The present invention provides a particle enhanced agglutination immunoassay including the steps of: mixing a sample solution containing an analyte with a solution containing insoluble carrier particles carrying a binding partner or binding partners for the analyte to prepare a mixed solution; determining a variation (i) in intensity of light scattered from the mixed solution based on a difference in intensity of scattered light between first and second time points; determining a variation (ii) in absorbance of the mixed solution based on a difference in absorbance between third and fourth time points; and correlating the determined variation (i) in intensity of scattered light and the determined variation (ii) in absorbance with an amount of the analyte present in the sample using a calibration curve plotted based on the variation in intensity of scattered light and a calibration curve plotted based on the variation in absorbance. The present invention employs measurements of the intensity of scattered light and the absorbance in combination for a single assay, and thus provides a particle enhanced agglutination immunoassay which achieves higher sensitivity and a wider dynamic range than conventional assays.

A settling rate of at least one foulant in oil-based fluids may be determining a settling rate of an oil-based fluid by stirring the fluid during a turbidimetric flocculation titration, which includes solvent dosing and obtaining transmittance measurements of the oil-based fluid. The method may further include stopping the solvent dosing at the onset of flocculation of the foulant(s), stopping the stirring when at least two or more transmittance measurements are substantially similar, and measuring the transmittance of the oil-based fluid to determine a settling rate of the foulant(s). The settling rate may be proportional to an increase in transmittance or decrease in absorbance after the stirring has stopped.

A settling rate of at least one foulant in oil-based fluids may be determining a settling rate of an oil-based fluid by stirring the fluid during a turbidimetric flocculation titration, which includes solvent dosing and obtaining transmittance measurements of the oil-based fluid. The method may further include stopping the solvent dosing at the onset of flocculation of the foulant(s), stopping the stirring when at least two or more transmittance measurements are substantially similar, and measuring the transmittance of the oil-based fluid to determine a settling rate of the foulant(s). The settling rate may be proportional to an increase in transmittance or decrease in absorbance after the stirring has stopped.

The invention relates to a method for analysing a blend of two or more hydrocarbon feed streams such as crude oils. These crude oils are blended in a facility such as a refinery. The method assesses the compatibility of a hydrocarbon feed in a blend to calculate the blend stability such that organic deposition is minimised The method uses all of a plurality of hydrocarbon feeds to be blended for analysis. The method either selects a neat hydrocarbon feed, from a plurality of the hydrocarbon feeds included in a blend, as a titrant, wherein the or each other hydrocarbon in the hydrocarbon feed are used to make a pseudo-blend and titrating the pseudo-blend with said selected neat hydrocarbon feed for a plurality of different blend ratios. Alternatively the method involves preparing a reference hydrocarbon and making a blend from the plurality of hydrocarbon feeds and titrating the blend with the reference hydrocarbon. Measurements associated with the change in characteristics of the titrated blend are made and data recorded. The method then calculates, using said data, the stability of the blend.

The invention relates to a method for analysing a blend of two or more hydrocarbon feed streams such as crude oils. These crude oils are blended in a facility such as a refinery. The method assesses the compatibility of a hydrocarbon feed in a blend to calculate the blend stability such that organic deposition is minimised The method uses all of a plurality of hydrocarbon feeds to be blended for analysis. The method either selects a neat hydrocarbon feed, from a plurality of the hydrocarbon feeds included in a blend, as a titrant, wherein the or each other hydrocarbon in the hydrocarbon feed are used to make a pseudo-blend and titrating the pseudo-blend with said selected neat hydrocarbon feed for a plurality of different blend ratios. Alternatively the method involves preparing a reference hydrocarbon and making a blend from the plurality of hydrocarbon feeds and titrating the blend with the reference hydrocarbon. Measurements associated with the change in characteristics of the titrated blend are made and data recorded. The method then calculates, using said data, the stability of the blend.

The invention relates to a method for analyzing a blend of two or more hydrocarbon feed streams such as crude oils. These crude oils are blended in a facility such as a refinery. The method assesses the compatibility of a hydrocarbon feed in a blend to calculate the blend stability such that organic deposition is minimized. The method uses all of a plurality of hydrocarbon feeds to be blended for analysis. The method either selects a neat hydrocarbon feed, from a plurality of the hydrocarbon feeds included in a blend, as a titrant, wherein the or each other hydrocarbon in the hydrocarbon feed are used to make a pseudo-blend and titrating the pseudo-blend with said selected neat hydrocarbon feed for a plurality of different blend ratios. Alternatively the method involves preparing a reference hydrocarbon and making a blend from the plurality of hydrocarbon feeds and titrating the blend with the reference hydrocarbon. Measurements associated with the change in characteristics of the titrated blend are made and data recorded. The method then calculates, using said data, the stability of the blend.

The invention relates to a method for analyzing a blend of two or more hydrocarbon feed streams such as crude oils. These crude oils are blended in a facility such as a refinery. The method assesses the compatibility of a hydrocarbon feed in a blend to calculate the blend stability such that organic deposition is minimized. The method uses all of a plurality of hydrocarbon feeds to be blended for analysis. The method either selects a neat hydrocarbon feed, from a plurality of the hydrocarbon feeds included in a blend, as a titrant, wherein the or each other hydrocarbon in the hydrocarbon feed are used to make a pseudo-blend and titrating the pseudo-blend with said selected neat hydrocarbon feed for a plurality of different blend ratios. Alternatively the method involves preparing a reference hydrocarbon and making a blend from the plurality of hydrocarbon feeds and titrating the blend with the reference hydrocarbon. Measurements associated with the change in characteristics of the titrated blend are made and data recorded. The method then calculates, using said data, the stability of the blend.

An instrument and a method for measuring the characteristics of particles in a sample. The instrument comprises a light source operable to provide a light beam and defining an illumination axis; a sample cell placed on the illumination axis; a scattered light detector positioned to receive scattered light along a detection path from a sample in the sample cell, the scattered light produced by the interaction of the light beam with the sample; and a filter changer positioned between the sample cell and the scattered light detector. The filter changer comprises at least one optical filter and an actuator. The actuator is operable to move each of the at least one optical filter between a first position in which the detection path does not pass through the optical filter, and a second position in which the detection path passes through the optical filter.

An instrument and a method for measuring the characteristics of particles in a sample. The instrument comprises a light source operable to provide a light beam and defining an illumination axis; a sample cell placed on the illumination axis; a scattered light detector positioned to receive scattered light along a detection path from a sample in the sample cell, the scattered light produced by the interaction of the light beam with the sample; and a filter changer positioned between the sample cell and the scattered light detector. The filter changer comprises at least one optical filter and an actuator. The actuator is operable to move each of the at least one optical filter between a first position in which the detection path does not pass through the optical filter, and a second position in which the detection path passes through the optical filter.

A system for processing samples from a body of fluid. The system includes one or more sample bottles for acquiring a sample from the body of fluid. Each sample bottle initially retains a pre-filling fluid. Each sample bottle includes a fluidic inlet port and a bottle outlet port. Each sample bottle has an inlet check valve coupled to the fluidic inlet port, the inlet check valve configured to allow fluid from the body of fluid into a sample bottle via the fluidic inlet port when the pressure difference between the body of fluid and fluid within the sample bottle reaches a threshold. The system further includes at least one pump, the bottle outlet port of each sample bottle selectively coupled to the at least one pump via a different control valve. The at least one pump is configured, in a first configuration, to remove prefilling fluid from each selected sample bottle such that, for each selected sample bottle, the pressure difference threshold is reached and a sample from the body of fluid is acquired.