A method for determining a state of a fluidic system can include measuring back pressures in the fluidic system at different times and determining a state of the fluidic system. The determination is based on at least the measured back pressures and on additional status information indicative of at least one status of the fluidic system at at least one of the different times.

A method for determining a state of a fluidic system can include measuring back pressures in the fluidic system at different times and determining a state of the fluidic system. The determination is based on at least the measured back pressures and on additional status information indicative of at least one status of the fluidic system at at least one of the different times.

The present invention relates to computer implemented method performed by a computer (110) configured to calibrate an apparatus for measuring the absorbance of light of a substance (131) for a chromatography system (100), the apparatus (131) comprising a conduit (C) for enabling a fluid to be measured, a light emitter (LE) configured to emit light along an optical path (OP) to a light sensor (S) configured to measure the emitted light, the optical path intersecting the conduit (C), a rotating disc (D) having one or more optical filters, each of the one or more optical filters is arranged with its center passing through the optical path (OP) when rotating, an actuator configured to rotate the disc (D) dependent on a control signal, to the method comprising controlling rotation of (710) the disc (D) to a first position where a first filter, of the one or more optical filters, intersects the optical path (OP) at a first point (P1), measuring (720) a first light absorption value, controlling rotation of (730) the disc (D) to a second position, different to the first position, where the first filter still intersects the optical path (OP) at a second point (P2), measuring (740) a second light absorption value, generating (750) an aggregated light absorption value, calibrating (760) the apparatus (131) by comparing the aggregated light absorption value to a reference light absorption value.

A heat insulating member 13 is provided on the outer circumference of a connection pipe 11. The heat insulating member 13 includes: a tube 12; and an air layer 15 between the connection pipe 11 and the tube 12. Accordingly, it is possible to always keep the temperature of a sample component at the time of detection by a detector constant and thus prevent an influence of the temperature on an output result of the detector, in a low flow rate analysis using a modularized column unit and a modularized detection unit.

This invention relates to a micro-device for detecting volatile compounds comprising: an input (E) and an output (S); collection means (2) for taking a gas sample containing at least one compound to be detected; sampling means enabling a gas volume of 100 mL or less to be sampled, arranged after the collection means; injection means (3) of said gas sample; separation means (5) of the compound to be detected in the gas sample; compound detection means (6); and a gas circulation circuit (1) located downstream of the collection means and passing through the sampling means, injection means (3), separation means (5) and detection means (6);

characterized in that the gas circulation circuit (1) has a volume of between 0.2 cm.sup.3 and 2.0 cm.sup.3.

This invention relates to a micro-device for detecting volatile compounds comprising: an input (E) and an output (S); collection means (2) for taking a gas sample containing at least one compound to be detected; sampling means enabling a gas volume of 100 mL or less to be sampled, arranged after the collection means; injection means (3) of said gas sample; separation means (5) of the compound to be detected in the gas sample; compound detection means (6); and a gas circulation circuit (1) located downstream of the collection means and passing through the sampling means, injection means (3), separation means (5) and detection means (6);

characterized in that the gas circulation circuit (1) has a volume of between 0.2 cm.sup.3 and 2.0 cm.sup.3.

An improved version of the capillary bridge viscometer that compensates for the effect of solvent compressibility is disclosed. A novel, yet simple and inexpensive modification to a conventional capillary bridge viscometer design can improve its ability to reject pump pulses by more than order of magnitude. This improves the data quality and allows for the use of less expensive pumps. A pulse compensation volume is added such that it transmits pressure to the differential pressure transducer without sample flowing there through. The pressure compensation volume enables the cancellation of the confounding effects of pump pulses in a capillary bridge viscometer.

An improved version of the capillary bridge viscometer that compensates for the effect of solvent compressibility is disclosed. A novel, yet simple and inexpensive modification to a conventional capillary bridge viscometer design can improve its ability to reject pump pulses by more than order of magnitude. This improves the data quality and allows for the use of less expensive pumps. A pulse compensation volume is added such that it transmits pressure to the differential pressure transducer without sample flowing there through. The pressure compensation volume enables the cancellation of the confounding effects of pump pulses in a capillary bridge viscometer.

Ion chromatography may be used for measuring the concentration of metal ions in various streams of a vinyl acetate production process. For example, a method may comprise: reacting ethylene, oxygen, and acetic acid in the presence of a catalyst and optionally a catalyst promotor like sodium acetate and/or potassium acetate to yield a crude vinyl acetate stream; measuring a concentration of a metal ion of the crude vinyl acetate stream and/or a stream downstream thereof with an ion chromatograph, wherein the metal ion is selected from the group consisting of Group I metal ions, Group II metal ions, transition metal ions, and any combination thereof.

Ion chromatography may be used for measuring the concentration of metal ions in various streams of a vinyl acetate production process. For example, a method may comprise: reacting ethylene, oxygen, and acetic acid in the presence of a catalyst and optionally a catalyst promotor like sodium acetate and/or potassium acetate to yield a crude vinyl acetate stream; measuring a concentration of a metal ion of the crude vinyl acetate stream and/or a stream downstream thereof with an ion chromatograph, wherein the metal ion is selected from the group consisting of Group I metal ions, Group II metal ions, transition metal ions, and any combination thereof.