scholarly journals A Fully Automated System for Analysis of Pesticides in Water: On-Line Extraction Followed by Liquid Chromatography- Tandem Photodiode Array/Postcolumn Derivatization/ Fluorescence Detection

1999 ◽  
Vol 82 (4) ◽  
pp. 968-981 ◽  
Author(s):  
John Patsias ◽  
Euphemia Papadopoulou-Mourkidou
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Automated System ◽  
Array Detector ◽  
Fluorescence Detector ◽  
Relative Standard ◽  
On Line ◽  
Photodiode Array ◽  
Postcolumn Derivatization ◽  
Fully Automated System

Abstract A fully automated system for on-line solid phase extraction (SPE) followed by high-performance liquid chromatography (HPLC) with tandem detection with a photodiode array detector and a fluorescence detector (after postcolumn derivatization) was developed for analysis of many chemical classes of pesticides and their major conversion products in aquatic systems. An automated on-line-SPE system (Prospekt) operated with reversed-phase cartridges (PRP-1) extracts analytes from 100 mL acidified (pH = 3) filtered water sample. On-line HPLC analysis is performed with a 15 cm C18 analytical column eluted with a mobile phase of phosphate (pH = 3)-acetonitrile in 25 min linear gradient mode. Solutes are detected by tandem diode array/ derivatization/fluorescence detection. The system is controlled and monitored by a single computer operated with Millenium software. Recoveries of most analytes in samples fortified at 1 μg/L are >90%, with relative standard deviation values of <5%. For a few very polar analytes, mostly Λ/-methylcarbamoyloximes (i.e., aldicarb sulfone, methomyl, and oxamyl), recoveries are <20%. However, for these compounds, as well as for the rest of the N-methylcarbamates except for aldicarb sulfoxide and butoxycarboxim, the limits of detection (LODs) are 0.005-0.05 μg/L. LODs for aldicarb sulfoxide and butoxycarboxim are 0.2 and 0.1 μg, respectively. LODs for the rest of the analytes except 4-nitrophenol, bentazone, captan, decamethrin, and MCPA are 0.05-0.1 μg/L. LODs for the latter compounds are 0.2-1.0 μg/L. The system can be operated unattended.

scholarly journals Simultaneous Quantification of Two Flavonoids in Morus alba by High Performance Liquid Chromatography Coupled with Photodiode Array Detector

2018 ◽  
Vol 13 (11) ◽  
pp. 1934578X1801301
Author(s):  
Chang-Seob Seo ◽  
Hyeun-Kyoo Shin
Keyword(s):  
Quality Control ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Morus Alba ◽  
Array Detector ◽  
Root Bark ◽  
Relative Standard ◽  
Photodiode Array

The root bark of Morus alba L. (Family: Moraceae) is an important medicinal herb in many countries and has long been used as a traditional medicine for the treatment of cough, fever, blood pressure reduction, and respiratory diseases. In the present study, the simultaneous determination of two flavonoids, kuwanon G and morusin, for quality control of M alba was conducted using high-performance liquid chromatography (HPLC) equipped with photodiode array (PDA) detector. The column used for separation of kuwanon G and morusin was a Gemini C18 analytical column maintained at 45°C. The mobile phase for efficient separation of two analytes was flowed 0.1% (v/v) aqueous formic acid-acetonitrile with gradient elution. The detection wavelength for quantification was set at 266 nm. The optimized method showed good linearity with coefficients of determination of 0.9998 within the tested concentration ranges. The limits of detection for the two flavonoids, kuwanon G and morusin, were 0.69 μg/mL and 0.35 μg/mL and the limits of quantification of kuwanon G and morusin, were 2.10 μ/mL and 1.07 μg/mL. The recoveries were 98.40–111.55% and the relative standard deviation (RSD) value was within 3.50%. The RSD values of intra- a g d interday precisions were 0.08–0.70% and 0.06-0.48%, respectively. The amounts of kuwanon G and morusin were 1.94-2.26 mg/g and 1.05–1.12 mg/g. The established HPLC-PDA method will help to improve the quality control of M. alba and related products.

scholarly journals Determination of Sulfonamide Residues in Eggs by Liquid Chromatography

2002 ◽  
Vol 85 (4) ◽  
pp. 848-852 ◽  
Author(s):  
Naoto Furusawa
Keyword(s):  
Liquid Chromatography ◽  
Mobile Phase ◽  
Array Detector ◽  
Photodiode Array Detector ◽  
Relative Standard ◽  
Photodiode Array ◽  
Standard Deviations ◽  
Sulfonamide Residues ◽  
Centrifugal Ultrafiltration

Abstract A method was developed for determining residual sulfonamide antibacterials such as sulfamethazine (SMZ), sulfamonomethoxine (SMM), sulfadimethoxine (SDM), and sulfaquinoxaline (SQ) in eggs using liquid chromatography with a photodiode array detector. The spiked and blank samples were cleaned up by using an Ultrafree®-MC/PL centrifugal ultrafiltration unit. A Mightysil® RP-4 GP column and a mobile phase of 28% (v/v) ethanol–H2O with a photodiode array detector were used for the determination. Average recoveries from eggs spiked with each drug at 0.1, 0.2, 0.4, and 1.0 ppm were ≥80.9%, with relative standard deviations between 1.3 and 4.7%. The limits of quantitation were 0.060 ppm for SMZ, 0.045 for SMM, 0.044 for SDM, and 0.093 for SQ. The analysis of one sample required <30 min and <5 mL ethanol as solvent.

Determination of the Malachite Green in Sediment by High Performance Liquid Chromatography with Fluorescence Detection

2013 ◽  
Vol 781-784 ◽  
pp. 942-946 ◽  
Author(s):  
Jian Chao Deng ◽  
Xian Qing Yang ◽  
Lai Hao Li ◽  
Jian Wei Cen ◽  
Shu Xian Hao ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Malachite Green ◽  
Fluorescence Detection ◽  
High Performance ◽  
Solid Phase ◽  
Fluorescence Detector ◽  
Sediment Samples ◽  
Relative Standard

A new method of determination of malachite green (MG) in sediment has been developed by high performance liquid chromatography with fluorescence detection (HPLC-FLD). It is based on use of a deoxidation reaction which converts malachite green (MG) into LMG in the process of extraction. The sediment samples were extracted with a solution of formic acid and acetonitrile. Clean up and isolation was performed on MCX solid phase extraction (SPE) column. Chromatographic separation was achieved by using C18column with an isocratic mobile phase consisting of acetonitrile and ammonium acetate buffer (0.05 M, pH 4.5) (80:20, v/v). High performance liquid chromatography with fluorescence detector (λex=265 nm and λem=360 nm) was used for the determination of LMG. The recovery values of MG in sediment samples fortified with MG were determined by measuring the amount of MG in the samples, after carrying out deoxidation reaction with potassium borohydride, which converts the MG into LMG. Under the optimized conditions, the average recoveries of MG from sediment at three levels (1.0, 10 and 50 μg/kg) were 85.0% (range from 80.8 to 87.6%). Relative standard deviations (RSD) of recoveries at all fortification levels were less than for 9.57% for MG. The method detection limit obtained for MG was 0.5 μg/kg.

Determination of Small Quantities of Atropine in Commercial Preparations by Liquid Chromatography with Fluorescence Detection

1985 ◽  
Vol 68 (5) ◽  
pp. 1042-1045
Author(s):  
Ugo R Cieri
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Small Volume ◽  
Steam Bath ◽  
Atropine Sulfate ◽  
Excitation Wavelength ◽  
Fluorescence Detector ◽  
Commercial Sample ◽  
Relative Standard

Abstract A method is presented for the determination of small quantities of atropine in commercial preparations by liquid chromatography (LC) with fluorescence detection. The sample is extracted with CHC13 from basic suspension, the CHC13 is evaporated on the steam bath, and the dry residue is dissolved in a small volume of CH3OH. A reverse phase column is used for the LC analysis; the eluting solvent is prepared by mixing 950 mL CH3OH with 50 mL water containing 1 g of the sodium salt of l-pentanesulfonic acid. The fluorescence detector is set at an excitation wavelength of 255 nm and an emission wavelength of 285 nm. Several commercial tablets and injections containing atropine in combination with other ingredients and a commercial sample of belladonna extract were analyzed by the proposed method. Recoveries of atropine sulfate from aqueous solutions averaged 100.7% with a relative standard deviation (RSD) of 3.35% for atropine sulfate levels of 0.12 mg. Recoveries of atropine sulfate from synthetic injection formulations were 99.8 and 100.0% withRSDsof 2.03and2.35%, respectively; the atropine sulfate concentrations of commercial injections with the same formulations were found to be 97.0 and 100.0% of the labeled amounts with RSDs of 0.53 and 1.46%, respectively

scholarly journals An Accurate and Reproducible Method for the Quantitative Analysis of Isoflavones and Their Metabolites in Rat Plasma Using Liquid Chromatography/Mass Spectrometry Combined with Photodiode Array Detection

2006 ◽  
Vol 89 (4) ◽  
pp. 1158-1167 ◽  
Author(s):  
Estatira Sepehr ◽  
Patrick Robertson ◽  
G Sarwar Gilani ◽  
Gerard Cooke ◽  
Benjamin Pui-Yan Lau
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Rat Plasma ◽  
Biochanin A ◽  
Array Detector ◽  
Plasma Samples ◽  
Simple Method ◽  
Potential Health ◽  
Relative Standard ◽  
Photodiode Array

Abstract To study the safety and potential health benefits of soy isoflavones, a rapid and simple method based on liquid chromatography combined with mass spectrometry (LC/MS) and photodiode array detector (PDA) was developed for the determination of isoflavones in rat plasma. The analytes included daidzein, genistein, glycitein, equol, 4-ethyl phenol, and biochanin A over a concentration range of 1.04320.0 nM using 75 L of rat plasma. Rat plasma samples were hydrolyzed by adding an enzyme mixture from Helix pomatia containing glucuronidase and sulfatase to convert the isoflavone -glycosides daidzin, genistin, and glycitin to their active aglycone forms. A liquidliquid extraction method using ethyl acetate as the extraction solvent was used to extract aglycones and the internal standards (phenolphthalein -d glucuronide, 4-methylumbelliferyl sulfate, and apigenin) from digested plasma samples. The extract was evaporated to dryness under a nitrogen stream, reconstituted with 0.1%formic acid in wateracetonitrile (85 + 15), and injected into a Zorbax SB-CN reversed-phase column (4.6 75 mm, 3.5 m particle size). The Micromass ZQ detector was operated in the positive ion selected-ion monitoring mode. The flow rate for LC was 1.0 mL/ min, with a split where 25% of the effluent was introduced into the electrospray ionization probe of the MS instrument and 75% into the PDA. The chromatographic run time was 16.0 min, with delay of 10 min/injection. The interday precision and accuracy of the standard samples were <2.6% relative standard deviation and <10% relative error, respectively. Recovery of the reported isoflavones with this method varied from 86 to 100%.

Alcohol Determination by HPLC with Postcolumn Derivatization Based on the Thiosulfate-catalyzed Reaction of Alcohols and Cerium(IV) and Fluorescence Detection of Cerium(III)

2020 ◽  
Vol 16 ◽  
Author(s):  
Ikko Mikami ◽  
Eri Shibayama ◽  
Kengo Takagi
Keyword(s):  
Detection Limit ◽  
Fluorescence Detection ◽  
Reaction Rate ◽  
Detection Method ◽  
Fluorescence Detector ◽  
Reaction Solution ◽  
Optimum Detection ◽  
Postcolumn Derivatization ◽  
Sensitive Method

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

Development and Validation of a New Method for the Determination of Anti-hepatitis C Agent Simeprevir in Human Plasma using HPLC with Fluorescence Detection

2020 ◽  
Vol 16 (4) ◽  
pp. 428-435
Author(s):  
Ahmed F.A. Youssef ◽  
Yousry M. Issa ◽  
Kareem M. Nabil
Keyword(s):  
Hepatitis C ◽  
Human Plasma ◽  
Fluorescence Detection ◽  
Internal Standard ◽  
Protein Precipitation ◽  
Assay Method ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
Relative Standard

Background: Simeprevir is one of the recently discovered drugs for treating hepatitis C which is one of the major diseases across the globe. Objective: The present study involves the development of a new and unique High-Performance Liquid Chromatography (HPLC) method using fluorescence detection for the determination of simeprevir (SIM) in human plasma. Methods: Two methods of extractions were tested, protein precipitation using acetonitrile and liquidliquid extraction. A 25 mM dipotassium hydrogen orthophosphate (pH 7.0)/ACN (50/50; v/v), was used as mobile phase and C18 reversed phase column as the stationary phase. The chromatographic conditions were optimized and the concentration of simeprevir was determined by using the fluorescence detector. Cyclobenzaprine was used as an internal standard. Results: Recovery of the assay method based on protein precipitation was up to 100%. Intra-day and inter-day accuracies range from 92.30 to 107.80%, with Relative Standard Deviation (RSD) range 1.65-8.02%. The present method was successfully applied to a pharmacokinetic study where SIM was administered as a single dose of 150 mg SIM/capsule (Olysio®) to healthy individuals. Conclusion: This method exhibits high sensitivity with a low limit of quantification 10 ng mL-1, good selectivity using fluorescence detection, wide linear application range 10-3000 ng mL-1, good recovery and highly precise and validation results. The developed method can be applied in routine analysis for real samples.

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