Improvement of methods for analysing sucrose acetate isobutyrate (SAIB) in soft drinks using GC-FID and evaluating antioxidant effects in the SAIB emulsion system.

Sucrose acetate isobutyrate SAIB (E444) is a mixture produced by the esterification of sucrose with acetic anhydride and isobutyric anhydride. It is a food additive that is used as an emulsifier in soft drinks. It is difficult to analyse SAIB quantitatively because there are 256 synthesisable structures in the mixture. This study developed an analytical method for SAIB using gas chromatography-flame ionization detection (GC-FID). The pre-treatment of SAIB in soft drinks was performed using a liquid-liquid extraction method, which demonstrated a recovery rate of 107.8 ± 7.2%. In the GC-FID analysis of SAIB, numerous peaks were observed in the chromatogram, and the content of SAIB was calculated as the sum of these peak areas. A series of analytical methods were validated according to International Conference for Harmonization (ICH) guidelines. Accordingly, the applicability of the developed analytical method was confirmed for both domestic and imported soft drinks distributed in Korea. Additionally, in the linoleic acid emulsion, SAIB exhibited better lipid oxidation stability than the natural antioxidant α-tocopherol and had similar efficacy to the synthetic antioxidant butylated hydroxytoluene (BHT). Although SAIB has excellent lipid oxidation stability, it must be used within legal standards according to consumer demand to reduce the use of synthetic materials in processed foods. The validated GC-FID analytical method will enable subsequent monitoring of the distributed products.

Sensing Precursors of Illegal Drugs-Rapid Detection of Acetic Anhydride Vapors at Trace Levels Using Photoionization Detection and Ion Mobility Spectrometry.

Sensitive real-time detection of vapors produced by the precursors, reagents and solvents used in the illegal drugs manufacture represents a priority nowadays. Acetic anhydride (AA) is the key chemical used as acetylation agent in producing the illegal drugs heroin and methaqualone. This study was directed towards quick detection and quantification of AA in air, using two fast and very sensitive analytical techniques: photoionization detection (PID) and ion mobility spectrometry (IMS). Results obtained indicated that both PID and IMS can sense AA at ultra-trace levels in air, but while PID produces a non-selective response, IMS offers richer information. Ion mobility spectrometric response in the positive ion mode presented one product ion, at reduced ion mobility K0 of 1.89 cm2 V-1 s-1 (almost overlapped with positive reactant ion peak), while in the negative ion mode two well separated product ions, with K0 of 1.90 and 1.71 cm2 V-1 s-1, were noticed. Our study showed that by using a portable, commercial IMS system (model Mini IMS, I.U.T. GmbH Berlin) AA can be easily measured at concentrations of 0.05 ppmv (0.2 mg m-3) in negative ion mode. Best selectivity and sensitivity of the IMS response were therefore achieved in the negative operation mode.

Improvement of simultaneous determination of neutral monosaccharides and uronic acids by gas chromatography.

Although pre-column derivatization with n-propylamine and acetic anhydride combined with the gas chromatograph was a useful method for the analysis of monosaccharide composition, failure often occurs because of lack of detail information on the mechanism as well as the operating key point in derivatization process. In this study, the key points in the derivatization (lactonization time, the amount of n-propylamine and acetic anhydride) were investigated and optimized to improve the method. Under the optimal conditions, the derivatives of seven neutral monosaccharides and two uronic acids were simultaneouly obtained, after which they were well separated and detected by GC. It was also found that all derivatives of monosaccharides were stable even stored for 20days. The linearity, sensitivity, precision, reproducibility and recovery rate of the improved method were evaluated. Thereafter, five polysaccharide samples from different sources were analyzed to validate the improved method.

Mass Spectrometric Approaches to the Identification of Potential Ingredients in Cigarette Smoke Causing Cytotoxicity.

Cigarette smoke contains many harmful chemicals that contribute to the pathogenesis of smoking-related diseases such as chronic obstructive pulmonary disease, cancer, and cardiovascular disease. Many studies have been done to identify cytotoxic chemicals in cigarette smoke and elucidate the onset of the above-mentioned diseases caused by smoking. However, definitive mechanisms for cigarette smoke toxicity remain unknown. As candidates for cytotoxic chemicals, we have recently found methyl vinyl ketone (MVK) and acetic anhydride in nicotine/tar-free cigarette smoke extract (CSE) using L-tyrosine (Tyr), an amino acid with highly reactive hydroxyl group. The presence of MVK and acetic anhydride in CSE was confirmed by gas chromatography-mass spectrometry (GC/MS). We also found new reaction products formed in B16-BL6 mouse melanoma (B16-BL6) cells treated with CSE using LC/MS. These were identified as glutathione (GSH) conjugates of α,ß-unsaturated carbonyl compounds, MVK, crotonaldehyde (CA), and acrolein (ACR), by the mass value and product ion spectra of these new products. ACR and MVK are type-2 alkenes, which are well known as electron acceptors and form Michael-type adducts to nucleophilic side chain of amino acids on peptides. These α,ß-unsaturated carbonyl compounds may have a key role in CSE-induced cell death.

Exposure to cyclic anhydrides in welding: a new allergen-chlorendic anhydride.

Respiratory effects associated with welding fumes have been manifested in welders as occupational asthma. Previous studies have concerned mainly the effects of metal fume exposure, although it has also been suggested that asthma may develop as a result of exposure to contaminants generated from painted metals. To determine whether welding fumes contain irritating and sensitizing anhydrides, air samples were collected during the repair welding of forest harvesters, which were painted with chlorinated polyester paint. Samples were collected with an assembly of a spiral glass trap inserted between a filter holder with a Teflon filter and a Tenax sampling tube. Sample analyses were with GC-MS and GC-ECD. Sensitizing anhydrides released from the paint into the air were primarily chlorendic anhydride (<2-44 microg/m(3)) and phthalic anhydride (11-21 microg/m(3)). Hydrogen chloride (HCl) and hexachlorocyclopentadiene were also found. Airborne HCl was measured with Dräger tubes. Since paint films are electrical insulators, the film around the welding seam was removed before arc welding. Removal of paint with an abrasive wheel caused the least exposure to HCl (<0.5 ppm) in contrast to burning with a gas fuel torch, (HCl approximately 5 ppm). HCl exposure was the highest (<0.5-20 ppm) during welding. It is recommended that dry paint coating be removed from an area around the seam with an abrasive wheel, not by burning, before welding.

Determination of some histamine H1-receptor antagonists in dosage forms.

Three simple and accurate methods are presented for determination of Cetirizine, Fexofenadine, Loratadine and Acrivastine in pure form and commercial dosage forms. The first method is based on the reaction of the above cited drugs with bromocresol purple dye to form ion-pair complex extractable with chloroform and subsequently measured spectrophotometrically. Secondly, eosin gives with these drugs ion-pair complex, measurable directly without extraction both spectrophotometrically and spectrofluorimetrically. The last method involves the base-catalysed condensation of mixed anhydrides of organic acids (citric acid/acetic anhydride) where as the tertiary amino group in the above-cited drugs acts as the basic catalyst. The product of condensation is measured spectrophotometrically. All the reaction conditions for the proposed methods have been studied.

Determination of aliphatic anhydrides and acids by reversed-phase liquid chromatography.

Few chromatography methods have been reported for the determination of anhydrides in mixtures or as mixed anhydrides. The potential reactivity of anhydrides with water and other common eluent components complicates possible schemes for separation and analysis. By optimizing variables that affect hydrolysis, including the stationary phase, conditions can be found to successfully analyze anhydrides as reactive as acetic anhydride. The corresponding acids can be determined at the same time. The effect of the stationary phase on anhydride hydrolysis rates may prove to be a sensitive means of probing stationary phase chemistry.

Fatal poisoning with detajmium: identification of detajmium and its metabolites and artifacts by gas chromatography-mass spectrometry and quantification by high-performance liquid chromatography.

After ingestion of an unknown dose of detajmium, a 14-year-old female collapsed with asystolia. Resuscitation efforts were not successful. A medicolegal autopsy was carried out, and blood, liver and gastric content were extracted and analyzed by gas chromatography-mass spectrometry (GC-MS). After derivatization with acetic anhydride, detajmium and twelve of its derivatives and metabolites were identified. The main metabolic pathways include hydroxylation and subsequent O-methylation of the indol ring, and oxidation as well as reduction of the C-21 hydroxyl function. Cleavage of the N-alkyl side-chain is a further, possibly non-enzymatic degradation pathway. Artifact formation induced by acetylation included dehydratation of the hydroxyl function of C-21 and the N-alkyl side-chain. The detajmium concentration in blood of the decreased was determined by high-performance liquid chromatography with fluorimetric detection (12 micrograms/ml).

Monitoring airborne reactive chemicals by derivatization and high performance thin layer chromatography--anhydrides, acid halides, isocyanates.

A versatile reagent-coated solid sorbent tube has been developed for monitoring airborne reactive chemicals--including acetic anhydride (AcAn), chloroacetyl chloride (CAC), and isocyanatoethyl methacrylate (IEM). The monitoring procedures involve simultaneous collection and derivatization of these chemicals using the reagent 1-(2-pyridyl)piperazine. Following tube/pump sampling, the derivatives are solvent desorbed and analyzed by high performance thin layer chromatography (HPTLC). HPTLC offers high sample throughout chromatographic analyses. The methods are designed to provide accurate time-weighted-average (TWA) and short-term excursion measurements. The reactivity of anhydrides, acid halides, and isocyanates preclude long-term collection without derivatization. Formation of the derivative immediately stabilizes the molecules allowing retention on the solid sorbent. In addition, the derivative allows good chromatography and provides high detection sensitivity. The recoveries for acetic anhydride, chloracetyl chloride and isocyanatoethyl methacrylate are 97.5, 95.2 and 85.0%, respectively. Validation also included the evaluation of humidity effects, storage effects, and potential interferences.

Sampling and analysis of acetic anhydride in air.

This paper describes the development of a new method for monitoring acetic anhydride in the presence of acetic acid in the occupational environment. The method consisted of collecting airborne acetic anhydride on a solid sorbent, desorbing it with acetone and analyzing it by gas chromatography. During the development of this method various parameters such as selection of column, selection of solid sorbent, selection of desorber solvent, effects of humidity, flow rate, total sample volume, desorption efficiency, and shelf-life of samples were studied. Interference from methyl acetate, water, formic acid, and acetic acid was also tested with the determination of acetic anhydride.