Determination Of Volatile Organic Acids Research Articles

Rapid determination of volatile organic acids in edible salt and high-salinity food by direct analysis in real time mass spectrometry

A simple method based on direct analysis in real time combined with quadrupole time-of-flight mass spectrometry was developed to determine five volatile organic acids (i.e., butyric acid, isovaleric acid, cyclopentanecarboxylic acid, isocaproic acid and cyclohexanecarboxylic acid). Various samples relative to organic acids were investigated, including 45 edible salts and 18 high-salinity foods (curing food, marinated meat and sauce). These volatile organic acids obtained good linearity results (R2 > 0.9907) in the range of 0.5–50 μg/mL. The limits of detection were 0.4–1.0 μg/g, and the limits of quantification were 0.9–3.1 μg/g. The process efficiency of five organic acids were ranging between 81 and 114%. Taking advantage of the salt-tolerant characteristic of DART, the sample preparation process could be simpler than traditional method. Only a few minutes were required owning to the absence of liquid chromatography. As the results of real sample screening, butyric acid, isovaleric acid and cyclopentanecarboxylic acid were found in 15 commercial samples, including 13 edible salts and 2 high-salinity foods.

Microwave-assisted synthesis of porphyrin conjugated microporous polymers for microextraction of volatile organic acids in tobaccos

Conjugated microporous polymers (CMPs) with permanent microporosity and extended p-conjugated skeletons have recently shown the fascinating application in separation and enrichment. In this report, porphyrin CMP that possessed microporous structure and nitrogen-rich pyrrole building blocks was successfully synthesized by microwave-assisted method. Then, a novel coating based on porphyrin CMP was fabricated on silica fiber for efficient enrichment volatile organic acids (VOAs). The simulation showed the coating exhibited strong interaction with volatile organic acids based on charge transfer interaction, hydrogen bond and size effect. Hence, we proposed a method for determination of volatile organic acids in tobaccos by headspace solid-phase microextraction (HS-SPME) with porphyrin CMP coating by gas chromatography-mass spectrometry. The results showed that the coating provided high enrichment factors for VOAs ranging from 66,657 to 133,970 and low limits of detection from 4.6 to 22 ng/L. A good linearity was observed for propionic acid and crotonic acid ranging from 0.050 to 8.0 μg/L, 2-methylheptanoic acid ranging from 0.063 to 1.5 μg/L, others ranging from 0.025 to 3.0 μg/L with the determination coefficient (R2) between 0.9900 and 0.9980. The strategy for determination of volatile compounds in complex solid samples was successfully applied to the analysis of volatile organic acids in tobacco leaves. The results showed that the method was accurate and reliable.

Extraction and determination of volatile organic acid concentration in pomegranate, sour cherry, and red grape juices by PPy-Ag nanocomposite fiber for authentication

ABSTRACTA solid phase microextraction fiber based on nano-sized polypyrrole-Ag (PPy-Ag) was fabricated. The size and morphology of PPy-Ag particles was characterized by scanning electron microscopy (SEM). A method based on PPy-Ag-SPME-gas chromatography (GC) was developed for determination of sour cherry and grape juice adulteration in pomegranate juice samples by determination of volatile organic acids (VOAs) concentration. The VOAs of pomegranate juice (valeric, isovaleric, lactic, and acetic acids) were extracted by fabricated polypyrrole-Ag fiber, and the concentration of VOAs was determined by GC analysis. The effects of pomegranate juice (PJ) percent, sour cherry juice (SCJ) percent, and red grape juice (GJ) percent as three variable factors on the concentration of VOAs were studied. Box Behnken Design (BBD) was applied to design the experiments that study the effect of factors on the VOAs concentration. The results showed that sour cherry and grape juice adulteration in pomegranate juice can affect the VOAs concentration, and there is a good relation between pomegranate, sour cherry, and grape juice percent and VOAs concentration. So the presented analytical method is a suitable and fast method for determination of pomegranate juice authentication.

Determination of volatile organic acids in tobacco by single‐drop microextraction with in‐syringe derivatization followed by GC‐MS

In this work, the novel technique based on headspace single-drop microextraction with in-syringe derivatization followed by GC-MS was established to determine the volatile organic acids in tobacco. The parameters for headspace single-drop microextraction and in-syringe derivatization were optimized, including extraction time, and volume of derivatization reagent and in-syringe derivatization time. The method validations including linearity, precision, recovery and LOD were also studied. The obtained results illustrated that the optimized technique was easy, highly efficient and sensitive. Finally, the proposed method was successfully applied to the analyses of volatile organic acids in tobacco samples with seven different brands. It was further demonstrated that the present technique developed in this study does offer a simple and fast approach to determine volatile organic acids in tobacco.

Determination of volatile organic acids in oriental tobacco by needle-based derivatization headspace liquid-phase microextraction coupled to gas chromatography/mass spectrometry

A method coupling needle-based derivatization headspace liquid-phase microextraction with gas chromatography–mass spectrometry (HS-LPME/GC–MS) was developed to determine volatile organic acids in tobacco. The mixture of N, O-bis(trimethylsilyl)trifluoroacetamide and decane was utilized as the solvent for HS-LPME, resulting that extraction and derivatization were simultaneously completed in one step. The solvent served two purposes. First, it pre-concentrated volatile organic acids in the headspace of tobacco sample. Second, the volatile organic acids extracted were derivatized to form silyl derivatives in the drop. The main parameters affecting needle-based derivatization HS-LPME procedure such as extraction and derivatization reagent, microdrop volume, extraction and derivatization time, and preheating temperature and preheating time were optimized. The standard addition approach was essential to obtain accurate measurements by minimizing matrix effects. Good linearity ( R 2 ≥ 0.9804) and good repeatability (RSDs ≤ 15.3%, n = 5) for 16 analytes in spiked standard analytes sample were achieved. The method has the additional advantages that at the same time it is simple, fast, effective, sensitive, selective, and provides an overall profile of volatile organic acids in the oriental tobacco. This paper does offer an alternative approach to determine volatile organic acids in tobacco.

Determination of organic acids (C1-C10) in the atmosphere, motor exhausts, and engine oils

A method is described for the determination of volatile organic acids in the atmosphere, motor exhausts, and engine oils. Atmospheric organic acids were collected on a KOH impregnated quartz filter and derivatized to p-bromophenacyl esters. The derivatives were analyzed by high-resolution capillary gas chromatography and gas chromatography-mass spectrometry. C/sub 1/-C/sub 10/ aliphatic organic acids and benzoic acid were detected in Los Angeles air. Acetic and formic acids are dominant followed by propionic acids. Total concentrations measured were 0.37-7.45 ppb. Organic acids (C/sub 1/-C/sub 10/) were also detected in the motor exhaust from a single automobile at idle conditions and showed that the distribution of individual acids was similar to that in the air, but the concentration was 17 times higher than for the average atmospheric content. Formic, acetic, and benzoic acids were detected as major species of used engine oil, but their content is negligible in new oil.

Capillary gas chromatography determination of volatile organic acids in rain and fog samples

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCapillary gas chromatography determination of volatile organic acids in rain and fog samplesKimitaka. Kawamura and Isaac R. KaplanCite this: Anal. Chem. 1984, 56, 9, 1616–1620Publication Date (Print):August 1, 1984Publication History Published online1 May 2002Published inissue 1 August 1984https://doi.org/10.1021/ac00273a018RIGHTS & PERMISSIONSArticle Views584Altmetric-Citations106LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (570 KB) Get e-Alerts Get e-Alerts

Gas-Liquid Chromatographic Determination of Volatile Organic Acids as Benzyl Esters with Applications to Tuna, Shrimp, and Eggs

Abstract Volatile acids are recognized as useful indicators of decomposition in a variety of foods. A method has been developed for the rapid preparation of benzyl esters of formic, acetic, propionic, isobutyric, and butyric acids and for their quantitative determination by gas-liquid chromatography. Esters were formed by reaction with BCl3-benzyl alcohol, followed by washing with aqueous ammonia before storage. They were chromatographed, using tetradecane as an internal standard, and were separated at 140°C on columns having DC-200 and SP-1000 as liquid phases. The method offers significant advantages, especially for the determination of formic acid, over the present official AOAC method, 17.042-17.046. Recoveries of volatile acids added to steam distillates of tuna extracts were ≥ 91% with mean recoveries for the 5 volatile acids of 96—104%. Applications to the analysis of canned tuna, frozen headless shrimp, and frozen whole egg resulted in recoveries of ≥ 8 2% with mean recoveries for the 5 acids of 91—101%. The method was compatible with an automated gas chromatograph-data processing system.

Direct analytical procedure for determination of volatile organic acids in raw municipal wastewater

A direct analytical method for identification and determination of the individual volatile acids in raw sewage was developed. The proposed procedure is rapid, omitting tedious sample pretreatment and thus avoiding possible losses involved in steam distillation, evaporation or extraction. It consists of direct injection of raw sewage into a gas chromatograph, including Carbowax 20 M on acid washed Chromosorb W column and a flame ionization detector. Sample preparation is confined to addition of solid metaphosphoric acid to the raw sewage, and removal of precipitated proteins and suspended solids by centrifugation. The direct injection method proved to be practicable, accurate and rapid. Volatile acids content in raw municipal sewage in Haifa, Israel, was found to be in the range of 150–160 mg l −1, of which 120–125 mg l −1 was acetic acid, 30–33 mg l −1 propionic acid, 6–8 mg l −1 butyric acid, 2 mg l −1 isovaleric acid, and 0.5–1 mg l −1 valeric acid.

A method for the determination of volatile organic acids in aqueous solutions and urine, and the results obtained in propionic acidaemia, β-methylcrotonylglycinuria and methylmalonic aciduria

A rapid and simple method for the determination of the volatile acidic and neutral substances in aqueous solutions and urine is described and evaluated. The results obtained in the analysis of urine from normal humans and patients with propionic acidaemia, β-methylcrotonylglycinuria and methylmalonic aciduria are presented and discussed.