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PubMed2004

Estimation of trace amounts of chromium(III) in multi-vitamin with multi-mineral formulations.

Two new specific, selective, simple and inexpensive spectroscopic methods for estimating a trace amount of chromium (Cr3+) from a multi-vitamin with multi-mineral pharmaceutical formulations were developed. The proposed methods are based on the conversion of Cr3+ to Cr6+ either by oxidation with a nitric acid-perchloric acid mixture (method I) or by fusion with an excess amount of sodium carbonate (method II), followed by the complexation of Cr6+ with 1,5-diphenylcarbazide (DPC) in a mineral acidic solution of pH 1.0 +/- 0.5. The pink-colored complex was estimated at 544 nm. Both methods were found to be linear in the range of 0.1 - 0.8 microg/ml with a limit of detection in the range of 0.0123 - 0.0157 microg/ml and a limit of quantitation in the range of 0.0419 - 0.0525 microg/ml. Method I was found to be suitable for estimating Cr3+ species in various formulations, like tablets, capsules and syrups, while method II was found to be suitable for tablets and capsules. Satisfactory recovery from spiked samples of standard Cr3+ suggests no interference of any excipients and diverse ions present in the formulations. The developed methods were compared with AAS by ANOVA, and no significant difference was observed.

Calibration↗
PubMed1990

[A method of atomic absorption spectrophotometry (AAS) for analysis of cadmium and lead levels in the plant material].

The conditions were evolved and checked for simultaneous determination of cadmium and lead levels in plant material using the flame technique of ASA. For decomposition of the organic substances in plant material wet mineralization was used with a mixture of nitric acid, perchloric acid and sulpuric acid in volume proportions 6:2:0.25. The levels of cadmium and lead were determined in the organic phase after extraction with n-butyl acetate of the previously produced complexes with NaDDTK. The obtained limits of cadmium and lead detectability were 0.002 and 0.02 mg/kg respectively. The recovery rate of the method ranged from 96 to 98%, while the variability index was from 2.6 to 10.2%. The correctness of the evolved analytical procedure was confirmed by determination of the content of both elements in the NBS-SRM 1571 standard (orchard leaves) and by participation in the international interlaboratory investigation of the Polish standard (dried cabbage leaves).

Cadmium↗
PubMed1990

[Modified microdiffusion method for fluoride analysis of foodstuffs].

In fluoride analysis, there are two procedures for the determination of fluoride depending on nature of samples. One procedure directly can determine fluoride contents by fluoride ion electrode, dissociating fluoride from the sample with the acid (perchloric acid). The other procedure needs to separate fluoride from biological sample using steam-distillation or micro-diffusion method, and then the determination by means of fluoride ion electrode can be applied. In this study, we applied a modified microdiffusion method by Hinoide (1990) for its availability in different temperatures and reaction time, and then estimated to determine fluoride contents of Shrimp (Sakura-shrimp) as a biological sample by this method. It is also very important to determine fluoride contents of foodstuffs and biological samples with regard to bioavailability of fluoride in vivo. The results were as follows: 1. Using the modified microdiffusion method, the fluoride recovery rate attained more than 95% in the range of 0.1-10 micrograms fluoride from a standard solution under the experimental condition of 60 degrees C and 90 degrees C of reaction temperatures and 60, 90 and 120 minutes of reaction time. 2. For the sample of shrimp, fluoride contents analyzed by means of the modified micro-diffusion and steam-distillation methods showed almost similar values, although the fluoride contents by steam-distillation method revealed relatively lower value. The difference might be derived from a loss of fluoride in ashing the sample before applying the steam-distillation method. The modified microdiffusion method used in this experiment can be utilized routinely and precisely in fluoride analysis for small amounts of biological sample.

Animals↗
PubMed1989

[Determination of protein concentration in human saliva].

Seven colorimetric methods (Biuret, Lowry, a modified Lowry technique using bicinchoninic acid, Coomassie brilliant blue G (CBBG) dye-binding in phosphoric acid, perchloric acid or hydrochloric acid, and bromophenol blue dye-binding) were evaluated for determination of protein concentration in human whole saliva. Using bovine serum albumin (BSA), mucin, and thyroglobulin as protein standards to calculate salivary protein concentration gave different results among the assays used and even with the different standards of the same method. Among the seven methods used, the CBBG dye-binding assay in hydrochloric acid appeared to provide the most accurate estimation of protein concentration in human saliva. Using BSA as a standard, the mean values of human salivary proteins from 39 healthy individuals ranged from 0.72 to 2.45 mg/ml. The optimum conditions for the CBBG dye-binding assay in hydrochloric acid are: (1) the absorbance at 595 nm was measured between 15 to 30 minutes after addition of reagent. (2) the optimum concentration of dye in hydrochloric acid was 0.06-0.12% (w/v) for the assay. (3) the dye reagent was stable within one month.

Colorimetry↗
PubMedDate not supplied

Determination of selenium in urine by hydride generation atomic absorption spectrometry.

A procedure has been developed for determination of total selenium in urine by hydride generation atomic absorption spectrometry. Mineralization was performed with a nitric acid-perchloric acid mixture on a thermostated digestion block. The method was validated by comparison with the method involving mineralization in a microwave acid digestion bomb containing nitric acid and small amounts of vanadium pentoxide. Se(VI) was reduced to Se(IV) by dissolution in 7N HCl. Sample recoveries, precision studies, and analyses of a certified reference material demonstrated the reliability and accuracy of this technique. Urine samples had selenium concentrations ranging from 4.6 to 50.3 micrograms/L. These values correspond to an average of 54.9 micrograms per person per day total ingested and bioavailable Se in the daily diet.

Female↗
PubMed1996

Enzymatic method to determine dehydroascorbic acid in biological samples and in bread dough at various stages of mixing.

An enzymatic method is described for measuring L-dehydroascorbic acid in perchloric acid extracts of biological samples. The enzyme used in the assay was glutathione dehydrogenase (glutathione:dehydroascorbate oxidoreductase), which was purified from wheat flour using three column chromatography steps. The enzyme catalyzes the reduction of dehydroascorbic acid by glutathione, and the ascorbic acid product is measured spectrophotometrically at 265 nm. The assay is a fast (about 2 min) and simple two-step procedure. First, a mixture of extract and buffer is set to zero absorbance against air in a spectrophotometer. Second, a solution of glutathione dehydrogenase and glutathione is added and the absorbance after 2 min is used in a formula to calculate nmol dehydroascorbic acid/g or ml sample [513.8(Abs-0.013) x factor for dilution of extract]. The formula was derived from a calibration graph using pure L-dehydroascorbic acid standards. Pure L-dehydroascorbic acid was prepared from pure L-ascorbic acid, and the ascorbate oxidase used to catalyze the reaction was removed by ultrafiltration. Commercial L-dehydroascorbic acid (Aldrich) was unsuitable for use as a standard because the purity was only 56-67% in comparison to laboratory-prepared L-dehydroascorbic acid. The sensitivity of the assay was such that when dehydroascorbic acid was added to healthy human blood plasma during extraction with perchloric acid at the level of 7.5 nmol/ml plasma the dehydroascorbic acid could be measured with complete recovery. Low levels of dehydroascorbic acid were detected in fresh fruits and vegetables. When samples were ground for several minutes before extraction with perchloric acid, the dehydroascorbic acid levels increased more than 10-fold. Dehydroascorbic acid increased rapidly during mixing of bread dough containing added L-ascorbic acid.

Ascorbic Acid↗
PubMedDate not supplied

Determination of germanium in human specimens: comparative study of atomic absorption spectrometry and microwave-induced plasma mass spectrometry.

The determination methods of germanium (Ge) in biological specimens such as blood plasma, erythrocytes, urine, hair, nail, and other organs were established using graphite furnace atomic absorption spectrometry (GFAAS) and microwave-induced plasma mass spectrometry (MIP-MS). The detection limits of Ge standard solution were 3 ng/mL with GFAAS and 0.05 ng/mL with MIP-MS. The detection limits in organ samples depended on the type of samples and sampling amounts: 3-30 ng/g by GFAAS and 0.05-0.5 ng/g by MIP-MS. The sensitivity of GFAAS was lower than that of MIP-MS; however, it was adequate for determining Ge concentrations in specimens from patients who had ingested Ge. Samples were digested by a simple wet-ashing procedure using nitric acid and perchloric acid. To avoid the interfering effects of coexisting elements and perchloric acid residue, an extraction method using organic solvent was tried. When using MIP-MS, extraction was not necessary; however, both dilution and addition of an internal standard were needed. Special attention was required for iron-rich samples because a molecular ion of 56Fe16O was observed at nm/z72 where 2Ge was monitored. The results of Ge concentrations in human samples obtained by these methods agreed well. Interfering effects of perchloric acid, which was used for digestion and which remained in samples, were observed in both methods. Hair and nail samples from people who had ingested Ge were useful for monitoring Ge in the body. Hair samples were useful for determining past exposure to Ge when the distribution patterns from the scalp to the end of the strand were analyzed. In control subjects, Ge concentrations in the listed specimens and organs were lower than 0.1 microg/g or mL, and these low levels of Ge were able to be determined by MIP-MS in combination with the extraction method.

Aged↗
PubMed2002

Tentacle-type zwitterionic stationary phase prepared by surface-initiated graft polymerization of 3-[N,N-dimethyl-N-(methacryloyloxyethyl)-ammonium] propanesulfonate through peroxide groups tethered on porous silica.

A novel stationary phase with tentacle-type zwitterionic interaction layer was synthesized by free radical graft polymerization of 3-[N,N-dimethyl-N-(methacryloyloxyethyl)ammonium]propanesulfonate (SPE) from the surface of Kromasil porous silica particles. The polymerization was initiated by thermal cleavage of tert-butylperoxy groups covalently attached to the particle surface, and the material therefore carries a tentacle-type polymeric interaction layer with 3-sulfopropylbetaine functional moieties. The composition of the surface graft was determined by elemental analysis, and the surface charge was measured using photon correlation spectroscopy. The measured zeta-potentials were close to 0 and nearly independent of pH, and the tentacle character of the interactive layers were evident from the lack of colloidal stability in the absence of salt (antipolyelectrolytic behavior) and a marked increase in column back-pressure when the concentration of perchloric acid or perchlorate salt was increased. The chromatographic properties were evaluated on columns packed with the functionalized material, and it was shown that this zwitterionic stationary phase could simultaneously and independently separate inorganic anions and cations using aqueous solutions of perchloric acid or perchlorate salts as eluents. The material was also capable of separating two acidic and three basic proteins in a single run, using gradient salt elution at constant pH.

Journal Article↗
PubMed1996

Differential reactivities of the mono- and di-epoxide of 1,3-butadiene.

The acid-catalysed (perchloric acid) hydrolysis of 1,2-epoxybutene-3 (EB) and of 1,2:3,4-diepoxybutane (DEB), two reactive epoxide metabolites of 1,3-butadiene (BD), was determined based on reaction of unchanged epoxide with 1-nitro-4-pyridyl-benzene (NBP). Related to different epoxide concentrations, both reactions were of first order. Related to different proton concentrations, second-order rate constants were obtained (approximately 10 s-1 M-1 perchloric acid for EB; approximately 0.01 s-1 M-1 perchloric acid for DEB). These data show a much higher chemical stability of DEB compared to EB. Moreover, EB and DEB were reacted at pH 7.2 in 10 mM TRIS buffer with deoxyguanosine (dG), guanosine (G) or calf thymus DNA. The unreacted epoxides (EB or DEB) present in the incubation mixtures with time were determined by gas chromatography. Consistent with the results of the acid-catalysed hydrolysis, the second-order rate constants for reaction with dG, G or DNA were more than 10-fold higher with EB, compared to those with DEB.

Carcinogens↗
PubMed2002

Ergosteroids VII: perchloric acid-induced transformations of 7-oxygenated steroids and their bio-analytical applications--a liquid chromatographic-mass spectrometric study.

Sulfate esters of 7-oxo-delta(5)-steroids can be selectively and quantitatively hydrolyzed to the corresponding free steroids in the presence of carboxylic acid esters by solvolysis with perchloric acid in ethyl acetate at room temperature. Sulfates as well as carboxylic acid esters, methyl ethers, and ketals can be quantitatively converted to the corresponding 3,5-diene-7-one derivatives by heating with perchloric acid in methanol at 65 degrees C. The dienes have a strong UV absorption with maximum centered around 284 nm. These reactions have been used for the characterization and structural elucidation of 7-oxygenated-delta(5)-steroids that are present in complex biomatrices and can also be used for the quantitative estimation of total 7-oxo-delta(5)-steroids (free as well as conjugated) in biological matrices.

Animals↗
PubMed2005

Retention behavior of o-phthalic, 3-nitrophthalic, and 4-nitrophthalic acids in ion-suppression reversed-phase high performance liquid chromatography using acids instead of buffers as ion-suppressors.

In reversed-phase high performance liquid chromatography, the logarithm of the retention factor, log k, is usually correlated with the logarithm of the octanol-water partition coefficient, log Kow. The k and Kow of an ionizable analyte are greatly influenced by the mobile phase pH. In this paper, log kw of diprotic o-phthalic, 3-nitrophthalic, and 4-nitrophthalic acids, are obtained by extrapolation to pure aqueous fraction of mobile phase in ion-suppression reversed-phase high performance liquid chromatography with acetic acid and perchloric acid as the ion-suppressors. The Kow values of the three analytes are calibrated according to the apparent octanol-water partition coefficient, Kow, under different pH conditions, and the log K"ow values show a much better correlation with log kw than do log Kow. The influences of two ion-suppressors, acetic and perchloric acids, on the retention behavior of these diprotic acids at different pH are contrasted. An abnormal trend is found in the k vs. pHw plot of the acetic acid system when the methanol content is low. A possible reason is that acetic acid is an even stronger organic modifier than methanol, besides being an ion-suppressor. The results make the selection of mobile phase for the separation of acidic compounds by ion-suppression reversed-phase high performance liquid chromatography direct, accurate, and practical.

Acetic Acid↗
PubMed1983

Comparison of rat blood preparation methods for acetaldehyde assay.

A comparison is made of four previously described methods for the preparation of blood for acetaldehyde (AcH) assay in the rat. The spontaneous formation of AcH which occurs during the treatment of blood containing ethanol and the recovery of known amounts of AcH added to the blood were studied. The methods using sodium nitrite-sulfosalicylic acid or perchloric acid (PCA) in saline gave low levels of spontaneous formation (1 to 2 microM AcH for 48 mM ethanol). In the recovery studies it was seen that semicarbazide does not allow displacement of all the AcH; treatment of the blood with the reactant sodium nitrite-sulfosalycilic acid and use of the hemolysis method gave levels of recovery lower than 50%. Only treatment of the blood with perchloric acid in NaCl allowed all the AcH added to the blood to be recovered. In vivo, PCA in saline releases the AcH which was seen to remain bound in the red blood cells with the semicarbazide method. So the recommended procedure for accurate assay of blood AcH in the rat is cold deproteinization in PCA/saline before head-space gas chromatography. The levels of in vivo blood AcH (4.1 +/- 0.33 microM) obtained in the rat using this method for a blood alcohol concentration of 52 mM are lower than those previously described in the literature.

Acetaldehyde↗
PubMed2005

From solution phase to "on-column" chemistry: trichloroacetimidate-based glycosylation promoted by perchloric acid-silica.

[reaction: see text] Activation of ester-protected glycosyl trichloroacetimidate donors by perchloric acid immobilized on silica afforded 1,2-trans disaccharides in 60-90% yields. Applying this approach to one-pot sequential glycosylation resulted in efficient syntheses of the N-linked glycan trimannoside and Le(X) and Le(A) trisaccharides in very good yield (76%, 62%, and 59% yields, respectively). Solution phase reactions were also translated to a solid phase format; priming the top of a standard silica chromatography column with perchloric acid immobilized on silica facilitated "on-column" glycosylation with subsequent "in situ" purification of products. Coupling yields from this approach were comparable to those obtained from the corresponding solution-phase disaccharide couplings. A series of glycosylated amino acids were also synthesized in high yield with use of the on-column approach.

Acetamides↗
PubMed1995

Isolation and characterization of a novel perchloric acid-soluble protein inhibiting cell-free protein synthesis.

We found a novel protein in the postmitochondria supernatant fraction of rat liver, which is soluble in 5% perchloric acid and strongly inhibits protein synthesis in a rabbit reticulocyte lysate system. The protein extracted from the supernatant fraction with 5% perchloric acid was purified by ammonium sulfate fractionation and CM-Sephadex chromatography. The protein was shown to consist of two identical subunits with a molecular mass of 14 kDa. By immunoscreening with the rabbit antisera against the protein, a cDNA encoding the protein was cloned and sequenced. The cDNA contained an open reading frame of 411 base pairs encoding a 136-amino acid protein with a molecular mass of 14,149 Da. The deduced amino acid sequence was completely identical with that constructed from all of the above peptides. Interestingly, the perchloric acid-soluble protein inhibited cell-free protein synthesis in the rabbit reticulocyte lysate system in a different manner from RNase A. The protein is likely to inhibit an initiation stage of cell-free protein synthesis. Among the rat tissues tested, the protein was located only in liver and kidney. These findings are the first report on a new inhibitor that may be involved in the regulation of protein synthesis in those tissues.

Amino Acid Sequence↗
PubMed1970

A method for the estimation of the catecholamines and their metabolites in brain tissue.

1. A method is described whereby the catecholamines, their precursors and metabolites may be estimated in the same brain sample. The method, outlined below, was rigorously tested in pure solution before being applied to the estimation of the catechol and methoxyamines in extracts of rat brain. (i) The brain tissue was homogenized in perchloric acid and the perchloric acid removed as its insoluble potassium salt. (ii) The acid metabolites of the amines were extracted from the acidified extract into ethyl acetate. (iii) After extraction with ethyl acetate, the aqueous extract was treated with acetic anhydride and sodium hydrogen carbonate and the acetylated derivatives of the amines extracted into dichloromethane. (iv) The aqueous solution remaining after extraction with dichloromethane contains the acetylated amino-acids. Acetyl-dopa could be extracted into dichloromethane only after acidification of this aqueous solution. The acetyl-dopa in this dichloromethane extract could be estimated fluorimetrically. (v) The dichloromethane extract containing the acetylated amines was chromatographed on paper in the organic phase of a mixture of toluene:ethyl acetate:methanol:water, 10:1:5:5. (vi) The acetylated amines were eluted and estimated fluorimetrically. A new method was developed for the estimation of 3-methoxytyramine and its acetylated derivative.2. The reproducibility of the method was demonstrated by the consistent estimates obtained for the concentrations of noradrenaline, dopamine and 3-methoxytyramine in whole rat brain. Adrenaline and metanephrine were not detected. The concentration of normetanephrine in rat brain was at the limit of detection of the method.3. Although the estimation for the levels of endogenous amines in whole rat brain were consistent, the recoveries of exogenous amines taken through the procedure were low and very variable. Control experiments demonstrated that the exogenous amines were lost at the perchloric acid extraction stage of the procedure.

Animals↗
PubMed1982

Perchloric acid-soluble serum glycoprotein as an index for tumor cell burden in the early detection of cancer.

Neoplastic cells, particularly human mammary carcinoma cells, shed or secrete glycoproteins which are tumor-specific. These compounds contain N-acetylneuraminic acid (NANA) and they differ from the bulk of serum proteins and glycoproteins in being soluble in perchloric acid. Graded number of R3230 adenocarcinoma (AdCa) cells were implanted subcutaneously in groups of female Fisher rats. At time intervals, while under anesthesia the spleens were dissected out, and blood was drawn from the animals. The blood was examined for NANA levels and the spleen cells for lymphocyte migration inhibition. The serum perchloric acid (PA) soluble proteins and the PA-NANA levels were time-dependent and increased with the number of implanted tumor cells. Maximum levels were found in sera from blood drawn 196 hours or later from animals which received 1,000 tumor cells/rat, or more. At 72 hours or more after tumor cell implantation, migration of splenic lymphocytes from animals which received 100 or more R3230 AdCa cells per animal was inhibited on contact with neuraminidase-treated formalinized R3230 AdCa cells. The magnitude of inhibition increased with time and with the number of implanted tumor cells. Therefore, blood PA-NANA levels and lymphocyte migration inhibition rae parameters for the in-vivo early detection and monitor tumor cell proliferation.

Adenocarcinoma↗
PubMed2005

[Simultaneous determination of germanium and some major ash forming elements in lignites using a dual-view ICP-OES].

In this article, an ICP-OES method of simultaneous determination germanium and some major ash forming elements especially for Fe, Al, Ca, Mg, K, Na, Ti in lignites is described. An ICP-OES instrument equipped with a dual-view plasma torch and a simultaneous detector was used. This technology allows the simultaneous determination of trace elements and major components in the axial view along with in the radial view. The moderate operation condition of the instrument and analytical wavelength lack of interference from elements in the sample matrix was selected, the spectral background was automaticly eliminated. The obtained coal ashes were dissolved in mixtures of nitric acid, hydrofluoric acid and perchloric acid after coal samples were cinerated. The analytical results were in good agreement with those provided by national standard methods. The detection limit of the instrument is ranged between 0.00039-0.10 microg. x mL(-1), the precision of the method is in the range of 0.79%-2.84%, the average recovery of samples is 92.38%, the proposed method is well suitable for the determination germanium and some major ash forming elements in lignites.

Aluminum↗