scholarly journals Simultaneous determination of acetaldehyde, ethyl acetate, methanol, iso butanol, and iso almyacol concentrations in white alcol in some areas in Hai Duong province in 2018 - 2019

2020 ◽  
Vol 3 (3) ◽  
pp. 196-203
Author(s):  
Hoang Nguyen Duc ◽  
Canh Tran Quang ◽  
◽  
Keyword(s):  
Ethyl Acetate ◽  
Simultaneous Determination ◽  
Proficiency Test ◽  
Isoamyl Alcohol ◽  
Test Results ◽  
Isobutyl Alcohol ◽  
Methanol Content ◽  
Z Scores ◽  
The Relationship

The research has developed a method for simultaneous determination of acetaldehyde, ethyl acetate, methanol, isobutyl alcohol, isoamyl alcohol in white alcohol. Validation results show that the method has satisfactory accuracy with recovery in the range of 105 - 108%, repeatability RSD < 1.57%, detection limit below 3 mg/L for all compounds. Proficiency test results in 2020 were satisfactory with Z-scores of all substances below 2. The method has been applied to analyze 200 distilled alcohol samples and 50 blended alcohol samples taken in Hai Duong city during the period from 2018 to 2020. Three of 200 distilled alcohol samples have the methanol content higher than the maximum limit. The relationship between methanol content in proportion to content of acetaldehyde, ethyl acetate, isobutyl alcohol, and isoamyl alcohol in the same sample has been evaluated to distinguish between blended alcohol and distilled alcohol.

scholarly journals Spectrodensitometric simultaneous determination of esomeprazole and domperidone in human plasma

2017 ◽  
Vol 15 (1) ◽  
pp. 293-298
Author(s):  
Pakinaz Y. Khashaba ◽  
Hassan Refat H. Ali ◽  
Mohamed M. El-Wekil
Keyword(s):  
Ethyl Acetate ◽  
Factorial Design ◽  
Simultaneous Determination ◽  
Human Plasma ◽  
Mobile Phase ◽  
Fractional Factorial Design ◽  
Cost Effective ◽  
Fractional Factorial ◽  
Tlc Plates

AbstractA simple, rapid, cost-effective, and sensitive TLC-spectrodensitometric method for simultaneous determination of esomeprazole and domperidone was developed and tested in human plasma. Ethyl acetate: methanol: benzene: acetonitrile (5: 4: 8: 3, v/v/v/v) mobile phase was used for separation on TLC plates detected at 286 nm. The linearity ranges were 5-1200 and 2-600 ng/ spot for esomeprazole and domperidone, and limits of detection were 1.73 and 0.59 ng/spot. The effects of four variables affecting Rf were evaluated by fractional factorial design. The benzene volume and saturation time had significant effects.

scholarly journals Determination of Residues of Flumequine and 7-Hydroxyflumequine in Edible Sheep Tissues by Liquid Chromatography with Fluorimetric and Ultraviolet Detection

1998 ◽  
Vol 81 (3) ◽  
pp. 519-527 ◽  
Author(s):  
Jean-michel Delmas ◽  
Anne-marie Chape ◽  
Pascal Sanders
Keyword(s):  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Simultaneous Determination ◽  
Rapid Method ◽  
Active Metabolite ◽  
Fluorimetric Detection ◽  
Ultraviolet Detection ◽  
Tissue Extracts ◽  
Edible Tissues

abstract A simple, sensitive, and rapid method for simultaneous determination of residues of flumequine and its microbiologically active metabolite 7-hydroxyflumequine in 100 mg sheep edible tissues (muscle, liver, kidney, and fat) by liquid chromatography is reported. After liquid-liquid cleanup with ethyl acetate, tissue extracts were injected onto a Select B column. The 2 compounds were determined by ultraviolet and fluorimetric detection. The method was repeatable and reproducible for flumequine and 7-hydroxyflumequine in muscle, liver, kidney, and fat, with limits of detection below 2 and 3 μg/kg for flumequine and 7-hydroxyflumequine, respectively. Mean recoveries for flumequine were 90 ± 7, 82 ± 7,89 ± 5, and 82 ± 6% in muscle, liver, kidney, and fat, respectively. Mean recoveries for 7-hydroxyflumequine were 91 ± 2, 90 ± 4, 86 ± 3, and 84 ± 4% in muscle, liver, kidney, and fat, respectively.

scholarly journals Simultaneous Determination of Residual Antiparasitic Lactones in Bovine Muscle and Liver by Liquid Chromatography with Fluorescence Detection

2003 ◽  
Vol 86 (3) ◽  
pp. 490-493 ◽  
Author(s):  
Tomoko Nagata ◽  
Fumio Miyamoto ◽  
Yasuyuki Hasegawa ◽  
Eiichi Ashizawa
Keyword(s):  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Simultaneous Determination ◽  
Fluorescence Detection ◽  
Dimethyl Formamide ◽  
Bovine Muscle

Abstract Abamectin, doramectin, eprinomectin, ivermectin, milbemectin, and moxidectin in bovine muscle and liver were extracted with acetonitrile. The extracts were partitioned with n-hexane and then evaporated to dryness. The residue was cleaned up on Bond Elute NH2 cartridge, and the drugs were eluted from the cartridge with methanol–ethyl acetate (3 + 7). The eluate was evaporated to dryness, and residues were derivatized with N,N-dimethyl-formamide–acetic anhyride-1-methylimidazole. The derivatives were determined by liquid chromatography with fluorescence detection. Recoveries of the 6 drugs were 79.6–63.8% in muscle and 71.6–60.6% in liver at 0.01 ppm levels. The quantitation limits were 5 ppb for each drug.

Laboratory performance and regulatory requirements.

1987 ◽  
Vol 33 (6) ◽  
pp. 1087-1102 ◽  
Author(s):  
M L Kenney
Keyword(s):  
Linear Regression ◽  
Proficiency Test ◽  
Clinical Laboratory ◽  
Group Practice ◽  
Federal Regulations ◽  
Test Results ◽  
Regulatory Requirements ◽  
Service Levels ◽  
Z Scores ◽  
Log Normal

Abstract We compared performance levels of four clinical laboratory groups defined by federal regulatory characteristics, to assess the appropriateness of selected regulations: laboratories in JCAH-accredited hospitals; non-doctoral-directed independent laboratories; state-regulated but federally exempt group-practice laboratories; and unregulated laboratories in physicians' offices (POLs). Federal regulations evaluated were those dealing with the doctoral directorship requirement and exemption of POLs from regulation. Quantitative analytes were compared by using linear regression on log-normal transformations of mean absolute-z scores of proficiency test results. The scope of services offered by laboratories was statistically related to performance in quantitative analytes. Confounding effects of scope-of-service levels were statistically controlled. Proportions of errors in qualitative analytes were compared. No pattern of statistically discernible differences in performance was found between hospital laboratories and non-doctoral-directed laboratories. Both regulated non-doctoral-directed laboratories and state-regulated but federally exempt group-practice laboratories demonstrated higher levels of performance than unregulated POLs.

Liquid Chromatographic Determination of Simazine, Atrazine, and Propazine Residues in Catfish

1995 ◽  
Vol 78 (4) ◽  
pp. 1067-1071 ◽  
Author(s):  
David C Holland ◽  
Robert K Munns ◽  
José E Roybal ◽  
Jeffrey A Hurlbut ◽  
Austin R Long
Keyword(s):  
Ethyl Acetate ◽  
Petroleum Ether ◽  
Simultaneous Determination ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Triazine Herbicides ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the simultaneous determination of the triazine herbicides, simazine (SIM), atrazine (ATZ), and propazine (PRO) in the 12.5–100 ppb range in catfish. The herbicides are extracted from catfish homogenates with ethyl acetate, followed by solvent partitioning between acetonitrile and petroleum ether and additional cleanup on a C18 cartridge. A Supelcosil LC-18-DB column is used for LC separation, and UV determination is at 220 nm. The isocratic mobile phase is a mixture of methanol, acetonitrile, and water. Mean recoveries from catfish were 88.7, 96.9, and 91.7%; standard deviations were 6.84,7.78, and 6.26%; and coefficients of variation were 7.72,8.03, and 6.82% for SIM, ATZ, and PRO, respectively.

Rapid Method for the Simultaneous Determination of Six Ionophores in Feed by Liquid Chromatography/Mass Spectrometry

2012 ◽  
Vol 95 (4) ◽  
pp. 1016-1022 ◽  
Author(s):  
Daljit Vudathala ◽  
Lisa Murphy
Keyword(s):  
Simultaneous Determination ◽  
Proficiency Test ◽  
Ammonium Acetate ◽  
Atmospheric Pressure Chemical Ionization ◽  
Liquid Chromatography Mass Spectrometry ◽  
Highly Sensitive ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical ◽  
Certified Values

Abstract A simple and highly sensitive LC/MS method was developed for the simultaneous determination of six ionophores—lasalocid, monensin, laidlomycin, maduramycin, salinomycin, and narasin—in feed. The procedure involved extraction of 1 g of feed with 4 mL of methanol–water (9 + 1, v/v) by shaking on a platform shaker for 45 min. After centrifugation, the extracts were diluted with methanol–water (75 + 25, v/v) and analyzed without any cleanup. The analysis was performed on a Betasil C18 column (150 × 4.6 mm id, 5 μm particle size) connected to an LC/MS system operated in the atmospheric pressure chemical ionization (APCI) mode. We believe this to be the first method that uses the APCI mode for the analysis of ionophores. The mobile phase consisted of 50 mM ammonium acetate as solvent A and acetonitrile–methanol (7 + 3, v/v) as solvent B in a gradient run. Excellent recoveries of 81–120% were found for all compounds at fortification levels of 1–200 μg/g, with RSD ≤15% (except 17% for maduramycin at 2 and 5 μg/g, and 16% for salinomycin at 1 μg/g). At 0.5 μg/g, recoveries of 87–119% were obtained, with RSD ≤20%. However, recovery of lasalocid was 133% and salinomycin 79% in sow and horse feed, respectively. Average RSD values of lasalocid and salinomycin were 22 and 21%, respectively. Finally, proficiency test samples analyzed with the method demonstrated favorable agreement with the certified values.

scholarly journals The determination of fatigue limits under alternating stress conditions

1914 ◽  
Vol 90 (620) ◽  
pp. 411-425 ◽  
Keyword(s):  
Infinite Number ◽  
Fatigue Tests ◽  
Test Results ◽  
Railway Company ◽  
Standard Of Comparison ◽  
The Subject ◽  
Pull Tests ◽  
Push And Pull ◽  
The Relationship

In the year 1867 A. Wöhler, locomotive superintendent of a railway company in Berlin, exhibited at the Paris Exhibition the results of some experiments on the endurance of metals, and was thereupon engaged by the Prussian Government to carry out the more exhaustive enquiry into this subject with which his name is always associated. The results of his labours were published in 1871, and were highly appreciated, but few additional experiments were made until the subject was again taken up successively by Sir Benjamin Baker, Reynolds and Smith, Rogers, Stanton and bairstow, Eden, Rose and Cunningham, and Prof. Hopkinson. All these experiments are confined either to fatigue bending or to push and pull tests, using only steel or iron, whereas the present ones include a large number of torsion fatigue tests on various metals. Until comparatively recently there was no satisfactory standard of comparison for fatigue tests, the determination of the asymptote or limiting fatigue stress for an infinite number of revolutions from a few irregular test results leading to very uncertain conclusions, so much so that by some it was considered very doubtful whether there were any real fatigue limits, while others adopted as standards of comparison the fatigue stresses which would cause fractures at the millionth repetition. The first problem which had to be investigated was therefore to ascertain the relationship between the intensities of fatigue stresses and the numbers of repetitions of these stresses which would cause fracture; and, should this relationship be found to indicate the existence of a limiting stress for an infinite number of revolutions, or more briefly of a fatigue limit, then the next step would have to be its exact determination.

scholarly journals Penetapan Kadar Flavonoid Total Ekstrak Etanol Biji Pinang (Areca catechu L.) Menggunakan Metode AlCl3

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Agitya Resti Erwiyani ◽  
Dina Sihot Rejeki Gultom ◽  
Dian Oktianti
Keyword(s):  
Ethyl Acetate ◽  
Colorimetric Method ◽  
Betel Nut ◽  
Standard Curve ◽  
Areca Catechu ◽  
Qualitative Test ◽  
Quercetin Concentration ◽  
The Relationship ◽  
Curve Equation

Pinang merupakan tanaman yang banyak tersedia di Indonesia dan memiliki berbagai manfaat. Pemanfaatan air rebusan biji pinang digunakan masyarakat dalam membersihkan dan menyembuhkan luka infeksi. Biji pinang mengandung senyawa fenolik seperti flavonoid, tannin, asam galat, katekin, beta-sitosterol, gum dan asam amino. Biji pinang dilakukan purifikasi untuk mengilangkan zat ballast yang tidak dibutuhkan. Penelitian ini bertujuan untuk menetapkan kadar flavonoid total ekstrak kasar dan ekstrak terpurifikasi. Metode yang digunakan dalam penetapan kadar adalah metode kolorimetri AlCl3. Penetapan kadar flavonoid dilakukan pada panjang gelombang 413,5 nm dengan standar baku pembanding kuersetin. Plot hubungan antara konsentrasi kuersetin versus absorbansi diperoleh persamaan kurva baku sebesar y = 0,0088x – 0,17 dengan nilai R2 sebesar 0,9998. Uji kualitatif menunjukkan ekstrak biji pinang tanpa purifikasi, dengan perlakuan purifikasi n-heksan dan etil asetat mengandung metabolit sekunder diantaranya flavonoid, saponin, tannin dan fenol. Purifikasi pelarut n-heksan didapatkan hasil rendemen lebih banyak dibandingkan ekstrak yang dipurifikasi dengan pelarut etil asetat. Kadar flavonoid ekstrak tanpa purifikasi, ekstrak purifikasi pelarut n-heksan dan etil asetat berturut – turut sebesar 69,13 ; 130,3 ; dan 94,73 mgQE/g. Hal tersebut sebanding dengan perolehan % rendemen tertinggi diperoleh dari ekstrak terpurifikasi n-heksan. Purifikasi pada ekstrak akan menyebabkan hilangnya zat ballast dalam ekstrak sehingga kandungan flavonoid pada ekstrak akan lebih tinggi.Kata kunci : flavonoid, metode AlCl3, ekstrak, purifikasiAreca nut is a plant that is widely available in Indonesia and has various benefits. Utilization of boiled betel nut water is used by the community to clean and heal infected wounds. Betel nuts contain phenolic compounds such as flavonoids, tannins, gallic acid, catechins, beta-sitosterol, gum, and amino acids. Areca seeds are purified to remove unnecessary ballast substances. This study aims to determine the total flavonoid levels of crude extract and purified extract. The method used in the assay is the AlCl3 colorimetric method. Determination of flavonoid levels was carried out at a wavelength of 413.5 nm with a quercetin standard. The plot of the relationship between quercetin concentration versus absorbance obtained a standard curve equation of y = 0.0088x - 0.17 with an R2 value of 0.9998. The qualitative test showed that betel nut extract without purification, with purification treatment of n-hexane and ethyl acetate, contained secondary metabolites including flavonoids, saponins, tannins, and phenols. The purification of the n-hexane solvent obtained more yields than the extract purified with ethyl acetate solvent. The flavonoid levels of the extract without purification, the purified extract of n-hexane and ethyl acetate were 69.13; 130.3; and 94.73 mg QE / g. This is comparable to the highest% yield obtained from purified extracts of n-hexane. Purification of the extract will cause the loss of ballast substances in the extract so that the flavonoid content in the extract will be higher.Keywords: flavonoids, AlCl3 method, extract, purification

Collaborative Study of the Quantitative Determination of Fusel Oil and Ethyl Acetate by Gas-Liquid Chromatography

1968 ◽  
Vol 51 (4) ◽  
pp. 915-921
Author(s):  
Richard L Brunelle
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Ethyl Acetate ◽  
Simultaneous Determination ◽  
Collaborative Study ◽  
Gas Liquid Chromatography ◽  
Fusel Oil ◽  
Preliminary Work ◽  
Standard Deviations

Abstract Thirteen chemists representing twelve laboratories participated in a collaborative study for the quantitative determination of ethyl acetate and fusel oil by GLC. The results on four samples containing various amounts of ethyl acetate and fusel oil were compared with the official AOAC procedures. For all samples, the standard deviations were lower with GLC. Collaborators preferred the GLC procedure because the simultaneous determination of ethyl acetate and n-propyl, iso-butyl, and isoamyl alcohols is possible. Results from preliminary work performed on the quantitative determination of acetaldehyde by GLC were encouraging. It is recommended that the proposed GLC procedure for the quantitative determination of ethyl acetate and fusel oil be adopted as official, first action, and that work be continvied on the determination of acetaldehyde by GLC.

scholarly journals TLC-spectrodensitometric method for simultaneous determination of dapagliflozin and rosuvastatin in rabbit plasma: stability indicating assay and kinetic studies

RSC Advances ◽  
2020 ◽  
Vol 10 (67) ◽  
pp. 40795-40805
Author(s):  
Noha S. Abbas ◽  
Sayed M. Derayea ◽  
Mahmoud A. Omar ◽  
Gamal A. Saleh
Keyword(s):  
Ethyl Acetate ◽  
Simultaneous Determination ◽  
Mobile Phase ◽  
Kinetic Studies ◽  
Urine Samples ◽  
Plasma Stability ◽  
Rabbit Plasma ◽  
Stability Indicating ◽  
Plasma And Urine Samples

Mixtures of DAPA and ROSV were separated using ethyl acetate : methanol (5 : 0.1 v/v) as mobile phase and applied in plasma and urine samples in addition to stability indicating and kinetic studies.

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