Einsatz organischer Lösungsmittel in Laborgefriertrocknern
Freeze-dryers were initially intended to be used with water as a solvent. With new applications, freeze-drying is consequently being used more and more in combination with organic solvents instead of water. Organic solvents and inorganic acids and bases are often used in research and development prior to lyophilisation of the sample. The behavior of these new types of samples during freeze-drying must therefore be considered prior to the process.
Stickstoffbestimmung in pharmazeutisch aktiven Peptiden
Die Bestimmung des Stickstoff- und Gesamtproteingehaltes in pharmazeutischen Produkten wird im Europäischen Arzneibuch (Ph.Eur.) in den Abschnitten 2.5.9 und 2.5.33 Methode 7 beschrieben [1, 2]. In der US-Pharmakopöe (USP) ist die Stickstoffbestimmung in Abschnitt 461 beschrieben [3]. Die Ph.Eur. sieht die Rücktitration unter Verwendung eines Methylrot-Mischindikators vor, die USP verwendet die potenziometrische Borsäure-Titration.
Sulfated Ash Determination for Pharmaceutical Quality Control
The wet digestion is used to remove all carbonous material from the sample. The remaining inorganic content can be weighed out, resulting in the sulfated ash, or then be used for further elemental analysis. The digestion is performed using concentrated sulfuric acid while heating the mixture. The heat is ramped automatically using the BUCHI Wet Digester B-440. Once the sulfuric acid has digested the sample and is evaporated, the sample is eventually ashed in a muffle oven to remove any remaining organic material.