Analysis of organic and inorganic selenium anions by ion chromatography-inductively coupled plasma atomic emission spectroscopy

We report analysis of both inorganic and amino acid forms of selenium by ion chromatography with inductively coupled plasma atomic emission spectroscopic detection. Three chromatographic systems are compared; effects of representative sample matrices on the separations are investigated. We are unable to resolve selenate and seleno-cystine using the Dionex AS4A column. Elution of seleno-cystine and seleno-cysteine is strongly suppressed in samples of bacterial cell extract matrix analyzed with the Dionex AS10 column; this interference is not observed with the Dionex AS11 column. Synthetic sea water sample matrix has little effect on analytical results. Quantitation parameters are reported.

Serum selenium, copper, and zinc concentrations in Crohn's disease and ulcerative colitis

Serum selenium, copper, and zinc levels were studied in 47 patients with Crohn's disease, 117 patients with ulcerative colitis, and 123 age- and sex-matched healthy controls. Serum selenium levels were lower and serum copper levels were higher in men and women with Crohn's disease than in controls (p < 0.001 and p < 0.01, respectively). Trace element levels were not significantly influenced by extent or localization of Crohn's disease. Men and women with ulcerative colitis had higher levels of copper and zinc than did controls (p < 0.01 and p < 0.05, respectively). Men with pancolitis had significantly lower selenium and higher copper levels than men with proctitis. The implications of abnormal trace element status in patients with inflammatory bowel disease are discussed.

A comparative study of serum selenium and vitamin E levels in a population of male risk drinkers and abstainers. A population-based matched-pair study

Depressed selenium and Vitamin E levels may contribute to hepatic injury through lipid peroxidation. To study the effect of moderate alcohol drinking (32.4 +/- 23.6 g ethanol/d) on serum selenium and serum vitamin E concentrations, we conducted a matched-pair study of 73 healthy, well-nourished risk drinkers and healthy controls with little or no alcohol consumption. Among risk drinkers, serum selenium was significantly lowered (1.49 vs 1.67 mumol/L; p < 0.001) compared with controls. Difference in alpha-tocopherol concentrations did not, however, reach statistical significance (22.8 vs 24.9 mumol/L; p = 0.06). Nutritional and life-style factors differed very little between the two groups. We conclude that even moderate alcohol consumption lowers selenium status. Selenium may thus represent a link joining the hepatotoxic and nutritional backgrounds of alcoholic liver disease.

Determination of selenium in urine by isotope dilution gas chromatography-mass spectrometry using 4-nitro-o-phenylenediamine, 3,5-dibromo-o-phenylenediamine, and 4-trifluoromethyl-o-phenylenediamine as derivatizing reagents

An isotope dilution gas chromatography-mass spectrometry method for selenium determination in urine using 76Se as an internal standard is described. Three different derivatizing reagents, 4-nitro-o-phenylenediamine (NPD), 3,5-dibromo-o-phenylenediamine (DBPD), and 4-trifluoromethyl-o-phenylenediamine (TFMPD) were investigated for their gas chromatographic behavior including memory and precision and accuracy of isotope ratio measurements. By these criteria, the performance of these reagents was TFMPD greater than DBPD greater than NPD. Overall precision values of 1 to 7% were observed in determining Se isotope ratios at the 10-ng level, with no significant difference in using any of the three reagents. Memory effect was observed in the order NPD greater than DBPD greater than TFMPD with TFMPD showing no measurable memory effect. Accuracy of the GC-MS method was verified by quantitation of selenium in the NIST freeze-dried urine reference material SRM 2670.

Serum selenium level in patients with colorectal cancer

Serum selenium levels were determined by fluorometric procedure in 37 patients of both sexes suffering from colorectal cancer. The diagnosis was verified with histopathological examination during surgical treatment. The values found were 46.8 +/- 11.2 micrograms/L. The control group consisted of 230 healthy persons from the same environment as the group of patients. The values found were 64.2 +/- 11.5 micrograms/L. The results of this study are compared with the results of the other research groups analyzing the level of selenium in colorectal cancer.

Determination of selenium in blood components by X-ray emission spectrometry. Procedures, concentration levels, and health implications

Sampling, storing, sample pretreatment, and experimental conditions for selenium (Se) determination in human serum, plasma, and whole blood by X-ray emission spectrometric (XRS) methods are described. Concentration levels in these biological fluids, found by this technique, are discussed and compared to values found by other techniques for the same healthy population group in the same area. XRS analysis of blood from patients with various pathological conditions is reviewed, with special attention to the relation of Se with the concentration level of other essential or nonessential trace elements.

Selenium: clinical significance and analytical concepts

Selenium is an essential trace element in humans and animals. Its only established function in humans is the antioxidant activity of glutathione peroxidase, a selenoenzyme. Severe prolonged deficiency may cause a fatal cardiomyopathy. Iatrogenic causes of selenium deficiency include parenteral and enteral nutrition. Low plasma selenium is also found in malabsorption, cystic fibrosis, rheumatoid arthritis, neoplasia, and other varied clinical disorders. Death has resulted from a single massive ingestion of selenium, while chronic excessive intake causes skin, nail, and hair pathology. Extreme geographical variation in population blood and urine selenium levels and a marked age-specific variation in population reference intervals are important factors in understanding selenium nutrition. Nutritional requirements, biological availability, and metabolism are discussed in relation to geographical, age, and method variability. Sampling, processing procedures, and methods for selenium quantitation are reviewed. Selenium content in different biological matrices and reference values for pediatric, adult, and obstetric populations are provided.

Rapid and simple determination of selenium and other trace elements in very small blood samples by XRF

Selenium and other trace elements (Cu, Zn, Br, and Rb) were determined in very small (0.75 microL) human serum and mice whole blood samples, by an XRF method. Accurate results of elemental concentration were obtained without the need of exact volume measurement, because of the backscatter correction used. The XRF method is highly sensitive (M.D.L. = 0.06, 0.13, 0.09, 0.07, and 0.05 ppm for Se, Cu, Zn, Br, and Rb, respectively), rapid (counting time--100 s/sample), easy to perform and therefore suitable for routine trace element analyses. The results obtained are in good agreement with the values reported in the literature.

Serum selenium and risk of cancer. A prospective follow-up of nine years

The association between serum selenium concentration and the risk of cancer was studied in 1110 men aged 55 to 74 years in two rural areas of Finland. The men were followed-up prospectively for 9 years and there were 109 new cases of cancer, with the cases of the first follow-up year excluded. The serum selenium concentrations were adjusted for age, area, smoking, serum cholesterol, and alcohol intake. The patients had a slightly lower adjusted mean serum selenium than the subjects without cancer at the end of the follow-up (+/- standard error of mean) 53.9 +/- 1.5 and 55.3 +/- 0.5 micrograms/l, respectively. The relative risks of cancer were essentially the same when these were calculated in the tertiles of the serum selenium distribution. Thirty-seven men had a history of cancer at baseline or had cancer diagnosed during the first follow-up year and their adjusted mean serum selenium was 49.4 +/- 2.6 micrograms/l, which was significantly lower (P less than 0.05) than that of the subjects without cancer during the follow-up.