An instrument and a method for simultaneously testing a molecular weight distribution and an organic nitrogen level of a water sample are provided. The instrument comprises: a tail-end injection valve, a chromatographic column, a pressure relief valve, an acid-adding injection valve, an oxygen-adding injection valve, a helical tube for an acid-oxygen reaction, a CO.sub.2 remover, a UV digester, a second gas-water separator membrane, a buffer solution injection valve, a helical tube for a buffer solution reaction, a cadmium column, a chromogenic agent injection valve, a helical tube for a chromogenic agent reaction, and a UV detector, sequentially connected via a pipeline. The tail-end injection valve is for receiving a fluid phase and a sample. The second gas-water separator membrane is connected to an electrical conductivity-based CO2 detector. The UV detector and the electrical conductivity-based CO.sub.2 detector are connected to a data processing computer.

A detector for a liquid chromatograph, includes a detector that detects components in liquid, a pipe that guides liquid to the detector, a casing that contains at least part of the pipe and the detector and has a bottom portion, and a thermal insulator provided on the bottom portion in the casing, wherein a discharge port is provided in the bottom portion of the casing, the thermal insulator has an upper surface and a lower surface, a first opening is provided in the upper surface of the thermal insulator, and a second opening is provided in the lower surface of the thermal insulator to overlap with the discharge port in a plan view, a flow path that guides liquid from the first opening to the second opening is provided in the thermal insulator, and the flow path has a bend portion.

A flow cell for a detector in a liquid chromatography system includes a flow cell body, an inlet, an outlet, at least two windows situated on opposing sides of the flow cell body, which are transparent for light, and at least two electrodes configured for a conductivity measurement. A detection channel is formed within said flow cell body, fluidly connecting said inlet and outlet, includes an optical path situated in between said two windows such that a light absorption measurement may be performed for a liquid passing through the detection channel, and a conductivity path formed by at least partially drilling through said electrodes to allow for a physical contact of a liquid passing through the detection channel. A detector or liquid chromatography system including such a flow cell as well as uses of the flow cell, detector or liquid chromatography system are also described.

An electrical conductivity detector includes a cell through which a liquid flows, a measurement part for obtaining an electrical conductivity signal which is a current corresponding to an electrical conductivity of the liquid flowing through the cell, a phase adjustment value holder that holds a phase adjustment value which is a predetermined shift amount between a phase of the electrical conductivity signal and a phase of a measurement voltage applied to the cell by the measurement part, a BG subtraction signal generator configured to generate a BG subtraction signal for removing a background component included in the electrical conductivity signal obtained by the measurement part, the BG subtraction signal being adjusted to have a phase substantially identical to the phase of the electrical conductivity signal using the phase adjustment value held in the phase adjustment value holder, an addition part configured to add the electrical conductivity signal and the BG subtraction signal with each other, and a calculation part configured to calculate the electrical conductivity of the liquid flowing through the cell using a signal output from the addition part.

Described herein are the amphetamine-related compounds amphetamine carbamate (amphetammonium-amphetacarbamate) and amphetacarbamate, methods of making them, methods for detecting or quantitatively determining the amount of amphetacarbamate or amphetamine carbamate in a compositions, and ion chromatography columns useful in such methods.

A detector for a liquid chromatograph, includes a detector that detects components in liquid, a pipe that guides liquid to the detector, a casing that contains at least part of the pipe and the detector and has a bottom portion, and a thermal insulator provided on the bottom portion in the casing, wherein a discharge port is provided in the bottom portion of the casing, the thermal insulator has an upper surface and a lower surface, a first opening is provided in the upper surface of the thermal insulator, and a second opening is provided in the lower surface of the thermal insulator to overlap with the discharge port in a plan view, a flow path that guides liquid from the first opening to the second opening is provided in the thermal insulator, and the flow path has a bend portion.

A detector for a liquid chromatograph includes a detector that detects components in liquid, and a heat exchanger that adjusts a temperature of liquid introduced into the detector, wherein the heat exchanger includes a pipe having a winding portion, and a cast in which the winding portion is embedded, the pipe is formed of resin, and the cast is formed of an alloy having a melting point lower than a continuous use temperature of the resin.

An electric conductivity detector includes at least a cell part having a cell through which liquid flows therein and measurement electrodes measuring a current of liquid flowing through the liquid in the cell, a detection circuit electrically connected to the measurement electrodes and configured to detect a current value flowing between the measurement electrodes, and to output a signal based on the detected value, and a processing unit configured to take in a signal output from the detection circuit and perform signal processing, in which the cell part and the detection circuit are configured to be accommodated in a column oven regulating a temperature of an analytical column of an ion chromatograph.

An electrical conductivity detector includes a cell through which a liquid flows, a measurement part for obtaining an electrical conductivity signal which is a current corresponding to an electrical conductivity of the liquid flowing through the cell, a phase adjustment value holder that holds a phase adjustment value which is a predetermined shift amount between a phase of the electrical conductivity signal and a phase of a measurement voltage applied to the cell by the measurement part, a BG subtraction signal generator configured to generate a BG subtraction signal for removing a background component included in the electrical conductivity signal obtained by the measurement part, the BG subtraction signal being adjusted to have a phase substantially identical to the phase of the electrical conductivity signal using the phase adjustment value held in the phase adjustment value holder, an addition part configured to add the electrical conductivity signal and the BG subtraction signal with each other, and a calculation part configured to calculate the electrical conductivity of the liquid flowing through the cell using a signal output from the addition part.

A detector for gas chromatography includes a manifold, a first bridge circuit, and a second bridge circuit. A first analysis flow path, a first reference flow path, a second analysis flow path, and a second reference flow path are formed in the manifold. The first bridge circuit is configured to be capable of detecting a predetermined component in a first analysis gas using the first analysis resistive body and the first reference resistive body. The second bridge circuit is configured to be capable of detecting a predetermined component in a second analysis gas using the second analysis resistive body and the second reference resistive body. The distance between the first analysis resistive body and the second reference resistive body is less than the distance between the first analysis resistive body and the second analysis resistive body.