Help with High Performance Liquid Chromatographs (HPLC) specifications:
Instrument Type
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| Instrument Type: | |||
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| Portable Instrument | Has handles/case/wheels etc. to make easy to move, not necessarily held in hand to use. | ||
| Fixtured or Permanent | Mounted or fixtured in place for long-running use. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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Environment
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| Operating Temperature: | This is the full-required range of ambient operating temperature. | ||
| Search Logic: | User may specify either, both, or neither of the limits in a "From - To" range; when both are specified, matching products will cover entire range. Products returned as matches will meet all specified criteria. | ||
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Analysis Method
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| Analysis Method: | |||
| Your choices are... | |||
| Analytical Analysis | Analytical HPLC is used to obtain information about the sample compound. | ||
| Preparative Scale Analysis | Preparative HPLC refers to the process of isolation and purification of compounds. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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Detection Method
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| Detection Method | |||
| Your choices are... | |||
| Ultraviolet / Visible Light Detector | UV detectors are the most commonly used detector. They measure the ability of a sample to absorb light. This can be accomplished at one or several wavelengths. A variable wavelength UV detector, capable of monitoring from 190 to 460-600 nm will be found suitable for the detection of the majority of samples. | ||
| Refractive Index Detector | The detection principle involves measuring of the change in refractive index of the column effluent passing through the flow-cell. The greater the RI difference between sample and mobile phase, the larger the imbalance will become. | ||
| Fluorescence Detector | Very sensitive, but very selective. It is possible to detect even a presence of a single analyte molecule in the flow-cell. Fluorescence occurs when compounds having specific functional groups are excited by shorter wavelength energy and emit higher wavelength radiation. | ||
| Radiochemical Detector | Radiochemical detection involves the use of radio labeled material, usually Tritium or Carbon-14. It operates by detection of fluorescence associated with beta-particle ionization, and it is most popular in metabolite research. | ||
| Electrochemical Detector | Very sensitive but very selective. It is based on the measurements of the current resulting from an oxidation/reduction reaction of the analyte at a suitable electrode. The level of the current is directly proportional to the analyte concentration. | ||
| Light Scattering Detector | Evaporative light scattering detectors involve nebulization of the column effluent to an aerosol, followed by solvent vaporization to produce small solute droplets, and then these droplets are detected in the light scattering cell. | ||
| Mass Spectroscopy Detector | The sample compound is ionized, it is passed through a mass analyzer, and the ion current is detected. | ||
| Nuclear Magnetic Resonance Detector | Certain nuclei with odd numbered masses spin about an axis in a random fashion. However, when placed between poles of a strong magnet, the spins are aligned either parallel or anti-parallel to the magnetic field. The nuclei are then irradiated with electromagnetic radiation that is absorbed and places the parallel nuclei into a higher energy state; consequently, they are now in "resonance" with the radiation. Each atom will produce a different spectra depending on their location and adjacent molecules, or elements in the compound. | ||
| Other | Other unlisted or proprietary detector type. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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Injection Method
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| Injection Method: | Sample introduction can be accomplished in various ways. The simplest method is to use an injection valve. In more sophisticated LC systems, automatic sampling devices are incorporated where the sample introduction is done with the help of autosamplers and microprocessors. | ||
| Your choices are... | |||
| Valve Injection | The sample is introduced via a valve. | ||
| Auto-sampler Injection | The sample is introduced via an autosampler. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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Pump Specifications
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| Pump Operating Method: | High-pressure pumps are needed to force solvents through packed stationary phase beds. Flow rate stability is another important feature that distinguishes pumps. | ||
| Your choices are... | |||
| Isocratic | Compounds are eluted using constant mobile phase composition. Each compound migrates at a different rate resulting in faster or slower elution rate. | ||
| Gradient | Increasing the strength of the organic solvent elutes different compounds. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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| Flow Control? | Flow control is a very desirable feature when automation or electronically controlled gradients are to be run. It is an undesirable feature when isocratic methods are to be used. The degree of control will vary with pump expense. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Flow Rate | The flow rate that the pump operates at. Flow rate stability is an important pump feature that distinguishes pumps. | ||
| Search Logic: | User may specify either, both, or neither of the limits in a "From - To" range; when both are specified, matching products will cover entire range. Products returned as matches will meet all specified criteria. | ||
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| Maximum Pump Pressure | The maximum pressure that the chromatograph can operate at. | ||
| Search Logic: | All matching products will have a value greater than or equal to the specified value. | ||
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| Pump Accuracy | The pump accuracy also refers to the flow rate accuracy. | ||
| Search Logic: | All matching products will have a value less than or equal to the specified value. | ||
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User Interface Options
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| Local Interface: | |||
| Your choices are... | |||
| Analog Front Panel | The panel has analog user inputs such as potentiometers, dials, switches, for adjustment of output, ranges, etc. | ||
| Digital Front Panel | The panel uses digital keypads or menus for programming. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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| Computer Interface? | Can be controlled or monitored remotely with a computer via interface. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Computer Interface Options: | |||
| Your choices are... | |||
| Serial Interface | A port, or interface, that can be used for serial communication, in which only one bit is transferred at a time. Examples include RS232, RS422, RS485, and USB. | ||
| Parallel Interface | A channel capable of transferring more than one bit at a simultaneously. Examples include PC printer port, Centronics. | ||
| Other Computer Interface | Modem, transmitter, TTL, etc. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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| Application Software Included? | For control or for monitoring chromatographic process. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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Display Options
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| Display Options: | |||
| Your choices are... | |||
| Analog Meter | Data is displayed with an analog meter or simple visual indicator. | ||
| Digital Readout | Device uses numerical or application specific display. | ||
| Video Display | The data is presented in video form via CRT, LCD, or other multi-line forms. | ||
| None | No integral display. Output is read and displayed remotely. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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Additional Output Options
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| Additional Output Options: | |||
| Your choices are... | |||
| Analog Voltage | Any analog voltage output. Output voltage is a simple (usually linear) function of the measurement. | ||
| Frequency / Modulated Frequency Pulse | Frequency or modulated frequency output (Ex. sine wave, pulse train, AM, FM). | ||
| Analog Current | 4-20mA, or any other analog current output. Often called a transmitter. A current is imposed on the output circuit proportional to the measurement. Feedback is used to provide the appropriate current regardless of line noise, impedance, etc. Useful when sending signals long distances. | ||
| Switch or Relay Contact | The ''output'' is a change in state of a switch or an alarm. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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General Features and Functionality
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| Programmable? | Detector has programming features. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Built in Chromatograph? | Detector has a built in recorder for chromatograph outputs. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Self-Calibration? | The chromatograph is capable of calibrating itself. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Extreme Environment? | The chromatograph is configured to operate in extreme environments, temperature, humidity, dust, etc. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Self-Test Diagnostics? | The chromatograph can perform self-test diagnostics to assess any errors. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Data Storage Options? | Detector has data storage options. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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