Help with GC Detectors specifications:
Instrument Type
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| Instrument Type | |||
| Your choices are... | |||
| 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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Detection Method
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| Detection Method: | |||
| Your choices are... | |||
| Thermal Conductivity Detector | A TCD consists of an electrically-heated wire or thermistor. The temperature of the sensing element depends on the thermal conductivity of the gas flowing around it. Changes in thermal conductivity, such as when organic molecules displace some of the carrier gas, cause a temperature to rise in the element, which is sensed as a change in resistance. | ||
| Flame Ionization Detector | An FID consists of a hydrogen/air flame and a collector plate. The effluent from the GC column passes through the flame, which breaks down organic molecules and produces ions. The ions are collected on a biased electrode and produce an electric signal. | ||
| Atomic Emission Detector | The AED simultaneously determines the atomic emissions of many of the elements in analytes that elute from the GC capillary column. As eluants come off the capillary column they are fed into a microwave powered plasma (or discharge) cavity where the components are destroyed and their atoms are excited by the energy of the plasma. The light that is emitted by the excited particles is separated into individual lines via a photodiode array. | ||
| Electron Capture Detector | The ECD uses a radioactive Beta emitter (electrons) to ionize some of the carrier gas and produce a current between a biased pair of electrodes. When organic molecules contain electronegative functional groups, such as halogens, phosphorous, and nitro groups pass by the detector, they capture some of the electrons and reduce the current measured between the electrodes. | ||
| Photoionization Detector | The PID uses ultraviolet light as a means of ionizing an analyte exiting from a GC column. Electrodes collect the ions produced by this process. The current generated is therefore a measure of the analyte concentration. | ||
| Flame Photometric Detector | This device uses the chemiluminescent reactions of phosphorous containing compounds in a hydrogen/air flame as a source of analytical information that is relatively specific for substances containing these atoms. | ||
| Chemiluminescence Spectroscopy | Chemiluminescence uses quantitative measurements of the optical emission from excited chemical species to determine analyte concentration. Usually the emission is measured from energized molecules rather than excited atoms. The bands of light determined by this technique emanate from molecular emissions and are therefore broader and more complex than bands originating from atomic spectra. | ||
| Nitrogen Phosphorous Detector | Compounds are burned in plasma surrounding a rubidium bead supplied with hydrogen and air. Nitrogen and phosphorous containing compounds produce ions that are attracted to the collector. The number of ions hitting the collector is measured and a signal is generated. | ||
| Other | Argon discharge detector, discharge ionization detector, electrolytic conductivity detector, 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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Detector Specs
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| Detection Limit or Sensitivity: | The limit to which the detector can detect the solutes. | ||
| Search Logic: | All matching products will have a value less than or equal to the specified value. | ||
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| Dynamic Range: | This is the range where the peak area is directly proportional to the solute amount (e.g., doubling the solute amount results in a doubling of peak area). This allows for the quantification of unknown samples using a multi-point calibration curve. | ||
| Search Logic: | All matching products will have a value less than or equal to the specified value. | ||
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| Temperature Range: | The temperature range within which the detector operates. | ||
| 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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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, USB etc. | ||
| Parallel Interface | A channel capable of transferring more than one bit at a simultaneously. Examples include PC Printer Port, Centronics etc. | ||
| Other | 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 | Frequency or modulated frequency output (Ex. sine wave, pulse train, AM, FM). | ||
| Analog Current | 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 over long distances. | ||
| Switch or Relay Contact | The output is a switch or 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 Chromatogram? | 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 detector 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 detector 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 detector 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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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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