Reagents, analytical grade

Maleic anhydride, a Fluka reagent analytical grade, was used without further purification. 

One millilitre of this solution is equivalent to about 20 pg of lead. The solution should be freshly prepared using the analytical-grade reagent, ideally taken from a new or recently opened reagent bottle. 

Notes. (1) The reagent solution should be freshly prepared using analytical-grade dithizone and 1,10-phenanthroline, preferably taken from new or recently opened reagent bottles. 

Reagent I. This consists of 0.12 M hydrochloric acid containing 100 g of analytical-grade sodium chloride per litre. 

Zinc-ion solution. Dissolve about 7.0 g of analytical grade zinc sulphate heptahydrate in 25 mL of Reagent I. 

Reagents. Standard copper (II) solutions. Dissolve 100 mg of spectroscopically pure copper metal in a slight excess of nitric acid and dilute to 1 L in a graduated flask with de-ionised water. Pipette a 10 mL aliquot into a 100 mL graduated flask and make up to the mark with acetone (analytical grade) the resultant solution contains 10 g of copper per mL. Use this stock solution to... 

Solutions of cerium(IV) sulphate may be prepared by dissolving cerium(IV) sulphate or the more soluble ammonium cerium(IV) sulphate in dilute (0.5-1.0M) sulphuric add. Ammonium cerium(IV) nitrate may be purchased of analytical grade, and a solution of this in 1M sulphuric add may be used for many of the purposes for which cerium(IV) solutions are employed, but in some cases the presence of nitrate ion is undesirable. The nitrate ion may be removed by evaporating the solid reagent which concentrated sulphuric add, or alternatively a solution of the nitrate may be predpitated with aqueous ammonia and the resulting cerium(IV) hydroxide filtered off and dissolved in sulphuric acid. 

Procedure. Prepare an approx. 0.02M standard solution of potassium bromate by weighing accurately about 1.65 g of the analytical grade reagent, dissolving it in water and making it up to 500 mL in a graduated flask (Note 2). 

Reagents. Supporting electrolyte. Prepare 0.2M potassium bromide from the analytical grade salt. 

Reagents. Standard lead solution. Dissolve 0.160 g of analytical grade lead nitrate in 1 L of distilled water 10.0 mL of this solution, diluted to 250 mL gives a working solution containing 4 pg of lead mL"1. 

Reagents. Potassium dichromate. 0.002 M, 0.001M, and 0.0005 M in 1M sulphuric acid and 0.7M phosphoric( V) acid, prepared from the analytical grade reagents. 

Reagents. Copper ion solution, 0.04M. Wash analytical grade copper with petroleum spirit (b.p. 40-60 °C) to remove any surface grease and dry at 100 °C. Weigh accurately about 1.25 g of the pure copper, dissolve it in 5mL of concentrated nitric acid, and dilute to 1 L in a graduated flask. Titrate this... 

It should also be emphasised that unless otherwise stated all reagents employed in the analytical procedures should be of appropriate analytical grade or spectroscopic grade materials. Similarly, where solutions are prepared in water this automatically means distilled or deionised water from which all but very minor impurities will have been removed. 

Analytical-grade (pro analyst) sodium cyanide was purchased by the submitters from Merck, Darmstadt, Germany, and dried for 24 hours in a vacuum desiccator containing potassium hydroxide pellets. The checkers obtained sodium cyanide from Fisher Scientific Company and dried the reagent in the same manner. 

To prepare 1000 pgmL individual metabolite solutions, weigh O.lOOOiO.OOlOg (weight adjusted for purity of free acid) of each analytical-grade metabolite into individual 100-mL volumetric flasks. Dilute the contents to volume with absolute ethanol, and mix the contents to ensure complete dissolution. Dilute equal amounts of each metabolite solution to the appropriate volume with reagent water to prepare a 1.0 pg mL mixed metabolite solution, a 100.0 pgL mixed metabolite solution, and a 10.0 pg L mixed metabolite solution. The concenttation values of the mixed metabolite solutions refer to each individual metabolite within the mixture. 

Brines Analytical grade sodium chloride, purity 99.9% was obtained from BDH and used throughout the study. Water was purified by reverse osmosis, and deionised in a Milli-Q-Reagent system immediately prior to use. 

All solutions are made in bidistilled water by dissolving the required quantities of analytical-grade reagents. Pure nitrogen gas is bubbled through the solutions to get rid of dissolved oxygen. 

The other reagents, commercially available, were of analytical grade. All the solutions of these materials were made with deionized and distilled water, using an all-Pyrex apparatus. 

All reagents were of analytical grade or better. Ace-K, Apt, Sac, Cyclamate-Na (Cyc-Na) and Vit C were kindly supplied from Ulker Gida Comparer, Turkey. H3P0 (85%), n-butyl alcohol were supplied from Merck (Darmstadt, Germany). 

Reagents. All reagents were of analytical grade, unless mentioned otherwise. 

Materials. All reagents were analytical grade. Solutions were prepared in demineralized water. Central incisors were extracted from lower jaws of four-year old cows obtained from a local slaughterhouse. Pentosidine was a kind gift from Prof. V. Monnier, Case Western Reserve University, Cleveland OH, USA. Furosine was from Neosystem, Strasbourg, France, and hydroxylysylpyridinoline and lysylpyridinoline from Metra Biosystems, Palo Alto CA, USA. 

Isooctane, acetone, and sodium hydroxide were obtained from Merck (Mollet del Valles, Barcelona, Spain). All the solvents and reagents were analytical grade. 

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