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PubMedDate not supplied

Solid phase extraction and spectrophotometric determination of trace amounts of thiocyanate in real samples.

A simple, selective and rapid method for solid phase extraction and spectrophotometric determination of thiocyanate using a manganese (III) tetrakis (p-sulfonatophenyl) porphyrin, [Mn (TPPS) OAC] bound to Amberlite IR-400 has been developed. The influence of pH, amount of solid phase, sample matrix, type and amount of eluting agent and flow rates i.e. variables affecting the efficiency of the extraction system were evaluated and conditions of the sample, eluting solution and active phase were optimized. The maximal capacity was found to be as 1.16 microg mL(-1) for 1200 mL. Thiocyanate ions can be eluted quantitatively with 8 mL 0.3 M ferric chloride. The enrichment factor was 150. The linear range of the determination is between 0.4-2.0 microg mL(-1) for preconcentration method with a limit of detection of 2.8 ng mL(-1). The method has been successfully applied for determination of trace amounts of thiocyanate in tap water, saliva sample and a synthetic mixture.

Humans↗
PubMed1992

Modifiers of mercaptopyruvate sulfurtransferase catalyzed conversion of cyanide to thiocyanate in vitro.

The enzyme mercaptopyruvate sulfurtransferase appears to play an important role in the in vivo detoxification of cyanide. It does so by transferring sulfur to cyanide to produce thiocyanate, which is less toxic and may be excreted through the kidney. Several compounds were tested for their ability to affect the rate of enzyme catalyzed thiocyanate formation in vitro. The studies were carried out using both a partially purified bovine kidney extract and a highly purified enzyme preparation. Hypotaurine and methanesulfinic acid doubled sulfurtransferase activity in the partially purified extract at 30 mM, but inhibited the purified enzyme to 57% (hypotaurine) and 27% (methanesulfinic acid) of control activity at the same concentration. Pyruvate, phenylpyruvate, oxobutyrate, and oxoglutarate each inhibited the extract and purified forms of mercaptopyruvate sulfurtransferase. Phenylpyruvate was the most effective inhibitor, reducing activity to 0.2% of control values in the extract, and 11% of control values for purified MPST when added to the reaction at 30 mM. Other compounds tested (see Table 1) had a negligible effect on sulfurtransferase activity. A heat stable cofactor was found in boiled kidney extract which stimulated sulfurtransferase activity in the extract but inhibited sulfurtransferase activity in the purified enzyme, as was observed for hypotaurine and methanesulfinate. The boiled extract had no thiocyanate forming activity of its own. The cofactor operated in synergy with methanesulfinate, but independently of hypotaurine.

Catalysis↗
PubMed2001

Dietary supplies of iodine and thiocyanate in the etiology of endemic goiter in Tripura.

In the post-salt iodization phase, a study on iodine nutriture status was conducted in Tripura of North East India. The clinical variable of the study was goiter and the biochemical variables were urinary iodine and thiocyanate. Random sampling methodology was followed for selecting the study areas in the State. In each study area, the studied population consisted of school children of both sexes in the age group 6-15 years. The total study areas were 22 and the total number of the population was 10,801. The total number of urine samples were analysed for iodine and thiocyanate were 1,032 (about 10%). The total goiter rate was 21.63%. Population of most of the studied areas had no biochemical iodine deficiency as evidenced by median urinary iodine excretion levels. However, the per capita consumption of iodine of about 40% population was inadequate. A large number of cyanogenic plants (SCN precursors) are used as common vegetables. This study ensures that the existing goiter prevalence in the region could possibly due to non-uniform adequate iodine supply along with the thiocyanate load.

Child↗
PubMed1978

Influence of thiocyanate ions on starch-iodine reaction used for the estimation of alpha-amylase activity.

A strong simulating effect of thiocyanate ions during the estimation of alpha-amylase by the amyloclastic method is shown. Thiocyanate ions themselves catalyse the decolorization of the starch-iodine complex. This may lead to wrong values during determination of alpha-amylase by this method. The rate of thiocyanate-iodine reaction depends upon the hydrogen ion concentration of the iodine reagent.

Amylases↗
PubMed1986

Formation of HCN and its chlorination to ClCN by stimulated human neutrophils--2. Oxidation of thiocyanate as a source of HCN.

Leucocytes challenged by Staphylococcus epidermidis or stimulated by phorbol myristate acetate (PMA) produce cyanide from thiocyanate. The amount of H14CN formed depends on KS14CN concentration and is enhanced by pretreatment of phagocytosed bacteria with penicillin or by adding amine-taurine to the medium of PMA-stimulated neutrophils. The reaction of taurine chloramine or chlorinated Staphylococcus epidermidis (containing N-Cl groups) with thiocyanate results in HCN formation. At higher concentration of chloramine cyanogen chloride is formed. Cyanide is chlorinated by PMA-stimulated neutrophils and this process is significantly enhanced by exogenous taurine and inhibited by 3-amino 1,2,4-triazole. It is conceivable that oxidation of thiocyanate to HCN and chlorination of HCN to ClCN is mediated by the chlorinating species (taurine chloramine) produced by stimulated neutrophils.

Carbon Radioisotopes↗
PubMed1991

Serum thiocyanate levels in a normal population and in pregnancy in Benin City, Nigeria: preliminary report.

Sera from pregnant and nonpregnant women were analyzed for thiocyanate. Serum thiocyanate concentration was higher in Nigerians compared with Caucasians and was significantly higher also in pregnancy. Hypoalbuminemia and dietary consumption of cyanogenic substances in pregnancy probably contributed to the higher thiocyanate levels. This may have a possible significant bearing on the fetal well-being, particularly fetal birthweight.

Adult↗
PubMed1996

Evidence for more extensive deposits of epitopes of oxidized low density lipoprotein in aortas of young people with elevated serum thiocyanate levels. PDAY Research Group.

Elevated levels of low density lipoprotein (LDL) and smoking have long been recognized as risk factors for atherosclerosis and coronary heart disease (CHD). However, the mechanisms by which these factors contribute to the disease have not been fully elucidated. It has been postulated from in vitro studies using serum and LDL from smokers that smoking increases the oxidation of LDL, which in turn contributes to atherogenesis. We know of no direct evidence linking oxidized LDL (oxLDL) in human arteries to increased atherosclerosis in individuals who show elevated serum thiocyanate levels (HST) as an indicator of recent smoking. We have studied arterial samples from smokers micromorphometrically and found that 'smokers' have a greater area in which oxLDL can be identified in the early stages of the disease than do "nonsmokers', i.e., individuals with low serum thiocyanate levels (LST). This study demonstrates a positive correlation between the extent of oxLDL in the fatty streaks as well as the fatty plaques of standardized core sample areas of the thoracic and abdominal aortas of a sample group of young people, aged 15-34, who have evidence of recent smoking based on their postmortem serum thiocyanate levels.

Adolescent↗
PubMed1983

Cigarette smoking: carboxyhemoglobin, plasma nicotine, cotinine and thiocyanate vs self-reported smoking data and cardiovascular disease.

Measurement of the absorption of cigarette smoke constituents were compared with self-reported daily consumption from 450 smokers to determine the most reliable dose dependent indicator of smoke inhalation and risk for coronary heart disease. A plateau of plasma nicotine and cotinine concentration at levels above 20 cigarettes per day with a continued increase of carboxyhemoglobin and thiocyanate with increasing consumption of cigarettes occurred. Classification of smokers into groups smoking cigarettes yielding more or less than 1 mg nicotine showed that smokers of low yield brands had lower plasma levels of nicotine and cotinine, but comparable levels of carboxyhemoglobin and thiocyanate. Plasma nicotine bore no relationship to smoke inhalation, while the number of cigarettes consumed per day showed a weak correlation to smoke inhalation. Despite the lower nicotine yield of cigarettes, modification in smoking behaviour enabled the smoker to derive as much carbon monoxide and thiocyanate constituents from low and high yield cigarettes; thus counteracting the advantage of low nicotine yield brands. The relationship of these parameters to the risk of coronary heart disease is discussed.

Carbon Monoxide↗
PubMed1986

Antibody avidity determination by ELISA using thiocyanate elution.

Antibody avidity of human anti-rubella antibodies has been determined using the chaotropic thiocyanate ion in ELISA assays. Independence of antibody level and affinity was shown and the pattern of post-vaccination antibody affinity established. A variation of the standard ELISA assay was developed where replicate wells containing antibody bound to antigens were exposed to increasing concentrations of the chaotropic thiocyanate ion. Resistance to thiocyanate elution was utilised as the measure of avidity and an index (affinity index) representing 50% of effective antibody binding was used to compare different sera. The interplate coefficient of variation for the affinity index was 12.6% whereas the intraplate coefficient of variation was 4.1%.

Antibodies, Viral↗
PubMed1986

Verification of smoking status by thiocyanate in unrefrigerated, mailed saliva samples.

A simple method of obtaining an unbiased verification of smoking status was developed for use in a randomized clinical trial. At the end of smoking cessation intervention for pregnant women, each participant mailed a saliva sample to a laboratory for the determination of thiocyanate. For comparison, salivary thiocyanate also was measured by a standard collection method in a reference group of non-study women who did not smoke during pregnancy. Although there may have been up to a 1-week delay between collection and analysis, results show that thiocyanate from unrefrigerated, mailed samples of saliva distinguishes reported smokers from nonsmokers, is positively associated with the amount of smoking, and is negatively associated with the length of cessation. These study findings are consistent with results from other studies in which samples of serum or saliva were collected and shipped under conditions requiring the presence of a staff member. The ability to perform an unbiased smoking status verification using a simple, inexpensive, and noninvasive collection method expands study possibilities, as it eliminates the need for direct, face-to-face contact with study subjects, and for being at their location.

Adolescent↗
PubMed1992

Formation of proline thiohydantoin with ammonium thiocyanate: progress towards a viable C-terminal amino-acid-sequencing procedure.

Pure amino acid thiohydantoins are required as reference standards for development of C-terminal-sequencing procedures based on thiohydantoin formation of the C-terminal amino acids of peptides and proteins. Proline thiohydantoin was prepared using a straightforward method involving reaction of acetylproline with ammonium thiocyanate. It was characterized by UV spectrophotometry, mass spectrometry and back-hydrolysis to the free amino acid. These data establish unequivocally that the thiocyanate procedure is applicable to proline as well as to the other common amino acids. This work also validates earlier claims that proline thiohydantoin can be prepared by reaction with thiocyanic acid.

Amino Acid Sequence↗
PubMed1994

A fluorometric assay of peroxidase activity utilizing 2',7'-dichlorofluorescein with thiocyanate: application to the study of salivary secretion.

A sensitive assay for secretory peroxidase activity has been developed utilizing the fluorogenic substrate 2',7'-dichlorofluorescin in the presence of thiocyanate. The assay has been characterized using bovine lactoperoxidase and used to determine the peroxidase activities of salivas and extracts obtained from rat submandibular glands. Comparison of the 2',7'-dichlorofluorescin-thiocyanate assay and the commonly used 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonic acid) colorimetric assay indicates that the new assay is approx. 50-fold more sensitive. This has enabled measurement of peroxidase activities present in parasympathetic saliva samples which were beyond the detection limit of the colorimetric assay. Despite great differences in the peroxidase activities and protein concentrations of parasympathetic and sympathetic salivas and tissue extracts, the activities per unit protein were very similar. Unlike most other published methods, prior dialysis of samples to remove interference by endogenous thiocyanate is not required. The assay is therefore convenient and will be particularly useful for applications in which sample volume or peroxidase activity is low.

Animals↗
PubMed1994

A fluorometric assay of peroxidase activity utilizing 2',7'-dichlorofluorescein with thiocyanate: application to the study of salivary secretion.

A sensitive assay for secretory peroxidase activity has been developed utilizing the fluorogenic substrate 2',7'-dichlorofluorescein in the presence of thiocyanate. The assay has been characterized using bovine lactoperoxidase and used to determine the peroxidase activities of salivas and extracts obtained from rat submandibular glands. Comparison of the 2',7'-dichlorofluorescein-thiocyanate assay and the commonly used 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) colorimetric assay indicates that the new assay is approx. 50-fold more sensitive. This has enabled measurement of peroxidase activities present in parasympathetic saliva samples which were beyond the detection limit of the colorimetric assay. Despite great differences in the peroxidase activities and protein concentrations of parasympathetic and sympathetic salivas and tissue extracts, the activities per unit protein were very similar. Unlike most other published methods, prior dialysis of samples to remove interference by endogenous thiocyanate is not required. The assay is therefore convenient and will be particularly useful for applications in which sample volume or peroxidase activity is low.

Animals↗
PubMed1982

Kinetics of hypothiocyanite production during peroxidase-catalyzed oxidation of thiocyanate.

We report here a kinetic study of the generation of hypothiocyanite (OSCN-), a product of lactoperoxidase-catalyzed oxidation of thiocyanate ion. Previous studies have measured OSCN- by reactions involving the oxidation of sulfhydryl compounds. Our results show that a more suitable kinetic analysis of OSCN- can be based on absorbance changes measured at 235 nm. About 90% of the oxidation products of SCN- observed at 235 nm were reactive with sulfhydryls and could be reduced with 2-mercaptoethanol. Both thiocyanate and peroxide were rate-limiting and the formation of OSCN- was proportional to the initial concentration of H2O2 until an equimolar concentration of H2O2 and SCN- was reached. This equimolar concentration gave the maximum generation of OSCN-. High concentrations (greater than 100 micrograms/ml) of lactoperoxidase decreased OSCN- generation, but only if the SCN- was added to the enzyme prior to addition of H2O2. With lactoperoxidase concentrations exceeding 1 microgram/ml, the reaction velocity was rapid, but the decay of OSCN- was slow. Free H2O2 in the reaction mixture always resulted in rapid decay of OSCN-. Addition of varying concentrations of peroxide to solutions containing 1 microgram/ml of enzyme and [SCN-] = 5 mM gave a family of hyperbolic A235 vs. time curves. Both the initial slopes and the plateaus of these curves increased linearly with increasing initial peroxide concentrations up to [H2O2] = 0.4 mM, remained relatively constant in the range [H2O2] = 0.4 to 0.8 mM, and decreased rapidly above [H2O2] = 0.8 mM. These results are consistent with the following kinetic model: Hydrogen peroxide reacts rapidly with lactoperoxidase to produce compound I. This compound I oxidizes SCN- to OSCN- and also oxidizes OSCN- to O2SCN-. The OSCN- also reacts with SCN-. The formation of OSCN- is associated with the appearance of an absorbance peak at 225-235 nm. The oxidation of OSCN- by excess peroxide or its decomposition at high concentrations is associated with a decrease in A235 and the appearance of a peak at 245-255 nm. The extinction coefficient for OSCN- was determined to be 1.29 x 10(3) M-1 . cm-1. The second-order rate constant for the oxidation of thiocyanate by compound I was estimated to be 2 x 10(5) M-1 . s-1.

Kinetics↗
PubMed1985

Reducing the confounding effects of environment and diet on saliva thiocyanate values in ex-smokers.

This study focuses on the use of saliva thiocyanate to corroborate self-report in 391 adult ex-smokers who claimed abstinence from cigarettes for a minimum of 3 months. Results indicated significant thiocyanate confounders, such as using and inhaling nontobacco organic substances, working in a "smoky" environment (i.e., tobacco smoke), and consuming varieties of Brassica oleracea (e.g., cabbage), that could be identified and adjusted for in order to clarify classification of smoking status. Before adjustment for confounders, 18% of subjects reporting abstinence had saliva thiocyanate values greater than the standard cut-off point of 100 micrograms/ml, which would classify them as current smokers. After adjustment, only 12% of subjects still had values greater than 100 micrograms/ml.

Adult↗
PubMed1986

The saliva thiocyanate analysis: a methodological extension and its relationship to CO and self-report in moderate smokers.

Parameters for the storage and analysis of saliva samples used to measure thiocyanate (SCN) levels among moderate smokers were systematically studied. The variables targeted for study were the temperature of storage (0 to 20 degrees F) and the size of the container (5 ml or 10 ml). Additionally, these same variables were examined, independently under three different temporal delays to laboratory analysis: immediate, 3 days, and 7 days. Results within each of the delay conditions revealed no significant differences in SCN levels and provided support for the reliability of measurement when using these procedures in the study of thiocyanate levels. Self-reported smoking rate and alveolar carbon monoxide (COa) readings of a week prior were found to correlate relatively highly with thiocyanate readings. These findings broaden the support for SCN as a corroborative measure of smoking.

Carbon Monoxide↗
PubMed1996

Determination of cyanide and thiocyanate in blood by gas chromatography and gas chromatography-mass spectrometry.

We devised a sensitive and simple method for determining cyanide and its major metabolite, thiocyanate, in blood using an extractive alkylation technique. Pentafluorobenzyl bromide was used as the alkylating agent, and tetradecyldimethylbenzylammonium chloride was used as the phase-transfer catalyst. The derivatives obtained were analyzed qualitatively by gas chromatography-mass spectrometry and quantitatively by gas chromatography with an electron-capture detection. The detection limits of cyanide and thiocyanate were 0.01 and 0.003 mumol/ml, respectively, while the gross recovery of both compounds was 80%. The calibration curve was linear over the concentration range from 0.02 to 1.0 mumol/ml for cyanide and from 0.01 to 1.0 mumol/ml for thiocyanate. The accuracy and precision of the method were evaluated, and the coefficients of variation were found to be within 10%. Using the method, the blood levels of two victims who had died from cyanide poisoning were determined.

Chromatography, Gas↗
PubMed1996

The reevaluation of the ferric thiocyanate assay for lipid hydroperoxides with special considerations of the mechanistic aspects of the response.

The mechanistic aspects of the spectrophotometric method of analysis of lipid hydroperoxides (LOOH) based on the oxidation of ferrous to ferric ion and subsequent complexation of the latter by thiocyanate are considered. The method of analysis, as revised by us, was carried out in the same solvent that had been used for the extraction of lipids from the sample, a deoxygenated chloroform:methanol or a dichloromethane:methanol (2:1, v/v) mixture, and used a single solution containing both reagents, Fe2+ and SCN-, for developing the response. In that solvent, total lipids up to 5 mg/ml did not interfere, and linear increase of the absorbance of ferric thiocyanate complex was obtained up to 2 x 10(-5) M LOOH. Molar absorptivity of the ferric thiocyanate complex expressed per mol of LOOH was determined as 58,440 M-1 cm-1, based on the average of four ferric ions produced by each LOOH molecule. The estimated lowest detectable limit was about 170 pmol LOOH/ml of analyzed solution, which corresponded to about 50 mumol LOOH/kg lipid in complex natural mixtures. In addition to good sensitivity, and in contrast to some other more popular spectrophotometric assays for LOOH, the method is responsive also to hydroperoxides of mono- and di-unsaturated fatty acids. The method, thus, provides an easy, rapid, sensitive, and complete measure of hydroperoxidation of lipids.

Cobalt Radioisotopes↗