الفهرس 
The production of a vaccineOnly 14 pages are availabe for public view
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Abstract
Catalytic methods of analysis are very popular examples for the application of kinetics in analytical chemistry. Their sensitivities are generally orders of magnitude better than conventional equilibrium methods. Therefore, they found recent widespread applications in many fields; especially in environmental and biochemical studies.
In the present work, three new spectrophotometric methods were developed for trace level determination of mercury, silver and palladium. These methods were applied to the analysis of biological products and Waste waters.
A simple, highly selective and sensitive method was developed for the determination of Hg2+ in inactivated vaccines , sea water, Nile river water, Food salt and Mercury lamps. The proposed method depends upon the substitution of cyanide ions of hexacyanoferrate (II) by isonicotinoyl hydrazide (isoniazide, INH). It was observed that colorless INH reacts with the yellow ferrocyanide in buffered solutions of pH 3.30 ± 0.10 to give an intense orange-yellow colored product. Although the color formation was relatively slow, the addition of small amounts of mercury (II), mercury (I) ions considerably accelerated the color development, especially upon following the proper reaction conditions.
The reaction was followed spectrophotometrically by tracing the formation of the orange-yellow product, which exhibit a maximum absorbance at 423 nm, using the initial rate method (tangent method). The optimum reaction conditions are 5.0 mmol L-1ferrocyanide, 0.2 mmolL-1 thiourea, 0.5 mmol L-1 INH, 0.15 mol L-1 citrate buffer (pH 3.30 ± 0.10), at 50 oC. The activation energy for the uncatalyzed reaction was 26.8 kcal.mol-1, whereas that for the reaction catalyzed by 60 ng mL-1 Hg2+ was 21.9 kcal.mol-1, showing efficient catalysis. The linear range of the calibration graph was up to 100ng mL-1 Hg2+ and 55 ng mL-1 Hg+ and the detection limits were 1.2 and 1.8 ng mL-1 for [Hg2+] and [Hg+] ions. The effects of potential interfering species and masking agents were studied experiments showed that elimination of the strong interference of Ag+ ions by its precipitation with Cl- or Br- ions depended on the initial concentration of both the halide and Ag+ ions and the digestion time.
In comparison with the high cost techniques including neutron activation analysis, improved AAS techniques, and ICP mass spectrometry for Hg-determination, the present work describes a very selective, simple, sensitive and low-cost method that can monitor as low as 1.2 ng mL-1 Hg2+ without any preconcentration step. The advantageous sensitivity and selectivity make the proposed method a favorable competitive to the dithizone or hydride generation (standard methods). A comparison of published catalytic - spectrophotometric methods based on ligand exchange reactions was also presented.