scholarly journals Poly(4-vinylphenol) coated magnetic nanoparticles based dispersive solid-phase microextraction of the determination of mercury(II) in water

2021 ◽  
Keyword(s):  
Mineral Water ◽  
Magnetic Particles ◽  
Solid Phase ◽  
Correlation Factor ◽  
Limit Of Quantification ◽  
Magnetic Sorbent ◽  
Coating Method ◽  
Optimized Conditions ◽  
Interday Precision

<p>The development of magnetic sorbent for dispersive solid-phase micro-extraction (DmSPE) often requires lengthy multi-step reactions. This research revealed a simplified method for preparing magnetic sorbent for the DmSPE using poly(4-vinylphenol) (PVP). The magnetic sorbent (PVP@MNP) was prepared by coating PVP on magnetic particles (MNP). The characterization and formation of PVP@MNP were confirmed using infrared spectroscopy, scanning electron microscope, and energy-dispersive X-ray spectroscopy. The primary goal of this study is to develop a sensitive DmSPE method to analyze Hg2+ in water using PVP@MNP as a magnetic sorbent. The preparation of PVP@MNP was performed in a simple coating method at room temperature. Briefly, the PVP@MNP was prepared by sonicating the mixture of MNP and PVP. This sorbent was then used as a magnetic sorbent for the extraction of Hg2+ from water. The developed PVP@MNP based DmSPE reached a low method of detection limit (0.01 μg L-1) and limit of quantification (0.04 μg L-1). This method also showed a wide linearity range (100 - 2000 µg L-1) with a good correlation factor under optimized conditions. The developed method showed good recovery (72-90%) with good intraday and interday precision. This study also showed that the developed DmSPE method was effectively used to determine Hg2+ in drinking water, mineral water, and surface water. The result also demonstrated that PVP@MNP is reusable.</p>

LC–MS-MS Method for the Determination of Antidepressants and Benzodiazepines in Meconium

2020 ◽  
Vol 44 (6) ◽  
pp. 580-588
Author(s):  
A López-Rabuñal ◽  
E Lendoiro ◽  
M Concheiro ◽  
M López-Rivadulla ◽  
A Cruz ◽  
...  
Keyword(s):  
Extraction Efficiency ◽  
Solid Phase ◽  
Gradient Methods ◽  
Reversed Phase ◽  
Process Efficiency ◽  
Limit Of Quantification ◽  
Mode 2 ◽  
Positive Mode ◽  
Compound Method

Abstract An LC–MS-MS method for the determination of 14 benzodiazepines (BZDs) (alprazolam, α-hydroxyalprazolam, clonazepam, bromazepam, diazepam, nordiazepam, lorazepam, lormetazepam, oxazepam, flunitrazepam, 7-aminoflunitrazepam, triazolam, midazolam and zolpidem) and 15 antidepressants (ADs) (amitriptyline, nortriptyline, imipramine, desipramine, clomipramine, norclomipramine, fluoxetine, norfluoxetine, sertraline, norsertraline, paroxetine, venlafaxine, desmethylvenlafaxine, citalopram and desmethylcitalopram) in meconium was developed and validated. Meconium samples (0.25 ± 0.02 g) were homogenized in methanol and subjected to mixed-mode cation exchange solid-phase extraction. Chromatographic separation was performed in reversed phase, with a gradient of 0.1% formic acid in 2 mM ammonium formate and acetonitrile. Two different chromatographic gradient methods were employed, one for the separation of ADs and another for BZDs. Analytes were monitored by tandem mass spectrometry employing electrospray positive mode in MRM mode (2 transitions per compound). Method validation included: linearity [n = 5, limit of quantification (LOQ) to 400 ng/g], limits of detection (n = 6, 1–20 ng/g), LOQ (n = 9, 5–20 ng/g), selectivity (no endogenous or exogenous interferences), accuracy (n = 15, 90.6–111.5%), imprecision (n = 15, 0–14.6%), matrix effect (n = 10, −73 to 194.9%), extraction efficiency (n = 6, 35.9–91.2%), process efficiency (n = 6, 20.1–188.2%), stability 72 h in the autosampler (n = 3, −8.5 to 9%) and freeze/thaw stability (n = 3, −1.2 to −47%). The method was applied to four meconium specimens, which were analyzed with and without hydrolysis (enzymatic and alkaline). The authentic meconium samples tested positive for alprazolam, α-hydroxyalprazolam, clonazepam, diazepam, nordiazepam, fluoxetine, norfluoxetine, clomipramine and norclomipramine. Therefore, the present LC–MS-MS method allows a high throughput determination of the most common BZDs and ADs in meconium, which could be useful in clinical and forensic settings.

scholarly journals Determination of 77 Multiclass Pesticides and Their Metabolitesin Capsicum and Tomato Using GC-MS/MS and LC-MS/MS

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1837
Author(s):  
Harischandra Naik Rathod ◽  
Bheemanna Mallappa ◽  
Pallavi Malenahalli Sidramappa ◽  
Chandra Sekhara Reddy Vennapusa ◽  
Pavankumar Kamin ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
Graphitized Carbon Black ◽  
Limit Of Quantification ◽  
Gas And Liquid Chromatography ◽  
Relative Standard ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Primary Secondary Amine

A quick, sensitive, and reproducible analytical method for the determination of 77 multiclass pesticides and their metabolites in Capsicum and tomato by gas and liquid chromatography tandem mass spectrometry was standardized and validated. The limit of detection of 0.19 to 10.91 and limit of quantification of 0.63 to 36.34 µg·kg−1 for Capsicum and 0.10 to 9.55 µg·kg−1 (LOD) and 0.35 to 33.43 µg·kg−1 (LOQ) for tomato. The method involves extraction of sample with acetonitrile, purification by dispersive solid phase extraction using primary secondary amine and graphitized carbon black. The recoveries of all pesticides were in the range of 75 to 110% with a relative standard deviation of less than 20%. Similarly, the method precision was evaluated interms of repeatability (RSDr) and reproducibility (RSDwR) by spiking of mixed pesticides standards at 100 µg·kg−1 recorded anRSD of less than 20%. The matrix effect was acceptable and no significant variation was observed in both the matrices except for few pesticides. The estimated measurement uncertainty found acceptable for all the pesticides. This method found suitable for analysis of vegetable samples drawn from market and farm gates.

scholarly journals Quantitative Determination of Azithromycin in Human Plasma by Liquid Chromatography–Mass Spectrometry and its Application in Pharmackokinetic Study

2012 ◽  
Vol 11 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Maizbha Uddin Ahmed ◽  
Mohammad Safiqul Islam ◽  
Tasmin Ara Sultana ◽  
AGM Mostofa ◽  
Muhammad Shahdaat Bin Sayeed ◽  
...  
Keyword(s):  
Mobile Phase ◽  
Solid Phase ◽  
Internal Standard ◽  
Extraction Process ◽  
Serum Samples ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Linear Concentration Range ◽  
Linear Concentration

Azithromycin is an effective and well-known antimicrobial agent. In the present study, a simple, sensitive and specific LC/MS/MS method has been developed and validated for the quantification of Azithromycin in  human serum samples using Clarithromycin as internal standard. Azithromycin was extracted from biological matrix  by using solid phase extraction process. The chromatographic separation was performed on Luna C18 (3 ?, 2x150   mm) column with a mobile phase consisting of 35 mM ammonium acetate buffer (mobile phase-A) and acetonitrile  and methanol in ratio of 90:10 ( as mobile phase-B) at a flow rate of 0.25 mL/min. The method was validated over a  linear concentration range of 0.5?50.0 ng/mL and limit of quantification (LOQ) was 0.5 ng/mL with a coefficient of  correlation (r2) = 0.9998. The intra-day and inter-day precision expressed as relative standard deviation were 1.64% – 8.43% and 2.32% – 9.92%, respectively. The average recovery of azithromycin from serum was 98.11%. The method  was successfully applied to a pharmacokinetic study after oral administration of Azithromycin 200 mg/5 ml suspension in healthy Bangladeshi volunteers. DOI: http://dx.doi.org/10.3329/dujps.v11i1.12488 Dhaka Univ. J. Pharm. Sci. 11(1): 55-63, 2012 (June)

scholarly journals Oxytetracycline Residues in Honey Analyzed by Liquid Chromatography with UV Detection

2013 ◽  
Vol 57 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Anna Gajda ◽  
Andrzej Posyniak ◽  
Andrzej Bober ◽  
Tomasz Błądek ◽  
Jan Żmudzki
Keyword(s):  
Liquid Chromatography ◽  
Oxalic Acid ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Experimental Treatment ◽  
Uv Detection ◽  
Limit Of Quantification ◽  
Chromatography Method ◽  
Liquid Chromatography Method

Summary A liquid chromatography method with UV detection for determination of oxytetracycline (OTC) in honey has been developed. The samples were extracted with the solution of oxalic acid. The clean-up procedure was performed by solid phase extraction (SPE) using polymeric Strata X and carboxylic acid cartridges. Chromatographic separation was carried out on the Luna C8 analytical column with mobile phase consisting of acetonitrile-0.02 M oxalic acid. The method has been successfully validated according to the requirements of the European Decision 2002/657/EC and this method is used in routine control of oxytetracycline in honey samples. The limit of detection (LOD) and limit of quantification (LOQ) of the presented method were 10 and 12.5 μg/kg, respectively. The developed method has also been verified in quantitative determination of oxytetracycline residues in honey after experimental treatment with this product in bee colonies.

scholarly journals Rapid and Sensitive Method for Quantitative Determination of Lopinavir and Ritonavir in Human Plasma by Liquid Chromatography- Tandem Mass Specrtometry

2009 ◽  
Vol 6 (1) ◽  
pp. 223-230 ◽  
Author(s):  
G. A. Temghare ◽  
S. S. Shetye ◽  
S. S. Joshi
Keyword(s):  
Liquid Chromatography ◽  
Human Plasma ◽  
Solid Phase ◽  
Internal Standard ◽  
Therapeutic Monitoring ◽  
Tandem Mass ◽  
Limit Of Quantification ◽  
Liquid Chromatography Tandem Mass ◽  
Sensitive Method

A rapid and sensitive liquid chromatography-mass spectrometric (LC-MS-MS) method for the simultaneous determination of lopinavir and ritonavir in human plasma using abacavir as internal standard has been developed and validated. Sample preparation of plasma involved solid phase extraction. Detection was performed using an Applied Biosystems Sciex API 2000 Mass spectrometer. The assay of lopinavir and ritonavir was linear over the range of 50 ng mL-1to 20000 ng mL-1and 20 ng mL-1to 3000 ng mL-1 respectively with a precision of <15% and accuracy in the range of 85-115%. The limit of quantification in plasma for lopinavir and ritonavir was 50 ng mL-1and 20 ng mL-1respectively. The described method has the advantage of being rapid and easy and it could be applied in therapeutic monitoring of these drugs in human plasma

Preconcentration and Determination of Lead by Solidification of Floated Organic Drop Coupled with Nanodrop Spectrophotometry

2013 ◽  
Vol 829 ◽  
pp. 825-830 ◽  
Author(s):  
Ali Mazloomifar ◽  
Nafiseh Khatibi
Keyword(s):  
Sea Water ◽  
Chelating Agent ◽  
Limit Of Quantification ◽  
Liquid Phase Microextraction ◽  
Relative Standard ◽  
Preconcentration Factor ◽  
Uv Visible ◽  
Optimized Conditions ◽  
Sample Vial

The liquid-phase microextraction based on solidification of floating organic microdrop coupled with UV-visible spectrophotometer for preconcentration and determination of lead in the aqueous samples has been developed. In this technique, 20μL of 1-undecanol containing dithizone as the chelating agent (10-3mol L-1) was transferred to the water samples containing lead ions, and the solution was stirred for 25 min. The sample vial was cooled in an ice bath for 5 min. The solidified extract was transferred into a conical vial where it melted immediately, and then the organic phase was analyzed by Nanodrop spectrophotometer. Factors that influence the extraction and complex formation, such as pH, concentration of dithizone, extraction time, effect of ionic strenght, temperature and stirring rate were optimized. Under the optimized conditions, a preconcentration factor of 356, detection limit of 0.006 μgL-1, limit of quantification 0.018 μgL-1and a good relative standard deviation of 2.1% were obtained. The procedure was applied to sea water, mineral water and well water.

scholarly journals Determination of Flumorph Residues in Vegetables, Soil, and Natural Water by Solid-Phase Extraction Cleanup and High-Performance Liquid Chromatography with UV Detection

2008 ◽  
Vol 91 (6) ◽  
pp. 1459-1466 ◽  
Author(s):  
Ji-Ye Hu ◽  
Yu-Chao Zhang ◽  
Hai Yan
Keyword(s):  
Solid Phase Extraction ◽  
Natural Water ◽  
High Performance ◽  
Solid Phase ◽  
Residue Analysis ◽  
Reversed Phase ◽  
Uv Detection ◽  
Phase Extraction ◽  
Limit Of Quantification

Abstract A method for high-performance liquid chromatographic (HPLC) determination of flumorph residues in cucumber, tomato, soil, and natural water was developed and validated. Primary secondary amine or octadecylsilyl (C18) solid-phase extraction cartridges were used for sample preparation. Reversed-phase HPLC with UV detection was used for separation and quantification of the pesticide. The combined cleanup and chromatographic method steps were sensitive and reliable for simultaneous determination of residues of the 2 isomers of flumorph in the studied samples. This method is characterized by recovery &gt;97.9, coefficient of variation &lt;6.2, and limit of quantification of 0.01 mg/kg, in agreement with directives for method validation in residue analysis. Flumorph residues in the samples were further confirmed by HPLC/mass spectrometry. The proposed method is fast, easy to perform, and could be used for monitoring of pesticide residues.

scholarly journals A simple spectrophotometric method for the determination of methyldopa using p-chloranil in the presence of hydrogen peroxide

2008 ◽  
Vol 33 (3) ◽  
pp. 7-12 ◽  
Author(s):  
M. A. Gotardo ◽  
L. S. Lima ◽  
R. Sequinel ◽  
J. L. Rufino ◽  
L. Pezza ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Pharmaceutical Formulations ◽  
Limit Of Quantification ◽  
Coefficients Of Variation ◽  
The Common ◽  
Interday Precision ◽  
Sensitive Spectrophotometric Method

A simple, rapid and sensitive spectrophotometric method has been developed for the determination of methyldopa in pharmaceutical formulations. The method is based on the reaction between tetrachloro-p-benzoquinone (p-chloranil) and methyldopa, accelerated by hydrogen peroxide (H2O2), producing a violet-red compound (λmax = 535 nm) at ambient temperature (25.0 ± 0.2 ºC). Experimental design methodologies were used to optimize the measurement conditions. Beer's law is obeyed in a concentration range from 2.10 x 10-4 to 2.48 x 10-3 mol L-1 (r = 0.9997). The limit of detection was 7.55 x 10-6 mol L-1 and the limit of quantification was 2.52 x 10-5 mol L-1. The intraday precision and interday precision were studied for 10 replicate analyses of 1.59 x 10-3 mol L-1 methyldopa solution and the respective coefficients of variation were 0.7 and 1.1 %. The proposed method was successfully applied to the determination of methyldopa in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in the formulations. The results obtained by the proposed method were favorably compared with those given by the Brazilian Pharmacopoeia procedure at 95 % confidence level.

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