Abstract: Rapid characterization and screening of polymer samples to determine average molecular weight, molecular weight distribution and other properties is disclosed. Rapid flow characterization systems and methods, including liquid chromatography and flow-injection analysis systems and methods are preferably employed. High throughput, automated sampling systems and methods, high-temperature characterization systems and methods, and rapid, indirect calibration compositions and methods are also disclosed. In preferred high-temperature embodiments, the polymer sample is maintained at a temperature of not less than about 75° C. during sample preparation, loading into a liquid chromatography or flow-injection analysis system, injection into a mobile phase of a liquid chromatography or flow-injection analysis system, and/or elution from chromatographic column. The described methods, systems, and device have primary applications in combinatorial polymer research and in industrial process control.

Abstract: The invention concerns a method and an apparatus for the direct injection of large volumes (>3 &mgr;l) of samples into the column in a gas chromatography analysis apparatus comprising an oven, a gas chromatography column lodged in the oven, a means for the direct transfer into the column of the sample and a source of carrier gas upstream the column, as well as a detector downstream the column. According to the invention two or more of the parameters: nature of the solvent injection rate flow-rate and/or pressure of the carrier gas temperature at least of an initial length of the column during the injection are correlated and/or controlled to achieve a control of the length of the zone wetted by the sample during its introduction.

Abstract: To enable the mass injection of a sample in a gas chromatography and prevent occurrence of residue or decomposition of a desired constituent during analysis. The invention calls for providing the injection port with a liner, connecting the column and the liner to a press-fit, evaporating the solvent introduced into the liner, and discharging the evaporated solvent from a discharge port formed at the upper part of the liner.

Abstract: A sample concentration device is provided in which a gaseous sample is concentrated by cooling a portion of a gas transfer line through which the sample is introduced into a detecting apparatus, such as a gas chromatograph or the like. The device is characterized by a cooling device for cooling a portion of the gas transfer line, which is housed in a constant temperature chamber, by spraying a coolant from a nozzle facing the portion of the gas transfer line, and by a gas flow device for creating a substantially dry gas flow through the nozzle to prevent the nozzle from becoming plugged with ice formed by freezing of moisture in the air inside the constant temperature chamber when the coolant spray is stopped. An outer jacket surrounding a portion of the gas transfer line which is subjected to cooling is also disclosed.

Abstract: The invention relates to a method and device for preparing samples for gas chromatography, the sample material being guided through a liquid chromatograph (1) by means of a solvent and being monitoring by means of a detector (2), and, on the basis of the detector (2) recognizing a chromatographic region of interest, the sample material of this region being removed from the stream of sample material leaving the liquid chromatograph (1) and being analyzed by gas chromatography. In this case, the stream of sample material leaving the liquid chromatograph (1) is guided through a flow-through cuvette (4), and the removal is carried out, until the end of the chromatographic region of interest, via a syringe (18) which, when the sample material of the region of interest reaches the flow-through cuvette (4), is introduced into the stream of sample material guided through the flow-through cuvette (4) and is drawn upwards at a predetermined ratio to the transport rate of the stream of sample material.

Abstract: A sample inlet liner includes a novel matrix that serves to retain an injected sample. The preferred inert matrix is polytetrafluoroethylene (PTFE) that serves to retain an injected sample and is provided in lieu of a conventional packing material. The contemplated inert matrix may be selected from a range of configurations of PTFE so as to provide a supporting material capable of retaining an ample quantity of injected sample in the sample inlet liner. The contemplated matrix nonetheless provides a tortuous path for the retained quantity of injected sample so as to facilitate known injection techniques such as split/splitless injection and large volume injections.

Abstract: A device for carrying out solid phase microextraction is a tubular member having one closed end and one open end with an extracting surface within said tubular member. The extracting surface can be an extracting phase coating extending over a zone within the tubular member. The tubular member has a heater that can be used for either or both drawing fluid carrier into the tubular member or assisting in desorbing analytes into an injector of an analysis instrument. The tubular member can also be mounted in a housing with an airtight cavity and a plunger. A method of operation of the device is also provided. Previously, samples were analyzed using liquid-liquid extraction or using cartridges. Both of these methods are relatively expensive and time consuming. Both of these methods also require the use of solvents which can be difficult and expensive to dispose of.

Abstract: The invention relates to a method for the quantitative determination of deuterium in samples containing hydrogen, and to a reduction oven for reducing gaseous or liquid substances containing hydrogen, which may be coupled directly to an isotope ratio mass spectrometer (IRMS), thereby permitting an online-coupled, reliable deuterium determination which can be automatized.

Abstract: An injector for a gas chromatography system resistively heats an included cold trap by magnetically inducing a high-frequency current therethrough to inject absorbed analyte into a gas chromatography separation column. The injector includes a flow controller that is set initially to load analyte into the trap. A heater and a two-stage Peltier cooler are used to establish a sharp trough-shaped temperature gradient along the cold trap so that analyte loaded into the cold trap is absorbed only at a relatively cold "focussing" zone of the trap. Once the analyte is focussed, the flow controller is set to direct released analyte into the column. The magnetic-field generator includes a capacitor that is discharged to initiate cold-trap heating. An inverter converts the discharge to a 100,000 Hz waveform through a transformer primary coil. A magnetic core delivers the resulting alternating magnetic field through the cold trap.

Abstract: A gas chromatograph includes a carrier gas supply flow path to which a pressure sensor, resistance tube, and control valve are sequentially connected. A differential pressure sensor is situated on both sides of the resistance tube to measure the differential pressure. The control valve is controlled by a controlling portion through signals from the pressure sensor and differential pressure sensor to control a flow rate of a carrier gas. Thus, in the gas chromatograph, the flow rate of the carrier gas can be controlled without an expensive pressure regulator, and a pressure of the carrier gas to be supplied can be selected as desired.

Abstract: A gas chromatograph has a sample vaporization chamber connected to a column for vaporizing a liquid sample injected therein and introducing this vaporized liquid sample with a carrier gas into the column. There is also a flow rate control device for controlling the flow rate of the carrier gas either as it is being supplied into the vaporization chamber or as it is being discharged from the vaporization chamber through a discharge route other than the column for keeping the gas pressure approximately constant inside the vaporization chamber. A leakage detector detects a leakage of gas from the vaporization chamber on the basis of either a target value set for the flow rate control device or a monitored value of the flow rate. A warning device outputs a warning when a gas leakage is detected by the leakage detecting device.

Abstract: An automatic sample injector for injecting a liquid sample into a vaporization chamber of a gas chromatograph includes a syringe, a plunger adapted to move inside the barrel of this syringe, a stepping motor having a plurality of magnetic poles for moving the plunger up and down inside the barrel, a power source for supplying excitation currents to these magnetic poles, switches for these magnetic poles, and a control unit for controlling the switches or the power source such that the excitation current to one of a pair of the magnetic poles corresponding to a rotary angular position is increased and the excitation current to the other of the pair is simultaneously decreased.

Abstract: A microtrap sample concentrator useful for concentrating a sample of purged gas containing analytes for delivery to an analytical instrument, including: a tube containing at least one sorbent material which retains or traps analytes; where greater than 30% of all trapped analytes are directly delivered to an analytical instrument at a desorption flow rate of one to three cc/min, without splitting or cryogenic focusing the trapped analytes; where delivery of the trapped analytes to the analytical instrument is achieved by passing the trapped analytes through a passage being selectively connectable between the microtrap and the analytical instrument, the passage connected to a vent; where the temperature of the passage is not lower than ambient room temperature; and where the passage is heated to a temperature sufficient to vaporize water in the passage and to expel the vaporized water out of the vent.

Abstract: The invention relates to a method and a device to control the physical conditions of the solvent within a pre-column, in a gas chromatography analysis apparatus. To achieve desired and controlled conditions of recondensation in the pre-column with vaporization injectors or of vaporation with "on-column" injectors, the dew-point of the solvent in the pre-column is calculated and the factors which influence this dew-point are varied and/or the temperature of the pre-column is varied, in order to set such temperatures in a desired correlation.

Abstract: The invention concerns a device for automatically injecting substances solubilised or diluted in a solvent for a gaseous phase chromatographic analysis column (14), wherein it includes a concentration/calcination chamber (10), a vaporization chamber (12) in contact with the chromatographic column (14), a sample support (16) moving in the concentration/calcination chamber between a first position in which the sample is in the concentration/calcination chamber and a second position in which the sample is in the vaporization chamber, as well as a system (18) for scavenging the two chambers with a vector gas.

Abstract: An apparatus for sample concentration for gas chromatography and mass spectrometry for analysis for volatile organic compounds, including a hollow differential pressure switch to switch sample flow non-mechanically, and so that the gas chromatograph and apparatus may be used with different sample levels of volatile organic compounds by changing the timing and temperature parameters by changing the flow non-mechanically.

Abstract: A gas chromatograph for operation selectably in both split mode and splitless wide bore injection mode includes a capillary column, a sample injection chamber at the inlet of the column, a three-way valve, a first piping line connected between one of the two outlets of the three-way valve and the sample injection chamber, a split line connected to the sample injection chamber immediately upstream of the inlet of the column for discharging therethrough a portion of a gas being sent out from the sample injection chamber, a second piping line connected between the other of the outlets of the three-way valve and the split line, and a third piping line connected between the first and second piping lines. By properly controlling the total carrier gas flow rate and the column inlet pressure, the split ratio can be controlled easily. By varying the split ratio appropriately during an analysis, the amount of the carrier gas to be wasted in the case of a split mode of operation can be significantly reduced.

Abstract: In a method for extracting volatile substances from a vaporized liquid in which the vaporized liquid is withdrawn from an extraction chamber, a method of producing the vaporized liquid. The method includes the steps of introducing a carrier gas into the extraction chamber to form a vapor space, and spraying a liquid into the vapor space to form a vaporized liquid. An apparatus for practicing the method includes an extraction chamber in fluid communication with a liquid specimen source, and a liquid injection arrangement extending into the extraction chamber for spraying the liquid from the liquid specimen source in the vapor space to form a vaporized liquid. A carrier gas supply arrangement is provided adjacent to the extraction chamber for introducing carrier gas into the chamber to form a vapor space. The apparatus may further include a specimen chamber for collecting a predetermined amount of liquid prior to spraying.

Abstract: An injector with a vaporization chamber for gas chromatographic apparatus includes a heater to heat the chamber and a pierceable septum to seal an end of the chamber. At least a heat conducting element is removably mounted between the septum and the heater. One or more elements are positioned adjacent to the septum and are in fluid communication with a source of carrier gas and a discharge outlet. The elements define paths with forced run for washing the septum and for feeding the vaporization chamber.