ascorbic-acid and magnesium-nitrate

A method for the determination of total selenium in wheat and wheat flour using graphite furnace atomic absorption spectrometry (GFAAS) with palladium/ascorbic acid as a chemical modifier was studied. The effects of nickel nitrate, palladium/ascorbic acid, and palladium/magnesium nitrate as chemical modifiers on the sensitivity in the determination of selenite, selenate and selenomethionine by GFAAS were compared. The palladium/ascorbic acid modifier was used for the determination of total selenium in wheat and wheat flour, because the oxidation states of the selenium ion are not important in the determination. The detection limit was estimated to be 1 microg L(-1) (calculated as 3sigma of the blank); the calibration curve was linear for the concentration range 5 - 50 microg L(-1) and the recovery range was 96.66 - 101.80%. The optimal ashing and atomizing temperatures were 1300 degrees C and 2250 degrees C, respectively. The proposed method was successfully applied to the determination of total selenium in wheat and wheat flour.

Topics: Ascorbic Acid; Flour; Magnesium Compounds; Nickel; Nitrates; Palladium; Romania; Selenium; Spectrophotometry, Atomic; Triticum

Manganese-induced early biochemical changes and effects of supplementation of magnesium nitrate (Mg(NO3)2) and antioxidant vitamins (A, C, D and E) were studied in rats intoxicated with manganese. Significant elevation in the level of chlorides in plasma, erythrocytes, liver and cerebellum, and a decrease in plasma inorganic phosphate (pi) with an increase in liver pi were observed in animals exposed to manganese as compared to controls. The level of erythrocyte-acid labile phosphate (ALP), nicotinamide adeninedinucleotide (NAD+) and plasma sialic acid (N-acetylneuraminic acid, NANA) also increased significantly. Elevated levels of chlorides in plasma, erythrocytes and cerebellum reversed to normal control values whereas liver chlorides restored partially by the supplementation of Mg(NO3)2. Vitamins supplementation was effective to reverse chlorides level in erythrocytes, liver and cerebellum. Decreased level of pi in plasma and the highly elevated level of erythrocyte ALP were also recovered in animals received Mg(NO3)2 in addition to MnSO4. However, such effect of Mg(NO3)2 was not seen in lowering the elevated level of NANA that restored by the administration of vitamins. Thus, the early alterations in plasma levels of chlorides, pi, and NANA and erythrocyte-ALP seem to be an indicative of early manganese toxicity while Mg(NO3)2 and vitamins supplementation appear to provide, at least in part, protection against manganese toxicity.

Topics: Animals; Antioxidants; Ascorbic Acid; Dietary Supplements; Magnesium Compounds; Male; Manganese; Nitrates; Rats; Time Factors; Vitamin A; Vitamin D; Vitamin E