Application of a Developed Method for the Extraction of Triazines in Surface Waters and Storage Prior to Analysis to Seawaters of Galicia (Northwest Spain)

A simple method based on solid-phase extraction combined with liquid chromatography for simultaneous determination of nine triazine herbicides (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine, and terbutryn) in surface water samples was developed and validated. Under optimized conditions, 50 mL of water sample was pumped through the Oasis HLB cartridge, and triazines were eluted with 3 mL acetone. Finally the extract was concentrated to dryness, reconstituted with 1 mL methanol : water (1 : 1) and injected into the HPLC-DAD system. The stability of the herbicides on the cartridges at −18 and 4°C was also evaluated, and the recoveries obtained after three weeks of storage were satisfactory for all compounds. The analytical features of the proposed method were satisfactory: repeatability and intermediate precision were <10% and recoveries in spiked river water and seawater samples were higher than 93% for all compounds studied. Limits of quantification (varied from 0.46 to 0.98 µg L−1) were adequately allowing the determination of these compounds at the levels requested by the 2008/105/EC Directive. Finally, this method was applied to the analysis of 50 seawater samples from Galicia (northwest Spain).

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Determination of Bisphenol A in Milk and Dairy Products by High-Performance Liquid Chromatography with Fluorescence Detection

Journal of Food Protection ◽

10.4315/0362-028x-66.8.1439 ◽

2003 ◽

Vol 66 (8) ◽

pp. 1439-1443 ◽

Cited By ~ 42

Author(s):

JEONG-HUN KANG ◽

FUSAO KONDO

Keyword(s):

Bisphenol A ◽

Dairy Products ◽

High Performance ◽

Solid Phase ◽

Skim Milk ◽

The European Union ◽

Condensed Milk ◽

Oasis Hlb ◽

Milk And Dairy Products

This study was conducted to develop a selective and sensitive method for the determination of bisphenol A (BPA) levels in milk and dairy products. A method based on solvent extraction with acetonitrile and solid-phase extraction (SPE) was developed for the analysis of BPA in milk, yogurt, cream, butter, pudding, condensed milk, and flavored milk, and a method using two SPE cartridges (OASIS HLB and Florisil cartridge) for skim milk was also developed. The developed methods showed good recovery levels (77 to 102%) together with low detection limits (1 μg/liter for milk, yogurt, pudding, condensed milk, flavored milk, and skim milk and 3 μg/liter for cream and butter). These methods are simple, sensitive, and suitable for the analysis of BPA in milk and dairy products. When 40 milk and dairy products were analyzed by the proposed methods, BPA was not identified in noncanned products, but its levels ranged from 21 to 43 μg/kg in canned products, levels that were 60- to 140-fold lower than the migration limits in the European Union and Japan.

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A Method for Determination of Penicillin G Residue in Waste Penicillium chrysogenum Using High Performance Liquid Chromatography

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.768.15 ◽

2015 ◽

Vol 768 ◽

pp. 15-24

Author(s):

Pu Wang ◽

Hui Ling Liu ◽

Bing Wang ◽

Xiu Wen Cheng ◽

Qing Hua Chen ◽

...

Keyword(s):

Penicillium Chrysogenum ◽

High Performance ◽

Extraction Process ◽

Single Step ◽

Penicillin G ◽

Selective Method ◽

Extraction Solvent ◽

Oasis Hlb ◽

Optimized Conditions

In this study, a rapid and selective method has been developed to determine PENG residues in waste penicillium chrysogenum by using SPE cleanup strategy followed by HPLC. Furthermore, some parameters which influenced the extraction efficiency including extraction mode, solvent and time, while washing solution and eluting solution for SPE were systematically investigated. It should be noted that the extraction process was carried out in a single step by mixing the extraction solvent acetonitrile: formic acid in aqueous solution and chrysogenum samples under ultrasound. The SPE procedure was conducted using Oasis HLB as the clean up cartridge, n-hexane as washing solution, and mixture of acetonitrile and methanol as eluting solution. Under the optimized conditions, the linear of PENG are in the range of 0.1-2000 μg/mL, with the correlation was R2>0.99. In addition, the recoveries of PENG in these samples at three fortification levels of 800-1800mg/kg were 74.98% to 113.47% are obtained, respectively. Moreover, a limits of detection (0.006 mg/kg) and quantification (0.02 mg/kg) could be achieved.

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Multiresidue Determination of Organophosphorus Pesticides in Ginkgo Leaves by Accelerated Solvent Extraction and Gas Chromatography with Flame Photometric Detection

Journal of AOAC International ◽

10.1093/jaoac/88.3.729 ◽

2005 ◽

Vol 88 (3) ◽

pp. 729-735

Author(s):

Xionghai Yi ◽

Yitong Lu

Keyword(s):

Gas Chromatography ◽

Solvent Extraction ◽

Solid Phase ◽

Organophosphorus Pesticides ◽

Accelerated Solvent Extraction ◽

Simple Method ◽

Photometric Detection ◽

Relative Standard ◽

Flame Photometric Detection

Abstract A rapid and simple method using accelerated solvent extraction and solid-phase extraction cleanup was developed and validated for the determination of 15 organophosphorus pesticides in ginkgo leaves by capillary gas chromatography with flame photometric detection. The pesticides were extracted at 100°C under 1500 psi pressure in <20 min. The average recovery from 10 g ginkgo leaves, fortified at 3 levels ranging from 0.05 to 1.00 mg/kg, was 95.2% with a relative standard deviation of 4.6%. The limits of detection ranged from 1.11 × 10−3 mg/kg (dimethoate) to 4.44 × 10−3 mg/kg (dichlorvos). The proposed method showed acceptable accuracy and precision while minimizing environmental concerns, time, and labor. Furthermore, the method could be easily applied to the monitoring of these 15 organophosphorus pesticides in ginkgo leaves.

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Nonlinear Dynamics of a Spar Platform

Volume 1: 24th Conference on Mechanical Vibration and Noise, Parts A and B ◽

10.1115/detc2012-70384 ◽

2012 ◽

Author(s):

Elvidio Gavassoni ◽

Paulo Batista Gonçalves ◽

Deane M. Roehl

Keyword(s):

Asymptotic Methods ◽

Weather Conditions ◽

Gas Production ◽

Spar Platform ◽

Highly Nonlinear ◽

Oil And Natural Gas ◽

The Stability ◽

Floating Platforms ◽

And Storage

Spar floating platforms have been largely used for deep water drilling, oil and natural gas production and storage of these fluids. In extreme weather conditions such structures may exhibit a highly nonlinear dynamic behavior. In this paper a 2-DOF model is used to study the heave and pitch coupled response in free and forced vibration. Special attention is given to the determination of the nonlinear vibration modes (NNMs). Non-similar and similar NNMs are obtained analytically by direct application of asymptotic methods and the results show important NNM features such as instability and multiplicity of modes. The NNMs are used to generate reduced order models that consist of 1-DOF nonlinear oscillators. It facilitates the parametric analysis and the derivation of important features of the system such as the frequency-amplitude relation associated to each nonlinear mode and resonance curves. The stability is analyzed by the Floquet theory. Bifurcation diagrams and Mathieu charts are used to identify the unstable regions in the force parameter space. The analytical results show good agreement with the numerical solution obtained by direct integration of the equation of motion.

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Simultaneous Analysis of Simple Coumarins and Furocoumarines in Cigarettes by Solid-Phase Extraction with Gas Chromatography-Mass Spectrometry

Journal of AOAC International ◽

10.5740/jaoacint.16-0192 ◽

2017 ◽

Vol 100 (5) ◽

pp. 1559-1564 ◽

Cited By ~ 3

Author(s):

Yang Zheng ◽

Xiuli Xu ◽

Fei Yuan ◽

Meiyi Yao ◽

Shunli Ji ◽

...

Keyword(s):

Mass Spectrometry ◽

Gas Chromatography ◽

Solid Phase Extraction ◽

Solid Phase ◽

Gas Chromatography Mass Spectrometry ◽

Phase Extraction ◽

Selected Ion Monitoring ◽

Oasis Hlb ◽

Coumarin 6

Abstract A sensitive, high-throughput analytical method based on a GC-MS method was established for the simultaneous quantitative determination of two categories of harmful coumarins: simple coumarins (coumarin, 6-methylcoumarin, 7-methoxycoumarin, 3,4-dihydrocoumarin, and 7-ethoxy-4-methylcoumarin) and furocoumarines (psoralen, 8-methoxypsoralen, 5-methoxypsoralen, and trioxysalen). The nine analytes were extracted with ethyl acetate, purified with Oasis HLB solid-phase extraction (SPE) cartridges, and identified and quantitatively determined by GC-MS in selected-ion monitoring mode. The LODs and LOQs of these compounds were in the ranges of 12.5–21.2 and 41.6–70.0 μg/kg, respectively. Average recoveries for the nine analytes ranged from 72.7 to 86.6% atLOQ, 1.5× LOQ, and 2× LOQ spike levels, with RSDs that were typically lower than 5.1%. TheSPE-GC-MS method developed in this study was initially applied to research coumarins in cigarette samples; it proved to be accurate, sensitive, convenient, and practical.

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