scholarly journals Automated Photochemically Induced Method for the Quantitation of the Neonicotinoid Thiacloprid in Lettuce

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4089 ◽  
Author(s):  
J. Jiménez-López ◽  
E.J. Llorent-Martínez ◽  
S. Martínez-Soliño ◽  
A. Ruiz-Medina
Keyword(s):  
Uv Light ◽  
Flow Cell ◽  
Solid Support ◽  
The European Union ◽  
Maximum Residue Limit ◽  
Method Detection Limit ◽  
Real Samples ◽  
Sample Throughput ◽  
All Solutions ◽  
Relative Standard

In this work, we present an automated luminescence sensor for the quantitation of the insecticide thiacloprid, one of the main neonicotinoids, in lettuce samples. A simple and automated manifold was constructed, using multicommutated solenoid valves to handle all solutions. The analyte was online irradiated with UV light to produce a highly fluorescent photoproduct (λexc/λem = 305/370 nm/nm) that was then retained on a solid support placed in the flow cell. In this way, the pre-concentration of the photoproduct was achieved in the detection area, increasing the sensitivity of the analytical method. A method-detection limit of 0.24 mg kg−1 was achieved in real samples, fulfilling the Maximum Residue Limit (MRL) of The European Union for thiacloprid in lettuce (1 mg kg−1). A sample throughput of eight samples per hour was obtained. Recovery experiments were carried out at values close to the MRL, obtaining recovery yields close to 100% and relative standard deviations lower than 5%. Hence, this method would be suitable for routine analyses in quality control, as an alternative to other existing methods.

scholarly journals SIMULTANEOUS DETERMINATION OF DIPHENHYDRAMINE, EPHEDRINE, NOSCAPINE, AND GLYCEROL GLYCOLATE USING STABILITY-INDICATING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY: APPLICATION TO NOSCOF TABLETS

2019 ◽  
pp. 505-511
Author(s):  
PULAGURTHA BHASKARARAO ◽  
GOWRI SANKAR DANNANA
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Uv Light ◽  
Reversed Phase ◽  
Hplc Method ◽  
Stability Indicating ◽  
Rp Hplc ◽  
Relative Standard ◽  
Validation Parameters

Objective: Noscof tablet is a fixed dosage combination formulation having diphenhydramine (DH), ephedrine (ED), noscapine (NP), and glycerol glycolate (GG). A sensitive, selective, accurate, precise, and stability-indicating reversed-phase high-performance liquid chromatography (RP-HPLC) method with photodiode array detection has been developed and validated for simultaneous analysis of DH, ED, NP, and GG in bulk drug and Noscof tablets. Methods: Reversed-phase chromatographic separation and analysis of DH, ED, NP, and GG were done on an Altima C18 column with 0.01 M KH2PO4 buffer (pH 3.5) and acetonitrile (50:50%, v/v) as mobile phase at 0.8 ml/min flow rate in isocratic mode. Detection was performed at 260 nm. The method was validated in harmony with International Conference on Harmonization (ICH) guidelines. The tablet sample solution was subjected to diverse stress conditions using ICH strategy such as hydrolytic degradation (neutral - with distilled water, alkaline - with 2 N NaOH, and acidic - with 2 N HCl), oxidation (with 10% H2O2), photodegradation (exposing to UV light), and dry heat degradation (exposing to 105°C). Results: Using the above stated chromatographic conditions, sharp peaks were obtained for ED, NP, DH, and GG with retention time of 3.272 min, 4.098 min, 5.467 min, and 6.783 min, respectively. Good regression coefficient values were obtained in the range of 2–12 μg/ml for ED, 3.75–22.5 μg/ml for NP, 3.125–18.75 μg/ml for DH, and 25–150 μg/ml for GG. The quantification limits were 0.181 μg/ml, 0.187 μg/ml, 0.246 μg/ml, and 1.114 μg/ml for ED, NP, DH, and GG, respectively. The values of validation parameters are within the acceptance limits given by ICH. The ED, NP, DH, and GG showed more percent of degradation in acid condition and less percent of degradation in the neutral condition. The peaks of degradants did not interfere with the peaks of analytes. ED, NP, DH, and GG were assessed with a good percentage of the assay (near to 100%) and low percent relative standard deviation (<2%) in Noscof tablets using the proposed method. Conclusion: The stability indicating RP-HPLC method developed was suitable for quantifying ED, NP, DH, and GG simultaneously in bulk as well as in tablet formulation.

scholarly journals Determination of Pesticide Residues in Honey by Single-Drop Microextraction and Gas Chromatography

2011 ◽  
Vol 94 (2) ◽  
pp. 634-644 ◽  
Author(s):  
Nikolaos G Tsiropoulos ◽  
Elpiniki G Amvrazi
Keyword(s):  
Pesticide Residues ◽  
Enrichment Factors ◽  
The European Union ◽  
Maximum Residue Limit ◽  
Single Drop ◽  
Limit Values ◽  
Screening Design ◽  
Single Drop Microextraction ◽  
Central Composite

Abstract A novel, simple, and rapid single-drop microextraction (SDME) procedure combined with GC has been developed, validated, and applied for the determination of multiclass pesticide residues in honey samples. The SDME was optimized using a Plackett-Burman screening design considering all parameters that may influence an SDME procedure and a consequent central composite design to control the parameters that were found to significantly influence the pesticide determination. The developed analytical method required minimal volumes of organic solvents and exhibited good analytical characteristics with enrichment factors ranging from 3 for -endosulfan to 10 for lindane, procymidone, and captan and method quantification limits ranging from 0.03 g/kg for phosalone to 10.6 g/kg for diazinon. The relative recoveries obtained ranged from 70.8 for captan to 120 for fenarimol, and the precision (RSD) ranged from 3 to 15. The proposed SDME procedure followed by GC with an electron capture detector for quantification and GC/MS for identification was applied with success to the analysis of 17 honey samples. Monitoring results indicated a low level of honey contamination by diazinon, chlorpyrifosethyl, procymidone, bromopropylate, and endosulfan (-, -, and endosulfan sulfate) residues that were far below the maximum residue limit values specified by the European Union for endosulfan (10 g/kg) and bromopropylate (100 g/kg) in honey samples.

Flow-injection analysis with chemiluminescence detection.

1979 ◽  
Vol 25 (9) ◽  
pp. 1635-1638 ◽  
Author(s):  
G Rule ◽  
W R Seitz
Keyword(s):  
Flow Injection ◽  
Flow Injection Analysis ◽  
Detection System ◽  
Sample Volume ◽  
Chemiluminescence Detection ◽  
Cupric Ion ◽  
Peak Overlap ◽  
Sample Throughput ◽  
Relative Standard ◽  
Replicate Measurements

Abstract In "flow-injection analysis," the sample is inserted into a stream of reagent by use of a sample-injection valve. Mixing occurs downstream from the valve in a coil of tubing. With chemiluminescence detection this coil is positioned in front of a photomultiplier. We have evaluated the system for detection of hydrogen peroxide, using the luminol reaction with cupric ion as a catalyst. The effects of flow rate, sample volume, and reaction kinetics on the magnitude, duration, and repeatability of the chemiluminescent response have been evaluated. Precisions of 1 to 2% relative standard deviation on replicate measurements are readily achievable. A sample throughput of six samples per minute is possible with very little peak overlap. This detection system can be coupled to any process in which peroxide is generated.

Detection Limits of β-Lactam Antibiotics in Ewe Milk by Penzym Enzymatic Test

2001 ◽  
Vol 64 (11) ◽  
pp. 1844-1847 ◽  
Author(s):  
R. L. ALTHAUS ◽  
M. P. MOLINA ◽  
M. RODRIGUEZ ◽  
N. FERNANDEZ
Keyword(s):  
Detection Limits ◽  
Penicillin G ◽  
Specific Method ◽  
The European Union ◽  
Maximum Residue Limit ◽  
Logistic Regression Models ◽  
Lactam Antibiotic ◽  
Short Time ◽  
Positive Results ◽  
Enzymatic Test

The Penzym is an enzymatic test widely used for the detection of β-lactam antibiotic residuals in milk. It is a specific method with good sensitivity to this group of antibiotics and enables results to be obtained within a short time. In the present work, the detection limits of 10 β-lactam antibiotics were determined in ewe milk, given the lack of previous studies of the Penzym test in ovine milk. For each antibiotic, eight concentrations were tested on 20 ewe milk samples proceeding from individual ewes (160 analyses per drug). The limits of the Penzym test were determined by means of logistic regression models, as follows: 5 μg/kg amoxicillin, 4 μg/kg ampicillin, 33 μg/kg cloxacillin, 3 μg/kg penicillin “G,” 43 μg/kg ce-phadroxil, 10 μg/kg cephalosporin “C,” 16 μg/kg cephalexin, 900 μg/kg cephoperazone, 120 μg/kg Ceftiofur, and 77 μg/kg cephuroxime. The percentages of positive results for those antibiotics at the maximum residue limit (MRL) concentration established by the European Union (EU) were: 100% (penicillin “G”), 93.3% (ampicillin), 93.3% (cloxacillin), 56.7% (Ceftiofur), and 56.7% (amoxicillin).

An improved method for determining HNMs in drinking water

2013 ◽  
Vol 13 (5) ◽  
pp. 1257-1264 ◽  
Author(s):  
F. Q. Huang ◽  
M. Y. Ruan ◽  
J. D. Yan ◽  
H. C. Hong ◽  
H. J. Lin ◽  
...  
Keyword(s):  
Drinking Water ◽  
Extraction Efficiency ◽  
Tap Water ◽  
Correlation Coefficients ◽  
Method Detection Limit ◽  
Good Reliability ◽  
Liquid Liquid Extraction ◽  
Relative Standard ◽  
Water Ph

Halonitromethanes (HNMs) in drinking water are increasingly becoming a public concern due to their high health risks, so development of a sensitive method for their analysis has become a priority. Liquid–liquid extraction (LLE) method is dominantly used in current studies regarding HNMs. However the sensitivity is far from ideal. The present study aims to investigate the factors that may influence the extraction efficiency during HNM analysis by LLE method, and as a result develop a more sensitive extraction method for HNM determination. Results showed that the dose of sodium sulfate exerted the most significant influence, followed by copper sulfate, while the pH and manual shaking times have little effect. Under the suitable conditions (for extracting HNMs in 45 mL water: pH = 3.5–5, CuSO4 = 1.0 g, Na2SO4 = 6 g, shaking times = 120–180), the correlation coefficients (r) of the calibration curves for nine HNMs were all more than 0.9925. The method detection limit (MDL) ranged from 0.017 to 0.217 μg L−1 with an average of 0.076 μg L−1, which was dominantly lower than the method reported. The recovery (spiked blank samples: 98–108%; spiked tap water: 81–120%) and precision (relative standard deviation: 0.46–6.72) also showed good reliability and reproducibility of the method. Finally, the developed method was applied to the determination of HNMs in real water samples.

scholarly journals H-point Standard Addition Method for the Simultaneous Spectrophotometric Determination of Captopril and Hydrochlorothiazide in Pharmaceutical Formulations

2021 ◽  
pp. 77-85
Keyword(s):  
Spectrophotometric Determination ◽  
Standard Addition ◽  
Pharmaceutical Formulations ◽  
Standard Addition Method ◽  
Addition Method ◽  
Real Samples ◽  
Relative Standard ◽  
Recovery Percentage ◽  
Precision And Accuracy

Simultaneous spectrophotometric determination of captopril and hydro-chlorothiazide in pharmaceutical formulations by the H-point standard addition method (HPSAM) is described. Absorbance at 211.5 and 230.3 nm was monitored upon the addition of standard solutions of captopril. The results showed that in prepared mixtures, captopril and hydrochlorothiazide can be determined simultaneously at concentration ratios varying from 1.0:0.8 to 2.5:1.5 μg/mL, respectively. Percentage recovery was found to be 95.33–104.37% for captopril and 96.8–105% for hydrochlorothiazide, with a relative standard deviation (RSD) of 2.46%. The method was successfully used to evaluate the antihypertensive captopril drug in a binary combination of hydrochlorothiazide in real samples with high precision and accuracy within the recovery percentage.

scholarly journals RP-HPLC (STABILITY-INDICATING) BASED ASSAY METHOD FOR THE SIMULTANEOUS ESTIMATION OF DORAVIRINE, TENOFOVIR DISOPROXIL FUMARATE AND LAMIVUDINE

2021 ◽  
pp. 153-159
Author(s):  
V. L. N. BALAJI GUPTA TIRUVEEDHI ◽  
VENKATESWARA RAO BATTULA ◽  
KISHORE BABU BONIGE
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Uv Light ◽  
Volume Ratio ◽  
Assay Method ◽  
Simultaneous Estimation ◽  
Intermediate Precision ◽  
Stability Indicating ◽  
Rp Hplc ◽  
Relative Standard ◽  
The Stability

Objective: In this study, a RP-HPLC (stability-indicating) based assay method for the estimation of doravirine (DRV), tenofovir disoproxil fumarate (TFF) and lamivudine (LMV) simultaneously in the tablets was described. Methods: The simultaneous analysis of DRV, TFF and LMV was done with HPLC system (Agilent 1100 series) and Luna Phenomenex C18 (250 mm × 4.6 mm × 5 μ) column with isocratic mobile phase (35% volume ratio of methanol and 65% volume ratio of 20 mmol ammonium formate, pH 5). Validation of assay method was done on sensitivity, linearity, accuracy, selectivity, precision, robustness and specificity. Results: The calibration curves were linear through the range of 25-200 µg/ml for DRV and 75-600 µg/ml for TFF and LMV. The percent relative standard deviation for intraday variation/precision, interday variation/precision, intermediate precision/ruggedness and robustness were lower than 2%. The recovery of LMV (99.09-99.76%), TFF (99.10-99.41%) and DRV (98.65-99.28%) confirmed the good accuracy. The stability of LMV, TFF and DRV in 0.1N NaOH, 3% peroxide, 0.1 N HCl, UV light and dry heat of 60 °C was determined. Conclusion: The results have allowed the method to be implemented in the tablets to quantify DRV, TFF, and LMV.

scholarly journals Quantitative determination of curcumin, demethoxycurcumin and bisdemethoxycurcumin from dietary supplements using HPLC-UV

2019 ◽  
Vol 2 (3) ◽  
pp. 10-17
Author(s):  
Giang Nguyen Huong ◽  
Nhan Do Ngoc ◽  
Son Pham Van ◽  
Duy Nguyen Bui ◽  
Lu Ngo Thi ◽  
...  
Keyword(s):  
Dietary Supplements ◽  
High Performance ◽  
Reliable Method ◽  
Ho Chi Minh City ◽  
Uv Detector ◽  
Limits Of Detection ◽  
Average Recovery ◽  
Real Samples ◽  
Relative Standard

A simple, sensitive and reliable method was developed and applied to determine curcumin, demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC) (curcuminoid) in dietary supplements by High-Performance Liquid Chromatography using UV detector (HPLC-UV). The method was validated for linearity, repeatability, reproducibility, limits of detection and limits of quantification. The limits of detection and limits of quantification of curcuminoids were found to be 10 mg/kg and 40 mg/kg, respectively. The calibration curve showed good linearity for the three compounds (R2 &gt; 0,999). The average recovery rates of curcuminoid at three spiked levels ranged from 90.3% to 106.7% and the relative standard deviations were less than 2.0%. The method has also been successfully applied to analyze curcuminoid in the real samples collected in Ho Chi Minh City.

scholarly journals Europium Fluorescent Nanoparticles-Based Multiplex Lateral Flow Immunoassay for Simultaneous Detection of Three Antibiotic Families Residue

2021 ◽  
Vol 9 ◽  
Author(s):  
Yaping Wang ◽  
Biao Ma ◽  
Miaomiao Liu ◽  
Erjing Chen ◽  
Ying Xu ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Quantitative Analysis ◽  
Uv Light ◽  
Simultaneous Detection ◽  
Rapid Screening ◽  
Quantitative Detection ◽  
Fluorescent Nanoparticles ◽  
Antibiotic Residues ◽  
Detection Range ◽  
Relative Standard

A fluorescent immunoassay based on europium nanoparticles (EuNPs-FIA) was developed for the simultaneous detection of antibiotic residues, solving the problems of single target detection and low sensitivity of traditional immunoassay methods. In the EuNPs-FIA, EuNPs were used as indictive probes by binding to anti-tetracyclines monoclonal antibodies (anti-TCs mAb), anti-sulphonamides monoclonal antibodies (anti-SAs mAb) and anti-fluoroquinolones monoclonal antibodies (anti-FQs mAb), respectively. Different artificial antigens were assigned to different regions of the nitrocellulose membrane as capture reagents. The EuNPs-FIA allowed for the simultaneous detection of three classes of antibiotics (tetracyclines, fluoroquinolones and sulphonamides) within 15 min. It enabled both the qualitative determination with the naked eye under UV light and the quantitative detection of target antibiotics by scanning the fluorescence intensity of the detection probes on the corresponding detection lines. For qualitative analysis, the cut-off values for tetracyclines (TCs), fluoroquinolones (FQs) and sulphonamides (SAs) were 3.2 ng/ml, 2.4 ng/ml and 4.0 ng/ml, respectively, which were much lower than the maximum residue limit in food. For quantitative analysis, these ranged from 0.06 to 6.85 ng/ml for TCs, 0.03–5.14 ng/ml for FQs, and 0.04–4.40 ng/ml for SAs. The linear correlation coefficients were higher than 0.97. The mean spiked recoveries ranged from 92.1 to 106.2% with relative standard deviations less than 8.75%. Among them, the three monoclonal antibodies could recognize four types of TCs, seven types of FQs and 13 types of SAs, respectively, and the detection range could cover 24 antibiotic residues with different structural formulations. The results of the detection of antibiotic residues in real samples using this method were highly correlated with those of high performance liquid chromatography (R2 &gt; 0.98). The accuracy and precision of the EuNPs-FIA also met the requirements for quantitative analysis. These results suggested that this multiplex immunoassay method was a promising method for rapid screening of three families of antibiotic residues.

scholarly journals AVALIAÇÃO DA PRESENÇA DE PESTICIDAS N-METILCARBAMATOS E SEUS PRODUTOS DE DEGRADAÇÃO NAS ÁGUAS DA REGIÃO DE PARÁ DE MINAS (MG) BRASIL

2001 ◽  
Vol 11 ◽  
Author(s):  
FABRÍCIO VILELA PARREIRA ◽  
EUCLER B. PANIAGO ◽  
CIOMARA RABELO DE CARVALHO ◽  
ROBSON JOSÉ DE CÁSSIA FRANCO AFONSO
Keyword(s):  
Water Samples ◽  
High Performance ◽  
Solid Phase ◽  
Degradation Products ◽  
Phase Extraction ◽  
Method Detection Limit ◽  
Ultraviolet Detector ◽  
Brazilian Legislation ◽  
Relative Standard ◽  
The City

Os pesticidas N-metilcarbamatos e alguns de seus metabólitos são altamente tóxicos para o homem e o meio ambiente. Por esta razão desenvolveu-se método analítico utilizando extração em fase sólida e cromatografia líquida de alta eficiência com detector de ultravioleta (CLAE/UV) para análise destes compostos em amostras de água. O método apresentou índice de recuperação para 10 compostos de 57 a 99%, com desvio padrão relativo (CV) de 5,67 a 7,67% para n=6. A repetitividade do método forneceu CV entre 5,94 a 8,46% para n=6. O limite de detecção do método (MDL) situou-se na faixa de 0,07 a 0,38 µg/L para 10 compostos. Este método foi aplicado na análise de amostras de águas coletadas na cidade de Pará de Minas-MG, Brasil, e também em alguns pontos selecionados nas bacias dos Rios Paciência e Bom Sucesso, situadas no município de Pará de Minas. Os resultados das análises em amostras de água mostraram-se abaixo dos limites estabelecidos pela legislação brasileira. EVALUATION OF THE PRESENCE OF N-METHYLCARBAMATE PESTICIDES AND DEGRADATION PRODUCTS IN WATERS OF PARÁ DE MINAS (MG) REGION IN BRAZIL Abstract The N-methylcarbamate pesticides and some of the their metabolites are highly toxic for men and environment. Then, an analytical method utilizing solid phase extraction and high performance liquid chromatography with ultraviolet detector (SPE/CLAE/UV) to analyze these compounds in water was developed. The accuracy of the method for 10 compounds varied from 57 to 99%, presenting relative standard deviation (RSD) from 5,67 to 7,67% for n=6. The repeatability supplied RSD among 5,94 to 8,46% for n=6. The method detection limit (MDL) is in the ranging of 0,07 to 0,38 µg/L for 10 compounds. This method was utilized in water samples collected in the city of Pará de Minas (MG) and in several points of the rivers Paciência e Bom Sucesso, situated in Pará de Minas (MG), Brazil. The results of the analysis of water samples are bellow of the limits permitted by Brazilian legislation.

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