues (organochlorides, organophosphorides, and fungicides) in Brazilian whole grape juices. The analyses were performed by gas chromatography coupled to mass spectrometry, operating in selective ion monitoring. After liquid–liquid extraction, samples were preconcentrate using solid-phase extraction in Florisil. The limit of quantification ranged from 3.75 to 9.47 mg l-1, and recovery varied from 84.0 % to 99.7 %, with RSD lower than 4.9 %. From a total of 99 Brazilian grape juices analyzed, pesticide residues were found in 32.

Rapid, in situ detection of cocaine residues based on paper spray ionization coupled with ion mobility spectrometry

In this paper, a novel approach based on paper spray ionization coupled with ion mobility spectrometry (PSI-IMS) was developed for rapid, in situ detection of cocaine residues in liquid samples and on various surfaces (e.g. glass, marble, skin, wood, fingernails), without tedious sample pretreatment. The obvious advantages of PSI are its low cost, easy operation and simple configuration without using nebulizing gas or discharge gas. Compared with mass spectrometry, ion mobility spectrometry (IMS) takes advantage of its low cost, easy operation, and simple configuration without requiring a vacuum system. Therefore, IMS is a more congruous detection method for PSI in the case of rapid, in situ analysis. For the analysis of cocaine residues in liquid samples, dynamic responses from 5 μg mL(-1) to 200 μg mL(-1) with a linear coefficient (R(2)) of 0.992 were obtained. In this case, the limit of detection (LOD) was calculated to be 2 μg mL(-1) as signal to noise (S/N) was 3 with a relative standard deviation (RSD) of 6.5% for 11 measurements (n = 11). Cocaine residues on various surfaces such as metal, glass, marble, wood, skin, and fingernails were also directly analyzed before wiping the surfaces with a piece of paper. The LOD was calculated to be as low as 5 ng (S/N = 3, RSD = 6.3%, n = 11). This demonstrates the capability of the PSI-IMS method for direct detection of cocaine residues at scenes of cocaine administration. Our results show that PSI-IMS is a simple, sensitive, rapid and economical method for in situ detection of this illicit drug, which could help governments to combat drug abuse.

Design of Detection System for Residual Voltage Based on SOPC

In accordance with the relevant safety standard requirements for electrical equipment, this thesis proposes a residual voltage detection method with high accuracy and low power consumption . The power frequency synchronization signal is obtained by the measuring instrument with the zero-crossing detection circuit used. In the power frequency AC peak moment the measured instrument's power is cut off and the measured equipment's residual voltage is sampled by the input circuit with the high input impedance. Under the control of the NIOSII, the on-line detection of power-down residual voltage of equipment after the 1second and 10seconds is realized with the high speed sampling /hold-circuit and high precision ADC module used. The experimental result shows that the measuring instrument has good stability, with measurement accuracy up to 0.506%, meeting the measurement requirements.

Validation Study of the BetaStar® Plus Lateral Flow Assay for Detection of Beta-Lactam Antibiotics in Milk

A validation study designed to meet the requirements of the AOAC Research Institute and the U.S. Food and Drug Administration, Center for Veterinary Medicine (FDA/CVM) was conducted for a receptor and antibody-based, immunochromatographic method (BetaStar Plus) for detection of beta-lactam antibiotic residues in raw, commingled bovine milk. The assay was found to detect amoxicillin, ampicillin, ceftiofur, cephapirin, cloxacillin, and penicillin G at levels below the FDA tolerance/safe levels, but above the maximum sensitivity thresholds established by the National Conference on Interstate Milk Shipments (NCIMS). Results of the part I (internal) and part II (independent laboratory) dose-response studies employing spiked samples were in close agreement. The test was able to detect all six drugs at the approximate 90/95% sensitivity levels when presented as incurred residues in milk collected from cows that had been treated with the specific drug. Selectivity of the assay was 100%, as no false-positive results were obtained in testing of 1031 control milk samples. Results of ruggedness experiments established the operating parameter tolerances for the BetaStar Plus assay. Results of cross-reactivity testing established that the assay detects certain other beta-lactam drugs (dicloxacillin and ticarcillin), but it does not cross-react with any of 30 drugs belonging to other classes. Abnormally high bacterial or somatic cell counts in raw milk produced no interference with the ability of the test to detect beta-lactams at tolerance/safe levels.

Thin-Film Residual Stress Detection Method Based on Flexible Hinges

The residual stress introduced in the thin-film process may caused some problems, especially after removing of the sacrificial layers below, the suspended structure may be bended due to the release. In this articles we will develop a new in-situ residual stress detection method based on flexible hinges for thin-film materials, then described the detection principle theoretically and simulated its properties by FEA method.