Abstract: A method of performing experiments on samples may include receiving criteria defining a starting state for performing an experiment in a system including a scientific instrument; determining whether the starting state is established in the system; and, responsive to the starting state being established, allowing the experiment, that analyzes a sample using the scientific instrument, to proceed. Determining whether the starting state is established may include automated monitoring of at least one parameter for at least one data channel, and determining whether all such parameters simultaneously meet associated conditions of the criteria for specified time periods. The method may include automatically monitoring the system and re-establishing the starting state prior to performing each of one or more subsequent experiments. The method may include automatically monitoring and establishing a second starting state prior to performing each of one or more additional experiments.

Abstract: A chromatography system includes a gradient delay volume defined as an overall fluid volume between where gradient is proportioned until an inlet of a chromatography column, a pump pumping a flow of gradient; and at least one valve located downstream from the pump, the at least one valve having a plurality of ports including an inlet port that receives the flow of gradient from the pump and an outlet port through which the flow of gradient exits the at least one valve, the at least one valve having at least two positions. A first position of the at least two positions of the at least one valve increases the gradient delay volume of the chromatography system relative to when the at least one valve is in a second position.

Abstract: A method for injecting a diluted sample in a chromatography system includes merging a flow of a sample and a flow of a diluent to form a flow of a diluted sample. A dilution ratio of the diluted sample equals a sum of the volumetric flow rates of the sample and the diluent divided by the volumetric flow rate of the sample. The diluted sample is stored in a holding element before injection into a chromatographic system flow. Sample dilution occurs under low pressure relative to the chromatographic flow thereby allowing lower pressure sample and diluent syringes to be used. Other benefits include reduced compressibility and a reduction in leaks due to the lower pressure operation. The method avoids problems associated with manual techniques which can introduce errors due, for example, to loss of sample, sample precipitation and adsorption of sample to vials.

Abstract: A chromatography system includes a gradient delay volume defined as an overall fluid volume between where gradient is proportioned until an inlet of a chromatography column, a pump pumping a flow of gradient; and at least one valve located downstream from the pump, the at least one valve having a plurality of ports including an inlet port that receives the flow of gradient from the pump and an outlet port through which the flow of gradient exits the at least one valve, the at least one valve having at least two positions. A first position of the at least two positions of the at least one valve increases the gradient delay volume of the chromatography system relative to when the at least one valve is in a second position.

Abstract: A chromatography system has an associated system volume and a sample dispersion volume. The chromatography system comprises a pump pumping a flow of gradient, a sample manager for introducing a sample into the flow of gradient, and a valve manager fluidically coupled to the pump and to the sample manager. The valve manager includes at least one valve. A first valve of the at least one valve has a plurality of ports including an inlet port that receives the flow of gradient from the pump and an outlet port through which the flow of gradient exits the first valve. The first valve has at least two different, automatically selectable positions. A first position of the at least two different automatically selectable positions operating to change one of the system and sample dispersion volumes of the chromatography system when the first valve is automatically switched into the first position.

Abstract: The invention generally provides methods for improving the dynamic range of an absorbance detector and absorbance detectors having improved dynamic range. In an exemplary embodiment, the method includes receiving calibration data for a plurality of samples, the calibration data comprising an absorbance for a concentration of each of the samples, calculating a contribution of stray light to the calibration data, and correcting subsequent data by removing the contribution of stray light.

Abstract: A method for injecting a diluted sample in a chromatography system includes merging a flow of a sample and a flow of a diluent to form a flow of a diluted sample. A dilution ratio of the diluted sample equals a sum of the volumetric flow rates of the sample and the diluent divided by the volumetric flow rate of the sample. The diluted sample is stored in a holding element before injection into a chromatographic system flow. Sample dilution occurs under low pressure relative to the chromatographic flow thereby allowing lower pressure sample and diluent syringes to be used. Other benefits include reduced compressibility and a reduction in leaks due to the lower pressure operation. The method avoids problems associated with manual techniques which can introduce errors due, for example, to loss of sample, sample precipitation and adsorption of sample to vials.

Abstract: A method of performing experiments on samples may include receiving criteria defining a starting state for performing an experiment in a system including a scientific instrument; determining whether the starting state is established in the system; and, responsive to the starting state being established, allowing the experiment, that analyzes a sample using the scientific instrument, to proceed. Determining whether the starting state is established may include automated monitoring of at least one parameter for at least one data channel, and determining whether all such parameters simultaneously meet associated conditions of the criteria for specified time periods. The method may include automatically monitoring the system and re-establishing the starting state prior to performing each of one or more subsequent experiments. The method may include automatically monitoring and establishing a second starting state prior to performing each of one or more additional experiments.

Abstract: A method for controlling fluid flowing through a chromatographic system includes determining a fluidic parameter related to density at a first fluidic location in the chromatographic system; and in response to the determined fluidic parameter, modifying a volumetric flow rate or a pressure at a second fluidic location in the chromatographic system to produce a selected mass flow rate of the fluid.

Abstract: A method of preparing a liquid mixture for use in a liquid chromatography system is provided. The mixture comprises one or more acids, one or more bases, one or more salts, and one or more solvents, and the method comprises the steps of: i) calculating pH and/or salt concentration at a particular time t from a user-determined gradient function; and ii) based on the values obtained in step (i), calculating percent acid, percent base, percent salt and percent solvent in the liquid mixture at time t. A liquid chromatography system incorporating such method is also provided.

Abstract: Described are a method and system for diluting a sample in a liquid chromatography system. A sample flowing at a first flow rate is combined for a predetermined time with a diluent flowing at a second flow rate to generate a volume of diluted sample. The diluted sample has a dilution ratio determined according to the two flow rates. A portion of the volume is loaded into a sample loop of an injection valve and subsequently injected into a mobile phase flowing to a chromatography column. The method eliminates the need to have a technician available to perform dilutions or to transfer the sample to a remote location for dilution. Advantageously, manufacturing or processing downtime to perform the dilution is not required and the amount of sample flowing to waste is reduced.

Abstract: Described is a method of transferring a chromatographic method between liquid chromatography (LC) systems and a sample for performing the method. The method is based on a determination of an isoretention temperature at which two solutes co-elute. The method enables separations to be performed using different LC systems with reproducible and equivalent results. For example, the method allows for a chromatography method developed for HPLC to be readily transferred to a UPLC system and for a chromatography method developed for a UPLC system to be more readily transferred to a HPLC system. The method addresses LC systems having column ovens of different design in which the internal column temperatures are not equal although the operating temperatures of the column ovens may be accurately controlled to equal values. The retention behavior and resolution of different LC systems is caused to be substantially the same so that equivalent separation results are obtained.

Abstract: Described is a method of transferring a chromatographic method between liquid chromatography (LC) systems and a sample for performing the method. The method is based on a determination of an isoretention temperature at which two solutes co-elute. The method enables separations to be performed using different LC systems with reproducible and equivalent results. For example, the method allows for a chromatography method developed for HPLC to be readily transferred to a UPLC system and for a chromatography method developed for a UPLC system to be more readily transferred to a HPLC system. The method addresses LC systems having column ovens of different design in which the internal column temperatures are not equal although the operating temperatures of the column ovens may be accurately controlled to equal values. The retention behavior and resolution of different LC systems is caused to be substantially the same so that equivalent separation results are obtained.

Abstract: Described is a method of transferring a chromatographic method between liquid chromatography (LC) systems. The method is based on a determination of an isoretention temperature at which two solutes co-elute. The method enables separations to be performed using different LC systems with reproducible and equivalent results. For example, the method allows for a chromatography method developed for HPLC to be more readily transferred to a UPLC system and for a chromatography method developed for a UPLC system to be more readily transferred to a HPLC system. The method addresses LC systems having column ovens of different design in which the internal column temperatures are not equal although the operating temperatures of the column ovens may be accurately controlled to equal values. The retention behavior and resolution of different LC systems is caused to be substantially the same so that equivalent separation results are obtained.

Abstract: A method for controlling fluid flowing through a chromatographic system includes determining a fluidic parameter related to density at a first fluidic location in the chromatographic system; and in response to the determined fluidic parameter, modifying a volumetric flow rate or a pressure at a second fluidic location in the chromatographic system to produce a selected mass flow rate of the fluid.

Abstract: Techniques for use with dried sample portions include a device having sample areas, identification areas and detachable portions. Each sample area includes one of the dried sample portions of the sample. Each identification area includes information stored therein which identifies the sample from which the dried sample portions stored on the sample areas of the device are obtained. Each detachable portion includes one of the sample areas and includes one of the identification areas. Also described is a method for processing dried sample portions of a sample. A card is received that includes a plurality of detachable portions. Each detachable portion includes a sample area with a dried sample portion and an identification area including information that identifies the sample. A first detachable portion is detached to process a dried sample portion included in the first detachable portion.

Abstract: Described are methods in which the retention times of a chromatographic column are adjusted through the control of the temperature of a mobile phase at the inlet to the chromatographic column. The temperature of the mobile phase at the inlet is different from the temperature of the chromatographic column. Adjustment of the temperature of the mobile phase at the inlet can be used as part of a method to transfer a chromatographic method from one liquid chromatography system to another liquid chromatography system. The method can alternatively be adapted for trapping a sample at the head of a chromatographic column to reduce the amount of band broadening of the sample from the sample injector of a liquid chromatography system. A gradient elution can then be performed to cause the concentrated volume of the analyte in the sample to elute in a tight band, resulting in improved measurement sensitivity.

Abstract: Disclosed is a chromatographic system and method which includes a passive pre-heater assembly. In the inventive system and method a fluid mixture is supplied from an injector to the pre-heater assembly and then to a chromatographic column having an active heating source. The pre-heater assembly includes a convoluted tube with first and second ends and a fluid passage extending centrally therebetween, first and second end fittings attached respectively to the first and second ends of the convoluted tube, and a thermally conductive film attached to an outer surface of the convoluted tube. The first end fitting is adapted for fluidly connecting the first end of the convoluted tube to the injector and the second end fitting is adapted for fluidly connecting the second end of the convoluted tube to the chromatographic column.

Abstract: Described is a method of transferring a gradient separation method to a liquid chromatography system. A value of a delivered gradient slope for a gradient separation method performed on a first liquid chromatography system is determined based on a value of a programmed gradient slope for the gradient separation method and a predetermined relationship between delivered gradient slope and programmed gradient slope for the first liquid chromatography system.

Abstract: A method of preparing a liquid mixture for use in a liquid chromatography system is provided. The mixture comprises one or more acids, one or more bases, one or more salts, and one or more solvents, and the method comprises the steps of: i) calculating pH and/or salt concentration at a particular time t from a user-determined gradient function; and ii) based on the values obtained in step (i), calculating percent acid, percent base, percent salt and percent solvent in the liquid mixture at time t. A liquid chromatography system incorporating such method is also provided.