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Date: 25-2-2018
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Date: 19-4-2017
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Date: 2-5-2017
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Choice of Proper Containers
The surface of the sample container may interact with the analyte. The surfaces can provide catalysts (e.g., metals) for reactions or just sites for irreversible adsorption. For example, metals can adsorb irreversibly on glass surfaces, so plastic containers are chosen for holding water samples to be analyzed for their metal content. These samples are also acidified with HNO3 to help keep the metal ions in solution. Organic molecules may also interact with polymeric container materials. Plasticizers such as phthalate esters can diffuse from the plastic into the sample, and the plastic can serve as a sorbent (or a membrane) for the organic molecules. Consequently, glass containers are suitable for organic analytes. Bottle caps should have Teflon liners to preclude contamination from the plastic caps.
Oily materials may adsorb strongly on plastic surfaces, and such samples are usually collected in glass bottles. Oil that remains on the bottle walls should be removed by rinsing with a solvent and be returned to the sample. A sonic probe can be used to emulsify oily samples to form a uniform suspension before removal for analysis.
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زراعة الأسنان.. بين بريق التجميل وحاجة المريض إليها
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وفاة أول رجل خضع لزراعة كلية خنزير.. والمستشفى يوضح الأسباب
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اختتام الأسبوع الثاني من الشهر الثالث للبرنامج المركزي لمنتسبي العتبة العباسية
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راية قبة مرقد أبي الفضل العباس (عليه السلام) تتوسط جناح العتبة العباسية في معرض طهران
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جامعة العميد وقسم الشؤون الفكرية يعقدان شراكة علمية حول مجلة (تسليم)
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قسم الشؤون الفكريّة يفتتح باب التسجيل في دورات المواهب
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