Provided herein, among other aspects, are methods and apparatuses for analyzing particles in a sample. In some aspects, the particles can be analytes, cells, nucleic acids, or proteins and contacted with a tag, partitioned into aliquots, detected by a ranking device, and isolated. The methods and apparatuses provided herein may include a microfluidic chip. In some aspects, the methods and apparatuses may be used to quantify rare particles in a sample, such as cancer cells and other rare cells for disease diagnosis, prognosis, or treatment.

Various embodiments include methods and systems to measure and calibrate an optical particle spectrometer for reporting mass concentration. In one embodiment, an optical particle spectrometer is used to measure a concentration of particulate matter in a sampled particle-laden airstream. A particle diverter, in fluid communication with the spectrometer, diverts at least a portion of the particle-laden airstream at predetermined intervals. In one example, a mass filter receives the portion of the particle-laden airstream and filters a fraction of the particles within the airstream that are above a predetermined particle size. A mass sensor measures a mass of the fraction of the particles received from the mass filter or from the particle diverter and uses a calibration communication loop to provide the measured mass to the spectrometer to apply a correction factor to report mass concentration from the optical particle spectrometer. Other methods and systems are disclosed.

A filtering device generally constructed from two panels is disclosed herein. The device may be used for the isolation, concentration, and detection of particles with particular chosen characteristics. A first panel, an etched or molded filter panel, includes an array of V-shaped channels wherein the walls of the V-shaped channels have spacer pads and offset walls that create filtering pores when the filter panel is mated to a flat surface of a second panel. The use of semiconductor processing equipment provides incredible accuracy as well as the ability to construct extremely small features.

To uniformly dilute particulate matter contained in a sample gas, a diluter includes an inflow portion, a mixing portion, a discharge portion, a connection portion, and an introduction portion. The inflow portion allows a sample gas to flow in. The mixing portion has an inner diameter larger than that of the inflow portion, and mixes the sample gas with a dilution gas to generate a diluted sample gas. The discharge portion discharges the diluted sample gas. The connection portion has a first tapered part whose inner diameter increases from a side connected to the inflow portion toward a side connected to the mixing portion. The introduction portion introduces the dilution gas into an internal space from a position downstream of the connection between the first tapered part and the inflow portion.

An environmental sampling chamber for sampling the particulates and substances emitted from a test sample when the surface of the sample is ablated. The sampling chamber avoids the need for clean rooms and other expensive testing apparatus and can be used to test a variety of materials in accordance with standard measurement procedures. Use of the testing chamber and methods assists with safety and risk evaluation in applications such as painting and removal of coatings.

A filter for filtering particulates from a fluid stream includes a filter element with a filter medium and a metallic debris sensor assembly. The metallic debris sensor assembly includes a core and a coil of electrically-conductive wire. The core has a first end, a second end, and an intermediate portion interposed between the first and second ends. The first end is disposed in spaced relationship with the second end such that a measurement area is disposed therebetween. The coil of electrically-conductive wire is wound around the intermediate portion of the core. The core is adapted to generate a magnetic field in the measurement area when an electrical current is passed through the coil. At least a portion of the filter medium of the filter element is disposed within the measurement area. The filter can be incorporated into a wear detection system and used in methods of monitoring.

Systems for detecting aerosolized viral loads in an airspace include a first and, optionally, a second volume of a liquid. The first volume includes particles sampled from the airspace, and the second volume is free of virus particles. A first conductivity probe is immersed in the first liquid, and a second conductivity probe is immersed in the second liquid. An alternating voltage is applied to each of the first and second conductivity probes. The difference between the resulting alternating currents through the first and second conductivity probes is determined, and is used to estimate the viral load in the first volume, and in the airspace.

A water quality management method for performing at least one of a quantitative analysis and a qualitative analysis of fine particles contained in water to be analyzed that includes connecting a filtration device provided with a fine particle capturing membrane for capturing fine particles to a flow pipe through which the water to be analyzed flows, allowing the water to be analyzed to flow from the flow pipe and through the fine particle capturing membrane attached to the filtration device for a predetermined period of time to capture fine particles contained in the water to be analyzed to form a fine particle capturing membrane sample, and performing at least one of a quantitative analysis and a qualitative analysis of the fine particle capturing membrane sample of a target water flow period at an arbitrary timing.

A sampling device is constructed having an airflow path from a size-selective inlet to a device outlet, without using any tubing. The size-selective inlet includes at least one of an impactor, a filter, a cyclone, and an inhalable inlet. The device includes a sampling assembly configured to be removably coupled directly to a sampling device housing (e.g., without using tubing), and an airflow assembly that may be constructed without using tubing.

A flow-through sampling apparatus for sampling a bulk solid mixture includes a main body forming an opening. A screen is located in the opening and forms a plurality of sample zones within the main body. The apparatus further includes a first slide door that is movable above the screen so as to close one side of the opening. Further, the apparatus includes a second slide door that is movable below the screen so as to close the other side of the opening.