Device for detecting gas in a high-voltage apparatus filled with an insulating medium, comprising: - an inlet for introducing and an outlet for discharging a carrier gas; - at least one gas sensor for detecting a gas; - a first pump for conveying the carrier gas in the device; - a membrane which consists of at least one semi-permeable material, is at least partially surrounded by the insulating medium and is at least partially flowed against by the carrier gas; - a second pump for conveying the carrier gas into the device and for conveying it out of the device; characterized in that - a separating column is provided which is arranged in front of the gas sensor and the gas sensor is designed as a sensor array; - a valve with at least two operating states; - a measuring chamber in which sensors for temperature, humidity, pressure and the at least one gas sensor are arranged; wherein - the diaphragm is connected on the one hand to a first connection (20.1) via a first connecting line and on the other hand to a second connection (20.2) of the valve via a second connecting line; - the first pump is arranged in the first connecting line; - a fourth connecting line connects the separating column to the measuring chamber via a fourth connection (20.4) of the valve; - the measuring chamber is connected to an outlet via a second line; - a sample loop is connected via a third connecting line to a third connection (20.3) and a fourth connecting line to a fifth connection (20.5) of the valve. - an inlet for introducing and an outlet for discharging a carrier gas; - at least one gas sensor for detecting a gas; - a first pump for conveying the carrier gas in the device; - a membrane which consists of at least one semi-permeable material, is at least partially surrounded by the insulating medium and is at least partially flowed against by the carrier gas; - a second pump for conveying the carrier gas into the device and for conveying it out of the device; characterized in that - a separating column is provided which is arranged in front of the gas sensor and the gas sensor is designed as a sensor array; - a valve with at least two operating states; - a measuring chamber in which sensors for temperature, humidity, pressure and the at least one gas sensor are arranged; wherein - the diaphragm is connected on the one hand to a first connection (20.1) via a first connecting line and on the other hand to a second connection (20.2) of the valve via a second connecting line; - the first pump is arranged in the first connecting line; - a fourth connecting line connects the separating column to the measuring chamber via a fourth connection (20.4) of the valve; - the measuring chamber is connected to an outlet via a second line; - a sample loop is connected via a third connecting line to a third connection (20.3) and a fourth connecting line to a fifth connection (20.5) of the valve. - the diaphragm is connected on the one hand to a first connection (20.1) via a first connecting line and on the other hand to a second connection (20.2) of the valve via a second connecting line; - the first pump is arranged in the first connecting line; - a fourth connecting line connects the separating column to the measuring chamber via a fourth connection (20.4) of the valve; - the measuring chamber is connected to an outlet via a second line; - a sample loop is connected via a third connecting line to a third connection (20.3) and a fourth connecting line to a fifth connection (20.5) of the valve.