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The method consists in ashing of a test portion in a muffle furnace at 525+25 C, treating the ash obtained with hydrochloric acid, neutralizing with ammonia solution and determing of the value using an ammonia/ammonium chloride electrolyte. Copper, tin, lead and cadmium do not interfere.
Fruits, vegetables and derived products; Determination of zinc content; Part 1 : Polarographic method
The method consists in quantitative entraining by steam of the acid present in a test portion and reducing of mercury(II)chloride by the acid to mercury(I)chloride, followed by determing of the acid content from the yield of the mercury(I)chloride.
Fruit and vegetable products; Determination of formic acid content; Part 1 : Gravimetric method
Fruits, Vegetables and Derived Products - Determination of Ascorbic Acid Content - Part 2: Routine Methods First Edition; (Withdrawn)
The method consists in quantitative entraining by steam of the acid present in a test portion, determing of the amount of iodine equivalent to the amount of bromine consumed by the acid in the distillate, by titration with sodium thiosulfate standard volumetric solution.
Fruit and vegetable products; Determination of formic acid content; Part 2 : Routine method
The method consists in decomposing the organic matter in a nitric acid medium at high temperature and under pressure, and determining the lead(II) cation with a suitable spectrometer after the addition of orthophosphoric acid.
Fruits, vegetables and derived products; Determination of lead content; Flameless atomic absorption spectrometric method
The method consists in decomposing of organic matter in a sulfuric-nitric acid medium, reducing of mercury(II) to metallic mercury by the action of tin(II)chloride, entraining of the mercury vapour by a current of air and determing in an enclosed apparatus.
Fruits, vegetables and derived products; Determination of mercury content; Flameless atomic absorption method
Fruits, vegetables and derived products; Determination of cadmium content; Flameless atomic absorption spectrometric method
The method consists in extracting the acid from an acidified test portion using diethyl ether, nitrating followed by reduction and Mohler's reaction modified with hydroxylaminehydrochloride, measuring the absorbance of the red complex obtained with a suitable spectrometer. For determining lower concentrations, see ISO 5518.
Fruit and vegetable products; Determination of benzoic acid content (benzoic acid contents greater than 200 mg per litre or per kilogram); Molecular absorption spectrometric method
The method consists in decomposing a test portion, reducing arsenic (V) to arsenic (III) with tin(II) chloride and transforming the arsenic into arsine by action of nascent hydrogen, forming a red coloured complex by the action of the arsine on silver diethyldithiocarbamate and measuring at a wavelength of 520 nm.
Fruits, vegetables and derived products; Determination of arsenic content; Silver diethyldithiocarbamate spectrophotometric method
The method consists in acidifying a test portion with tartaric acid, entraining the volatile acids by steam distillation and titrating the distillate with standard volumetric sodium hydroxide solution in the presence of phenolphthalein as an indicator. The method is applicable to all fresh products, to products preserved without chemical preservatives, and to products to which sulphur dioxide has been added.
Fruits, vegetables and derived products; Determination of volatile acidity
The method consists is decomposing of organic matter by a dry or wet method and determing of the Zn + cation by a suitable spectrometer. For some liquid samples the determination may be carried out directly, without previous decomposition.
Fruits, vegetables and derived products; Determination of zinc content; Part 2 : Atomic absorption spectrometric method
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