Detectors used in liquid chromatography

    A liquid chromatography detector is an instrument used in high performance liquid chromatography (HPLC) to detect components of the mixture being eluded off the chromatography column. All HPLC detectors respond to some chemical property of the analyte. HPLC detectors are capable of determining the identity and concentration of eluding compounds in the mobile phase. Various detectors are used in liquid chromatography to analyze different types of samples having different chemical natures. Specific detectors respond to specific compounds.

    Detectors used in liquid chromatography include: UV detectors, UV/VIS Detectors, diode-array detectors, Refractive Index detectors, LED detectors, variable wavelength detectors, multiple wavelength detectors, connectivity monitors, pH monitors and more.

    Flow cells are important components of detectors used for liquid chromatography. Flow cells are the heart of an efficient HPLC detector. Flow cells should be chosen to match your application. A UV flow cell introduces the sample to the detector. The light energy goes through the flow cell where the solute is absorbed. The absorption is read by the detector and is transmitted to the data station for analysis. Flow cells have different volumes and pathlengths that can be optimized for a particular application.

    Many flow cells have the ability to be connected to fiber optics for remote sensing. This capability is vital in PET isotope work, hazardless environments, and process chromatography, FPLC, as well as applications where the flow cell needs to be temperature controlled.

    An ultraviolet detector is known as a UV detector or a UV/VIS detector. It is a nondestructive detector used for liquid chromatography. It measures the amount of ultraviolet or visible light that is absorbed by compounds of a mixture being eluded off the chromatography column.

    Icon Scientific offers the largest selection of the highest quality, miniaturized German engineered UV/ VIS detectors. Our rugged UV/VIS Detectors have endless applications.

     

    Read More

    Some of the most common applications include nano- HPLC, analytical HPLC, uHPLC, Semi prep, preparative HPLC, process HPLC, and flow reaction chemistry monitoring. In addition, our detector line is used for FPLC at all flow rate ranges. UV/VIS detectors are used in student teaching labs, research labs, quality control labs, quality insurance labs, and process skids. We offer five (5) types of UV/VIS detectors: LED, LED dual wavelength, variable wavelength, multi-wavelength and diode array. UV/VIS detectors are equipped with digital and analog outputs and are available with optional remote sensing with fiber optics. Detectors have touch screens or keypads, analog and digital controls. Most types of our UV/VIS detectors are available in field portable versions with optional battery power. We offer the widest array of light sources available in the marketplace. These sources include: LED, UV LED, deuterium, deuterium & halogen, and pulsed xenon. UV/VIS detectors are available with a large choice of flow cells for nanoliters/minute all the way up to liters/minute. Stainless steel, PEEK and Fiber optic versions are available for most flow cells. Our UV/VIS detectors combine the highest performance, smallest size and unlimited flexibility.

    Icon Scientific introduces ANSER LED detectors. Our LED detectors cover the UV from 240nm to 1050nm using either a single fixed LED or two LEDs using novel rapid switching technology. These detectors can handle a wide range of flow cells covering nano liters to liters/min. flow rates. Our full range of
    flow cells include fiber optic connected flow cells with fiber optics available in custom lengths. These detectors are also available in OEM modules.

    Diode array detectors – Diode-array detection is sometimes called DAD. Diode arrays are used to determine the purity of an analyte or related impurity peak eluding during an HPLC separation. The advantages of using a diode array detector is that it allows for the best wavelength(s) to be selected for actual analysis. The second benefit is that often the peak shape does not reveal that it actually corresponds to two or more components. Therefore, absorbance ratioing at two wavelengths is very helpful in deciding whether the peak represents a single compound or is a composite peak.

    The AZURA DAD 2.1L Is a highly competitive diode array detector which combines high performance with easy handling at an affordable price. A wide range of easily exchangeable cartridge flow cells are available. An optional fiber optics adapter offers the possibility of separating the flow cell from the device and thus provides enhanced security for hazardous, explosive or toxic work processes, as well as protecting the device from leakages at high flow rates.

    The newly developed optical unit with intelligent temperature management ensures maximum sensitivity and minimal baseline drift. This diode array detector comes installed with a deuterium lamp covering wavelengths from 190 to 700 nm. It can be controlled by software or through analog or digital input. You are guaranteed easy maintenance and short downtimes.

    The AZURA DAD 6.1 L is a high-end version of the 2.1 L. It offers outstanding performance coupled with easy handling. The DAD 6.1 L has easy frontal access and improved safety features which enable effortless lamp replacement. State of the art reflection flow cells are available as well as an optional fiber optic adapter. The AZURA DAD 6.1 L features a newly developed optic unit that has Knauer Polka-Dot technology and intelligent temperature management.

    Multi-wavelength detector

    A multi-wavelength detector is a UV detector that can monitor several wavelengths simultaneously. There are two ways to achieve this function. The first is to use a variable wavelength detector design with a fast scanning monochromator. The monochromator slews back and forth capturing data from up to 4 wavelengths. This is the most common form of multi wavelength detectors. The Knauer 50 D utilizes this technology. The alternative way of creating a multi wavelength detector is to use diode array technology. This offers simultaneous wavelength data up to 8 wavelengths. The AZUA MWD 2.1 L multiwavelength detector utilizes this technology.

    Variable-wavelength UV detectors-

    Variable-wavelength UV detectors allow you to set a single wavelength either by touch panel keypad or by analog/digital remote control. ICON offers Knauer AZURA 2.1S UV detector. This is the smallest variable UV detector on the market. The Blue Shadow 40D detector offers high performance in a compact enclosure. The AZURA UVD 2.1 L is designed to be integrated into a stacked HPLC system. Both the Azura 2.1s, the 40D and the 2.1 L offer remote flow cell options by using fiber optics.

    Conductivity/ pH monitor-

    Conductivity monitors are used in FPLC to follow the salt gradients. pH values can be measured which is useful when running a pH gradient. The AZURA CM 2.1 S is a small reliable connectivity monitor which optionally monitors pH values.