A new kinetic spectrophotometic method for the determination of trace amount manganese(II) in Tea real samples has been described based on it s the catalytic effect on the oxidations of 1 - (2 – Pyridyl Azo) - 2 - Naphthol, (PAN), by potassium bromated in sulfuric acid. The reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 547.5 nm. Under the optimum con...

a new kinetic spectrophotometic method for the determination of trace amount chromium (iii) in teareal samples has been described based on it s the catalytic effect on the oxidations of 1 - ( 2 –pyridylazo ) - 2 - naphthol, (pan), by potassium bromated in sulfuric acid. the reaction is followedspec- trophotometrically by measuring the decrease in the absorbance at 469 nm. under the optimumcondi...

A new kinetic spectrophotometic method for the determination of trace amount Chromium (III) in Teareal samples has been described based on it s the catalytic effect on the oxidations of 1 - ( 2 –PyridylAzo ) - 2 - Naphthol, (PAN), by potassium bromated in sulfuric acid. The reaction is followedspec- trophotometrically by measuring the decrease in the absorbance at 469 nm. Under the optimumcondi...

a new kinetic spectrophotometic method for the determination of trace amount manganese(ii) in tea real samples has been described based on it s the catalytic effect on the oxidations of 1 - (2 – pyridyl azo) - 2 - naphthol, (pan), by potassium bromated in sulfuric acid. the reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 547.5 nm. under the optimum con...

introduction a large volume of sediments are dredged from water bodies such as ports, waterways and wetlands and deposited on land. sediments are typically polluted by contaminants such as heavy metals. metals in sediments are in soluble, carbonate bound, fe-mn oxide, sulfide/organic matter bound and residual fractions. the metal solubility and mobility are mainly controlled by organic matter c...

In this paper, we investigate the 2-adic valuation of the Stirling numbers S(n, k) of the second kind. We show that v2(S(2n + 1, k + 1)) = s2(n) − 1 for any positive integer n, where s2(n) is the sum of binary digits of n. This confirms a conjecture of Amdeberhan, Manna and Moll. We show also that v2(S(4i, 5)) = v2(S(4i + 3, 5)) if and only if i 6≡ 7 (mod 32). This proves another conjecture of ...

Let [Formula: see text] be a triangular array of numbers. We say that [Formula: see text] is skew log-concave if for any fixed n, the sequence [Formula: see text] is log-concave. In this paper, we show that the Boros-Moll sequences are almost skew log-concave.

BACKGROUND In single photon emission computed tomography [SPECT], high specific activity of 111In-labelled tracers will allow administration of low amounts of tracer to prevent receptor saturation and/or side effects. To increase the specific activity, we studied the effect of the buffer used during the labelling procedure: NaAc, NH4Ac, HEPES and MES buffer. The effect of the ageing of the 111I...

The present study describes a simple and highly selective method for separation, preconcentration and spectrophotometric determination of extremely low concentrations of lead. It is based on flotation of a complex of Pb(2+) ions and Alizarin yellow between aqueous and n-hexane interface at pH = 6. The proposed procedure is also applied for determination of lead in both tap water and prepared se...