scholarly journals Acetic acid and ethyl acetate in Madeira wines: Evolution with ageing and assessment of the odour rejection threshold

2017 ◽  
Vol 32 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Andreia Miranda ◽  
Vanda Pereira ◽  
Marisela Pontes ◽  
Francisco Albuquerque ◽  
José C. Marques
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Rejection Threshold

Interlaboratory comparison of results of erythrocyte protoporphyrin analysis.

1978 ◽  
Vol 24 (12) ◽  
pp. 2135-2138 ◽  
Author(s):  
K W Jackson
Keyword(s):  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Ethyl Acetate ◽  
Disease Control ◽  
Whole Blood ◽  
Interlaboratory Comparison ◽  
Direct Reading ◽  
Blood Samples ◽  
Erythrocyte Protoporphyrin ◽  
Whole Blood Samples

Abstract Each of 65 laboratories analyzed 10 whole-blood samples for erythrocyte protoporphyrin by one or more of several analytical procedures. These procedures were of two types: (a) extraction of protoporphyrin from the erythrocytes into ethyl acetate/acetic acid, re-extraction into hydrochloric acid, and fluorometric measurement; or (b) direct reading in a portable fluorometer (hematofluorometer), with no pretreatment of the blood sample. Interlaboratory correlation was generally poor, especially between laboratories using extraction procedures. Hematofluorometric results intercorrelated better, but they had a low bias as compared to the extraction approach. Nationwide standardization of the test is required to assure satisfactory interlaboratory performance and to identify laboratories whose results are sufficiently accurate to be used for interpretations according to guidelines set forth by the Center for Disease Control for erythrocyte protoporphyrin testing.

HSCCC Separation of Three Main Compounds from the Crude Extract of Dracocephalum Tanguticum by Using Dimethyl Sulfoxide as Cosolvent

2020 ◽  
Author(s):  
Xue Yang ◽  
Yongling Liu ◽  
Tao Chen ◽  
Nana Wang ◽  
Hongmei Li ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Efficient Method ◽  
Crude Extract ◽  
High Speed ◽  
Glacial Acetic Acid ◽  
Butyl Alcohol ◽  
Preparative Hplc ◽  
Counter Current

Abstract Separation of natural compounds directly from the crude extract is a challenging work for traditional column chromatography. In the present study, an efficient method for separation of three main compounds from the crude extract of Dracocephalum tanguticum has been successfully established by high-speed counter-current chromatography (HSCCC). The crude extract was directly introduced into HSCCC by using dimethyl sulfoxide as cosolvent. Ethyl acetate/n-butyl alcohol/0.3% glacial acetic acid (4: 1: 5, v/v) system was used and three target compounds with purity higher than 80% were obtained. Preparative HPLC was used for further purification and three target compounds with purity higher than 98% were obtained. The compounds were identified as chlorogenic acid, pedaliin and pedaliin-6″-acetate.

scholarly journals Exposure Studies of Different Kinds of Volatile Organic Compounds in Vapour Phase with a Narrow-gap Cell Containing CuxS Modified Carbon Microdisc Electrode

2018 ◽  
Vol 63 (1) ◽  
pp. 170-178 ◽  
Author(s):  
László Kiss
Keyword(s):  
Acetic Acid ◽  
Volatile Organic Compounds ◽  
Ethyl Acetate ◽  
Organic Compounds ◽  
Modified Electrode ◽  
Vapour Phase ◽  
Narrow Gap ◽  
Current Increase ◽  
Interelectrode Gap ◽  
Volatile Organic

In this article, the feasibility of the CuxS modified carbon microdisc electrode was examined by exposure to four different volatile organic compounds (2-propanol, acetic acid, ethyl acetate and n-butylamine) directly in their vapour phase using cyclic voltammetry and amperometry. The performance of the modified microdisc was compared with the bare carbon microdisc (30 μm in diameter) which was involved in a narrow-gap cell. By using both methods high current increase was observed for 2-propanol with the modified electrode and its sensitivity was sufficiently higher than with the bare electrode. The modified electrode showed lower current signals in case of acetic acid and n-butylamine. The latter formed a condensation layer at the interelectrode gap. Neither the bare nor the modified electrode was sensitive to ethyl acetate.

Erythrocyte porphyrin analysis in the detection of lead poisoning in children: evaluation of four micromethods.

1976 ◽  
Vol 22 (2) ◽  
pp. 161-168 ◽  
Author(s):  
T L Hanna ◽  
D N Dietzler ◽  
C H Smith ◽  
S Gupta ◽  
H S Zarkowsky
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Lead Poisoning ◽  
Complete Recovery ◽  
Comparison Method ◽  
Working Standard ◽  
Single Extraction ◽  
Double Extraction ◽  
Poisoning In Children

Abstract We evaluated four procedures for determination of erythrocyte porphyrin: double extraction with ethyl acetate/acetic acid-HCl, single extraction with ethanol, single extraction with acetone, and direct solubilization with detergent-buffer. The ethyl acetate procedure, when used with two portions of HCl, apparently gives complete recovery of porphyrin and is suitable for reference as a comparison method. The ethanol procedure gives a high and consistent recovery and is technically simpler. The acetone procedure gives low and variable recovery of porphyrin, and the detergent-buffer method is subject to serious hemoglobin interference; neither of these two procedures offers any technical advantage. Stability of samples and methods for standardization were explored. A procedure for expressing results in terms of erythrocyte Zn-protoporphyrin content is given. Because of its stability, coproporphyrin is useful as a daily working standard. The ethyl acetate and ethanol methods are about equally efficient for detecting lead intoxication. Because of its simplicity, the ethanol method seems to be the best for use in screening.

Zum stoffwechsel von aromaten, II. über die muconsäurespaltung von einfachen o-diphenolen / on the metabolism of aromatic compounds, ii * the muconic acid scission of simple o-diphenols

1973 ◽  
Vol 28 (11-12) ◽  
pp. 662-674 ◽  
Author(s):  
Günther Schulz ◽  
Erich Hecker
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Ethyl Acetate ◽  
Peracetic Acid ◽  
Aromatic Compounds ◽  
Time Course ◽  
Protocatechuic Acid ◽  
Uv Light ◽  
Steric Effects ◽  
Muconic Acid

Abstract The preparation of substituted cis,cis-muconic acids by oxidative ring scission of simple o-di-phenols with peracetic acid is investigated. Scission of pyrocatechol (1) to cis,cis-muconic acid (2) gives optimal yields, if acetic acid or ethyl acetate is used as solvent and if the solution is 15-20% with respect to sulfuric acid free peracetic acid comprising a one molar excess of oxidant. Under similar conditions, 3-tosylamino-pyrocatechol yields with peracetic acid the hitherto unknown α-tosylamino-cis,cis-muconic caid (18). 18 may be converted to α-tosylamino-traras,trans-muconic acid (19) by means of iodine, UV light or heating. From protocatechuic acid (4) under similar conditions not β-carboxy-cis,cis-muconic acid (5) is obtained, but rather β-carboxy-mucono-lactone (6 b, γ-carboxymethyl-β-carboxy-Δα-butenolide). As yet, this lactone has been accessible only from an isomer of β-carboxy-cis,cis-muconic acid, the latter being obtainable by enzymatic scission of protocatechuic acid (4). Steric effects are responsible for both, the formation of the free cis,cis-muconic acids 2 and 18 from pyrocatechol (1) and α-tosylamino-pyrocatechol, and the formation of the γ-lactone 6 b instead of β -carboxy-cis,cis-muconic acid by scission of protocatechuic acid (4). The time course of the reactions shows that - compared to pyrocatechol (1) - a 3-tosylamino-group enhances the peracetic acid scission, whereas a 4-carboxygroup as in 4 slows it down

Liquid-liquid equilibrium of acetic acid – ethanol – ethyl acetate – water quaternary system: Data review and new results at 323.15 K and 333.15 K

2020 ◽  
Vol 503 ◽  
pp. 112321 ◽  
Author(s):  
Maya Trofimova ◽  
Alexey Sadaev ◽  
Artemiy Samarov ◽  
Alexandra Golikova ◽  
Nikita Tsvetov ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Quaternary System ◽  
Liquid Equilibrium ◽  
System Data

High-Pressure Liquid Chromatographic Method for the Determination of Patulin in Apple Butter

1975 ◽  
Vol 58 (4) ◽  
pp. 754-756 ◽  
Author(s):  
George M Ware
Keyword(s):  
High Pressure ◽  
Acetic Acid ◽  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Chromatographic Method ◽  
High Pressure Liquid Chromatographic ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract Patulin is extracted from apple butter samples with ethyl acetate and the extract is cleaned up on a silica gel column, using benzene-ethyl acetate (75+25) as the eluant. High-pressure liquid chromatography, using a 25 cm Zorbax-Sil column, isooctane-ethyl ether-acetic acid (750+250+0.5) as the mobile solvent, and a 254 nm ultraviolet detector, is used for the determinative step. Under these conditions, patulin is eluted before 5-hydroxymethylfurfural, a component of apple butter which interferes with other liquid chromatographic and thin layer chromatographic methods. Recoveries of patulin added at levels of 34.6, 138.4, and 276.8 μg/kg ranged from 89.0 to 112.1%.

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