Abstract: A method for the determination of the amount of cholesterol in lipoproteins other than high density lipoproteins in a lipoprotein-containing sample, said method comprising (a) electrochemically determining the amount of cholesterol bound to high density lipoproteins in the sample, (b) electrochemically determining the total amount of cholesterol in the sample, and subtracting the result of (a) from the result of (b).

Abstract: In an electrochemical sensor, the potential difference applied to the electrochemical cell is raised to a measuring value at a rate determined to reduce the transient current. The maximum rate of change of the voltage is set to prevent saturation of an IE converter. The electrochemical cell may contain micro-electrodes as working and reference electrodes. The method may be applied to a battery powered, handheld device.

Abstract: A target substance (8) is subject to a freeze drying process in which the substance is first passed into a freeze chamber (31) to reduce the temperature of the substance, and then passed into a separate vacuum chamber (32) in which a vacuum is applied to promote drying of the target substance. Because the carrier (10) and target substance (8) is moved from a freeze chamber (31) to a separate vacuum chamber (32) the environment can be more closely controlled and the cycling of freezing to drying can be more rapid. In this way the carrier (10) and target substance (8) is subject to the full temperature cycling without the surrounding chamber and apparatus being subject to the full cycle. This reduces time and energy costs. The technique is particularly suited to manufacturing biosensors using freeze dried reagents.

Abstract: A method for the determination of the amount of cholesterol in high density lipoproteins in a high density lipoprotein containing sample, the method comprising reacting the sample with a PEG-ylated protein to selectively complex non-HDL lipoproteins in the sample with the PEG-ylated protein, or with a PEG-ylated enzyme capable of selective reaction with high density lipoproteins, and subsequently measuring the amount of cholesterol in the high density lipoproteins, for example using an electrochemical technique.