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[求助]
寻找有能力检验造影剂内钆含量（USP标准，原子吸收法）的单位
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您好！因公司有一个药品要出口，需用原子吸收测定钆的含量，如你有检测能力请联系我，检测费用站外商议。具体检测方法如下： Assay of gadolinium. Limit: 1 ml of the product should have 74.6 - 82.4 mg (95-105%) of gadolinium. The assay is performed by atom absorption spectroscopy. Reagents: 65% (w/w) nitric acid, Suprapur (Merck) or similar; 30% (w/w) hydrochloric acid, Suprapur (Merck) or similar; Water with ≤50 µS conductivity; 10% (w/v) cesium chloride Dissolve 10.00 g of cesium chloride Suprapur (Merck) in water with ≤50 µS conductivity contained in 100 ml volumetric flask and dilute to volume with the same solvent; Gadolinium (III) oxide solution working standard; 10000 mg Gd per liter Methods: Preparation of test solution: Expose 1.00 ml of product (v) in porcelain pot to 0.2 ml of 65% (w/w) nitric acid, evaporate on a hot stove, dry, ignite at approximately 500°C, then burn in muffle furnace at 800°C till black particles disappear (approximately 1 hour). Then leave the residue to cool to room temperature on fire-resistant surface. Dissolve the white residue at heating in 1.0 ml of water and 1.0 ml of 30% (w/w) hydrochloric acid, Suprapur (Merck) or similar. Put the solution quantitatively to 100 ml volumetric flask, add 10 ml of 10% (w/v) cesium chloride solution, dilute to volume with water with ≤50 µS conductivity. Preparation of gadolinium stock standard solution: Dissolve the weighting of 11.5260 g of gadolinium (III) oxide working standard (accurately weighted) (MR) in 25 ml of 30% (w/w) hydrochloric acid Suprapur (Merck) or similar in 1000 ml volumetric flask, then dilute to volume with water with ≤50 µS conductivity (C=~10 mg of gadolinium per ml). Preparation of gadolinium standard solutions 1, 2 and 3: Put 3.0 ml, 4.0 ml and 5.0 ml of gadolinium stock standard solution into individual 50 ml volumetric flasks, add 5.0 ml of 10% (w/v) cesium chloride solution and 0.5 ml of 30% (w/w) of hydrochloric acid, Suprapur (Merck) or similar, then dilute to volume with water with ≤50 µS conductivity (corresponds to 600 mg of gadolinium per liter, 800 mg gadolinium per liter and 1000 mg of gadolinium per liter respectively). Control test: Put 10.0 ml of 10% (w/v) cesium chloride solution into 100 ml volumetric flask, add 1.0 ml of 30% (w/w) hydrochloric acid, Suprapur (Merck) or similar and then dilute to volume with water ≤50 µS with conductivity. Chromatographic conditions: Device Atomic absorption flame spectrophotometer Measurement type Absorption with background compensation Light source Gadolinium hollow cathode lamp Conditioning time 15 minutes Measured wavelength 368.4 nm Opening width 0.2 nm Fuel gas Acetylene > 99.6% (v/v) free from solvent Oxidant Nitrous oxide >99.8% (v/v) Burner type Nitrous oxide burner Calibration method Linear Methods: Perform three quantifications of test solution and standard solutions 1, 2 and 3. Use average value of three quantifications for the calculation. |
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