Abstract: A gas transfer system for transferring gas into an analytical instrument for isotope ratio analysis comprises a capillary for delivering sample and/or reference gas from a gas source, a first connector for connecting the capillary to the gas source, a second connector for connecting the capillary to the analytical instrument, a crimping device, wherein the internal surface of the capillary comprises a coating material to prevent or minimize adsorption of water to the surface. Also provided is a device for regulating gas flow in a gas inlet system of an analytical instrument, comprising a body member having an internal gas flow channel, and a clamping member for attachment to the body member such that when the clamping member is tightened onto the body member, the internal gas flow channel is adjustably and reversibly crimped, to adjust gas flow therethrough.

Abstract: An isotope ratio spectrometer is operated for measurement of a sample. First isotope ratios and first signal intensities are measured for a reference in the spectrometer, over a first measurement time period. A first relationship comprising a relationship between the first isotope ratios and the first signal intensities is determined. Sample isotope ratios and sample signal intensities are measured in the spectrometer, over a second measurement time period subsequent to the first measurement time period. Second isotope ratios and second signal intensities for a reference are measured in the spectrometer, over a third measurement time period subsequent to the second measurement time period. A second relationship comprising a relationship between the second isotope ratios and the second signal intensities is determined. A reference isotope ratio is estimated for a time X within the second measurement time period, based on the first relationship and the second relationship.

Abstract: An isotope ratio spectrometer is operated for measurement of a sample. First isotope ratios and first signal intensities are measured for a reference in the spectrometer, over a first measurement time period. A first relationship comprising a relationship between the first isotope ratios and the first signal intensities is determined. Sample isotope ratios and sample signal intensities are measured in the spectrometer, over a second measurement time period subsequent to the first measurement time period. Second isotope ratios and second signal intensities for a reference are measured in the spectrometer, over a third measurement time period subsequent to the second measurement time period. A second relationship comprising a relationship between the second isotope ratios and the second signal intensities is determined. A reference isotope ratio is estimated for a time X within the second measurement time period, based on the first relationship and the second relationship.

Abstract: A gas transfer system for transferring gas into an analytical instrument for isotope ratio analysis comprises a capillary for delivering sample and/or reference gas from a gas source, a first connector for connecting the capillary to the gas source, a second connector for connecting the capillary to the analytical instrument, a crimping device, wherein the internal surface of the capillary comprises a coating material to prevent or minimize adsorption of water to the surface. Also provided is a device for regulating gas flow in a gas inlet system of an analytical instrument, comprising a body member having an internal gas flow channel, and a clamping member for attachment to the body member such that when the clamping member is tightened onto the body member, the internal gas flow channel is adjustably and reversibly crimped, to adjust gas flow therethrough.

Abstract: A gas transfer system for transferring gas into an analytical instrument for isotope ratio analysis comprises a capillary for delivering sample and/or reference gas from a gas source, a first connector for connecting the capillary to the gas source, a second connector for connecting the capillary to the analytical instrument, a crimping device, wherein the internal surface of the capillary comprises a coating material to prevent or minimize adsorption of water to the surface. Also provided is a device for regulating gas flow in a gas inlet system of an analytical instrument, comprising a body member having an internal gas flow channel, and a clamping member for attachment to the body member such that when the clamping member is tightened onto the body member, the internal gas flow channel is adjustably and reversibly crimped, to adjust gas flow therethrough.

Abstract: An isotope ratio spectrometer is operated for measurement of a sample. First isotope ratios and first signal intensities are measured for a reference in the spectrometer, over a first measurement time period. A first relationship comprising a relationship between the first isotope ratios and the first signal intensities is determined. Sample isotope ratios and sample signal intensities are measured in the spectrometer, over a second measurement time period subsequent to the first measurement time period. Second isotope ratios and second signal intensities for a reference are measured in the spectrometer, over a third measurement time period subsequent to the second measurement time period. A second relationship comprising a relationship between the second isotope ratios and the second signal intensities is determined. A reference isotope ratio is estimated for a time X within the second measurement time period, based on the first relationship and the second relationship.

Abstract: A gas transfer system for transferring gas into an analytical instrument for isotope ratio analysis comprises a capillary for delivering sample and/or reference gas from a gas source, a first connector for connecting the capillary to the gas source, a second connector for connecting the capillary to the analytical instrument, a crimping device, wherein the internal surface of the capillary comprises a coating material to prevent or minimize adsorption of water to the surface. Also provided is a device for regulating gas flow in a gas inlet system of an analytical instrument, comprising a body member having an internal gas flow channel, and a clamping member for attachment to the body member such that when the clamping member is tightened onto the body member, the internal gas flow channel is adjustably and reversibly crimped, to adjust gas flow therethrough.

Abstract: A system for controlling flow of gas in a continuous flow isotope ratio analyser is provided. The system comprises gas inlet and gas outlet lines for providing gas into and from a measuring cell, and at least one switchable flow restriction on the gas inlet line, for selectively controlling gas flow into the isotope ratio analyser. Also provided is a method for determining an isotope ratio using the system according to the invention.

Abstract: A system for controlling flow of gas in a continuous flow isotope ratio analyser is provided. The system comprises gas inlet and gas outlet lines for providing gas into and from a measuring cell, and at least one switchable flow restriction on the gas inlet line, for selectively controlling gas flow into the isotope ratio analyser. Also provided is a method for determining an isotope ratio using the system according to the invention.