Zur Bestimmung von Silber

Ohne Zusammenfassung     

Zur Bestimmung von Phosphor in organischen Substanzen

Ohne Zusammenfassung     

Zur gravimetrischen Bestimmung von Kupfer und Nickel

Ohne Zusammenfassung     

Zur Bestimmung Ton Eisen(II) und Eisen(III) nebeneinander in Mineralien, Erzen und Konzentraten

Ohne Zusammenfassung     

Mikrobestimmung von Kaliumjodid in Vollsalz

Ohne Zusammenfassung     

Zur Bestimmung von Germanium

Ohne Zusammenfassung     

Eine neue Methode zur Bestimmung des Kupfers in stark gef?rbten Alkohol-Wassergemischen (Branntwein)

Ohne Zusammenfassung     

Continuous glucose monitoring by means of mid-infrared transmission laser spectroscopy in vitro

The continuous surveillance of glucose concentration reduces short-term risks and long-term complications for people with diabetes mellitus, a disorder of glucose metabolism. As a first step towards the continuous monitoring of glucose, reagent-free transmission spectroscopy in the mid-infrared region has been carried out in vitro using a quantum cascade laser and an optical silver halide fiber. A 30 μm gap in the fiber allowed for transmission spectroscopy of aqueous glucose solutions at a wavelength of 9.69 μm, which is specific to a molecular vibration of glucose. A noise-equivalent concentration as low as 4 mg/dL was achieved at an average power of 1.8 mW and an integration time of 50 s. This is among the most precise of glucose measurements using mid-infrared spectroscopy. Even with the very low average laser power of 0.07 mW the sensitivity of previous results (using a fiber optical evanescent field analysis) has been improved upon by almost one order of magnitude. Finally, the impact of potentially interfering substances such as other carbohydrates was analyzed.