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PubMed1996

Investigation of a pulsed-laser thermo-optical absorbance detector for the determination of food preservatives separated by capillary electrophoresis.

Thermo-optical absorbance (TOA) detection using a KrF excimer waveguide laser for detection of benzoic acid, dehydroacetic acid and sorbic acid separated by capillary electrophoresis (CE) was studied. Detection limits were, on average, ten times better than those for on-column UV absorbance methods with CE, and two or more times better than those for UV absorbance with HPLC. The influence of increased laser power on TOA detection sensitivity was found to be strong for benzoic and dehydroacetic acids but quite weak for sorbic acid. It was discovered that photoisomerization of sorbic acid (2,4-hexadienoic acid) occurred readily in the detection volume at moderate laser powers (P(ave) = 3 mW) and increased with slow electroosmotic flows (< 6 cm/min). The TOA method described here shows improved detection sensitivity for CE analyses of compounds having only weak absorptivities (< 5% of maximum) at lambda = 248 nm, and thus demonstrates its utility for determination of a variety of analytes in a single separation.

Electrophoresis, Capillary↗
PubMed1988

Simultaneous determination of the nine food additives using high-performance liquid chromatography.

A technique for the simultaneous determination of sorbic acid, benzoic acid, dehydroacetic acid, p-hydroxybenzoic acid esters (ethyl, isopropyl, n-propyl, isobutyl and n-butyl p-hydroxybenzoate) and saccharin sodium using ion-pair reversed-phase high-performance liquid chromatography is described. The nine food additives were separated on a Nucleosil 3C18 (3 microns) column (75 x 4.6 mm I.D.) using methanol-acetonitrile-0.05 M aqueous acetonic acid solution (pH 4.5) (1.5:1:3.1) containing 2.5 mM cetyltrimethylammonium chloride as the mobile phase at a flow-rate of 1.0 ml/min, and detected at 233 nm. The food additives were separated within 18 min and their calibration graphs were linear between 2 and 200 ng.

Acetonitriles↗
PubMed2001

Estimation of preservative concentrations in foods and their daily intake based on official inspection results in Japan in fiscal year 1998.

The mean concentration and daily intake of five preservatives were estimated based on the results of an analysis of 89,927 samples of food obtained in official inspections by Japanese local governments in fiscal year 1998. The mean concentration of benzoic acid was 9.5% of the allowable limit, and those of dehydroacetic acid, p-hydroxybenzoic acid, propionic acid, and sorbic acid were 1.5%, 5.7%, 1.7%, and 23.9%, respectively. Daily intake levels of these preservatives per person estimated from the concentration and daily consumption of foods were 6.23 mg, 0.0303 mg, 1.02 mg, 8.10 mg, and 25.0 mg, respectively, and assuming a body weight of 50 kg, the amounts of benzoic acid, p-hydroxybenzoic acid, and sorbic acid consumed were 2.5%, 0.2%, and 2.0% of their acceptable daily intakes, respectively. These values were similar to those obtained based on the results of the official inspections in fiscal years 1994 and 1996.

Benzoic Acid↗
PubMed2004

Optimization by experimental design and artificial neural networks of the ion-interaction reversed-phase liquid chromatographic separation of twenty cosmetic preservatives.

Particular attention are recently receiving antimicrobial agents added as preservatives in hygiene and cosmetics commercial products, since some of them are suspected to be harmful to the human health. The preservatives used belong to different classes of chemical species and are generally used in their mixtures. Multi-component methods able to simultaneously determinate species with different chemical structure are therefore highly required in quality control analysis. This paper presents an ion interaction RP-HPLC method for the simultaneous separation of the 20 typical antimicrobial agents most used in cosmetics and hygiene products, that are: benzoic acid, salicylic acid, 4-hydroxybenzoic acid, methyl-, ethyl-, propyl-, butyl-, benzyl-benzoate, methyl-, ethyl-, propyl-, butyl-, benzyl-paraben, o-phenyl-phenol, 4-chloro-m-cresol, triclocarban, dehydroacetic acid, bronopol, sodium pyrithione and chlorhexidine. For the development of the method and the optimization of the chromatographic conditions, an experimental design was planned and models were built by the use of artificial neural network to correlate the retention time of each analyte to the variables and their interactions. The neuronal models developed showed good predictive ability and were used, by a grid search algorithm, to optimize the chromatographic conditions for the separation of the mixture.

Chromatography, High Pressure Liquid↗
PubMed1995

Micellar electrokinetic capillary chromatographic determination of artificial sweeteners in low-Joule soft drinks and other foods.

A rapid method for the determination of artificial sweeteners in low-Joule soft drinks and other foods by micellar electrokinetic capillary chromatography (MEKC) is described. Caffeine, benzoic acid and sorbic acid, which are often added to soft drinks, can also be determined with this procedure. The artificial sweeteners, aspartame, saccharin, acesulfame-K, alitame and dulcin, and the other food additives are well separated in less than 12 min using an uncoated fused-silica capillary column with a buffer consisting of 0.05 M sodium deoxycholate, 0.01 M potassium dihydrogenorthophosphate, 0.01 M sodium borate operating at 20 kV. Dehydroacetic acid was used as the internal standard for the determinations. The levels of artificial sweeteners, preservatives and caffeine were in good agreement with those determined by the high-performance liquid chromatographic (HPLC) procedure currently used in our Laboratory. The MEKC procedure has the same order of repeatability, is faster and less costly to operate than the HPLC method.

Beverages↗
PubMed1982

Thermodynamic parameters of molecular complexes in aqueous solution: enthalpy-entropy compensation in a series of complexes of caffeine with beta- naphthoxyacetic acid and drug-related aromatic compounds.

Stability constants and thermodynamic parameters have been evaluated for the complexation reaction in aqueous solution of caffeine with beta-naphthoxy acetic acid. The values were higher than those previously reported for the complexation of other ligands with methyl xanthines. In nearly all aromatic ligands complexing with caffeine and theophylline for which data are available, both entropy and free energy of complexation were linearly related to the enthalpy, giving an isoequilibrium relationship. Salicylamide, sodium benzoate and cis-methyl cinnamate exhibited slight deviations on the delta G-delta H plot; the non-aromatic dehydroacetic acid showed the largest deviation. The isoequilibrium relationship was shown to be valid statistically (349-365 K, caffeine systems; 353-372 K, caffeine and theophylline systems) indicating underlying chemical causation. Thermodynamic equations are presented for analysis of the factor involved, which are attributed to a combination of substrate-ligand interactions and solvent effects. The substrate-ligand overlap area is considered as a common parameter through which the solvent and interaction forces might cooperate to give rise to linearity in the isoequilibrium relationship. The increasingly negative experimental values of the enthalpy and entropy with increase in ligand planar overlap area are discussed in relation to the underlying forces involved in the complexation.

Caffeine↗
PubMed1992

Synthesis and inotropic activity of pyrazolo[4,3-c]pyridine-4-ones and related compounds.

Two series of 3,6-dimethyl-1-phenyl-1H-pyrazolo[4,3-c] pyridine-4-ones (5-9) and 3,6-dimethyl-1-phenyl-1H-pyrazolo[4,3-c] pyridine-4-thiones (11-13) were prepared from dehydroacetic acid as starting material and evaluated for positive inotropic activity in vitro. Moreover, the activity of the synthesized compounds was compared with that of mirlinone as a reference. Among these compounds, the positive inotropic activity of 8a, 11a, and 12 were approximately 1.24, 1.77, and 1.11 times more potent, respectively, than that of mirlinone.

Animals↗
PubMedDate not supplied

[Experimental study of the possible use of sodium dehydroacetate as a food additive].

The results are presented of toxico-hygienic investigations of dehydroacetic acid sodium salt (DHASS) proposed as a food additive. The compound toxicity values have been assessed, and late results of the preservative influence on the body of experimental animals after its oral intake have been studied. An approximate value of daily intake (AVDI) of the compound has been calculated. It has been shown that DHASS cannot be recommended as a food additive because its technologically effective concentrations are significantly higher than AVDI.

Animals↗
PubMed1982

A series of inhibitors of azo dye hepatocarcinogenesis partially reverse the azo dye-induced decrease in liver RNA/DNA ratio.

The DNA and RNA content and the mitotic index were determined in the livers of rats pair-fed for 10 days on a control diet, and diets containing 0.06% 3'-methyl-4-dimethylaminoazobenzene (3'MeDAB), either alone or in combination with the inhibitors of azo dye carcinogenesis acetanilide (0.08%), p-hydroxypropiophenone (PHP, 1%), urea (5%), dehydroacetic acid (DHAA, 0.25%), butylated hydroxytoluene (BHT, 0.3%) and 3-methylcholanthrene (3MC, 0.067%). The liver RNA/DNA ratio was increased in rats fed the 3'MeDAB diet following ingestion of each of the inhibitor plus carcinogen-containing diets. The increases were significant except in the instance of urea. The increase was mainly due to increased RNA content in rats fed 3'MeDAB plus acetanilide, DHAA, BHT and 3MC when compared with rats fed 3'MeDAB alone. In rats fed PHP and 3'MeDAB, an increase in total liver DNA that was noted in rats fed 3'MeDAB alone did not take place, while total liver RNA content was similar in both groups; the RNA/DNA ratio was therefore greater in rats protected from 3'MeDAB carcinogenesis by PHP. The results are discussed in relationship to the effects of carcinogens on RNA forming genes and the role of the nucleolus in cell differentiation.

Acetanilides↗
PubMed2000

Simultaneous determination of sweeteners and preservatives in preserved fruits by micellar electrokinetic capillary chromatography.

A micellar electrokinetic capillary method for the simultaneous determination of the sweeteners dulcin, aspartame, saccharin, and acesulfame-K and the preservatives sorbic acid; benzoic acid; sodium dehydroacetate; and methyl-, ethyl-, propyl-, isopropyl-, butyl-, and isobutyl-p-hydroxybenzoate in preserved fruits is developed. These additives are ion-paired and extracted using sonication followed by solid-phase extraction from the sample. Separation is achieved using a 57-cm fused-silica capillary with a buffer comprised of 0.05 M sodium deoxycholate, 0.02 M borate-phosphate buffer (pH 8.6), and 5% acetonitrile, and the wavelength for detection is 214 nm. The average recovery rate for all sweeteners and preservatives is approximately 90% with good reproducibility, and the detection limits range from 10 to 25 microg/g. Fifty preserved fruit samples are analyzed for the content of sweeteners and preservatives. The sweeteners found in 28 samples was aspartame (0.17-11.59 g/kg) or saccharin (0.09-5.64 g/kg). Benzoic acid (0.02-1.72 g/kg) and sorbic acid (0.27-1.15 g/kg) were found as preservatives in 29 samples.

Acetonitriles↗
PubMed1997

Cytotoxicity of food preservatives in cultured rat hepatocytes loaded with linolenic acid.

We investigated the ability of eight food preservatives to induce lipid peroxidation in normal and alpha-linolenic acid (LNA)-loaded cultured rat hepatocytes. On the addition of sodium dehydroacetate (DHA-Na), potassium sorbate (SA-K) or thiabendazole (TBZ) to the cell culture, lipid peroxidation, assessed in terms of the production of malondialdehyde (MDA), was induced in LNA-loaded cells, but not in normal cells. At the low concentrations, induction of lipid peroxidation in LNA-loaded cells was highest with TBZ, whereas at high concentrations DHA-Na greatly induced lipid peroxidation. The occurrence of lipid peroxidation in LNA-loaded cells was accompanied by a decrease in cellular GSH levels with the three preservatives and by a decrease in cellular protein-SH levels with DHA-Na and TBZ. Furthermore, cell injury, measured by the release of LDH, was produced in LNA-loaded cells exposed to DHA-Na and SA-K. The addition of TBZ caused substantial cell injury in normal cells, and even greater injury in LNA-loaded cells. The prevention of lipid peroxidation in LNA-loaded hepatocytes by addition of an antioxidant, N,N'-diphenyl-p-phenylenediamine (DPPD) almost completely prevented DHA-Na- and SA-K-induced cell injury, and reduced TBZ-induced cell injury. The addition of diphenyl (DP), o-phenylphenol (OPP) or butyl p-hydroxybenzoate (BHB) caused severe cell injury, in association with a marked decrease in cellular levels of both of GSH and protein-SH in both groups of cells. However, lipid peroxidation was not detectable in either group of cells exposed to these preservatives. Sodium propionate (PA-Na) and sodium benzoate (BA-Na) had little effect on any cytotoxic parameter in either group of cells.

Animals↗