SubscribeDipTip™ is a miniature transmission probe for microliter spectroscopic sampling.
DipTip's tip diameter is only 1.5 mm -- the size of a 17-gauge needle! It will fit into all micro centrifuge tubes on the market and is a very useful tool for measuring protein and DNA samples. The diminutive dipping probe can also be used for a dissolution system.
Thanks to WPI's proprietary optical design, DipTip is not only four to five times smaller in diameter than any other product on the market, but also costs 50% less! Together with our fiber optic-based spectrophotometers (TIDAS II) or spectrometer modules (TIDAS I) or CCD (SPECTRAUSB) and light sources (D2H, D2LiteTM, and FO-6000TM) microliter samples can be analyzed very cost effectively. See later in the article for more information on these WPI products.
To exemplify the performance of the DipTip, Bovine Serum Albumin (BSA) dissolved in a phosphate buffer BSA has been analyzed with a TIDAS II. Absorbance spectra and a calibration curve are shown. Each spectra has been obtained from 50 to 60 µl samples stored in 0.1 mL centrifuge vials.
| DIP-UV | DIP-NIR | DIP-UV-SR | |
|---|---|---|---|
| Tip diameter | 1.5mm | 1.5 mm | 1.5mm |
| Light pathlength | 2, 5, 10mm | 2, 5, 10mm | 2, 5, 10mm |
| Wavelength Range (nm) | 230-1000 | 350-1000 | 200-1000 |
| Sample Volume Required | 20-50 µL | 20-50 µL | 20-50 µL |
| Distance from tip to upper edge of sample window | 7 mm | 7 mm | 7 mm |
| Total length (including handle) | 18 cm | 18 cm | 18 cm |
| Fiber length (from connector to tip) | 1.5 m | 1.5 m | 1.5 m |
| Fiber Optic Connectors | SMA 905 | SMA 905 | SMA 905 |
Launch fibers (2) NA = 0.22 | 400 µm | 400 µm | 400 µm |
| Return Fiber (1) NA = 0.22 | 400 µm | 400 µm | 400 µm |
WPI offers complete preconfigured systems for a variety of applications from protein analysis to flow-through colorimetric detection in the UV-VIS-NIR spectral region. WPI's scientists ensure everything works together and offers the best results. They have tested each preconfigured system over many hours in research labs.
TIDAS II is the first high-end spectrophotometer specifically designed for cuvette-based and fiber optic sampling. TIDAS II outperforms conventional bench-based spectrophometers with its speed and ultra low noise. Unlike other spectrometers, the separate positioning of the lamps in the TIDAS II prevents the deuterium lamp from being penetrated by rays from the halogen lamp. The life span of the deuterium lamp is thus dramatically extended.
Light penetrates the sample chamber through optical fibers. The optical design of the TIDAS II is based on fiber optics, resulting in a very efficient light throughput and an exceptional signal to noise ratio. This allows external probes, such as our LWCC, SpectroPipetter™ or DipTip™ to be connected directly to the TIDAS II without the use of any adapters. Optionally, the instrument can be equipped with a multiple cuvette holder, a temperature control and a magnetic stirrer.
TIDAS I is the first high-end spectrometer module designed for fiber optic based sampling techniques. Using suitable light sources and sample cells, spectral detection in the wavelength range of 195 to 730 nm can be performed at noise levels as low as 0.8 mAU. TIDAS I outperforms conventional bench-based spectrophotometers and CCD-based spectrometer modules, when it comes to high precision fiber optic sampling.
Using fiber-optic based sample cells and light sources, high-end detection systems with exceptional sensitivity and noise performance can be easily assembled. Using our liquid waveguide capillary cells (LWCC), absorbance based detection system with effective pathlengths as long as 500 cm and noise levels as low as 0.1 mAU can be achieved at reasonable cost.
Miniature Spectrometers
WPI offers now its SpectraUSB miniature spectrometers optimized for absorbance, fluorescence and NIR applications. The SpectraUSBs are miniature spectrometers, which plug directly into the USB port of any desktop or notebook PC. With the SpectraUSB, getting started is as easy as installing WPI's SpectraWare™ software package and connecting the tiny spectrometer to the USB port of the computer.
Other features make operating the spectrometer equally hassle-free. The spectrometer does not require an external power supply; it simply draws its power from the computer. The SpectraUSB spectrometer is pre-set to a 200-850 nm wavelength range and comes with a UV2-enhanced UV detector upgrade, a multi-bandpass order-sorting detector coating, along with a 25 µm entrance slit installed for an optical resolution to 1.5 nm (FWHM).
WPI offers different gratings for the spectrometer, which define its wavelength range. The resolution of the spectrometer is determined by its slit-width (SLIT-xxx). The miniature spectrometers can be equipped with a number of detector upgrades. A collection lens (L2) can be placed in front of the detector array to increase the spectrometers light collection efficiency and reduce stray light.
This is especially useful when using large core diameter fibers in low light-level applications. A CCD array with 2048 pixels is used as this detector. UV2, available at WPI, is a detector upgrade, which is required for measuring at wavelength below 350 nm. Multi-bandpass order sorting filters are available to avoid second order effects in the spectrometer modules (OFLV).
SpectraUSB-NIR is preset to a 350-900 nm range and is equipped with a 25 µm slit. In addition, we offer snap-on, direct attach accessories specifically designed for these spectrometers. USBVIS and USBUV are light source/cuvette holder combos for absorbance measurements in the 390-950 nm for VIS/NIR range and 200-950 nm UV/VIS/NIR range respectively.
SpectraUSB-M2 is a basic spectrometer, equipped with a grating or your choice. Detector upgrades (Slit, L2, UV2 and OFLV) can be selected when ordering the instrument. If an application requires a specific wavelength range, resolution or sensitivity, contact WPI for customisation.
SpectraUSB-DBL is a dual channel spectrometer, pre-set to a 200-850 nm wavelength range and comes with a UV2- enhanced UV detector upgrade, a multi-bandpass order-sorting detector coating, along with a 25 µm entrance slit installed for an optical resolution to 1.5 nm (FWHM).
Spectra-HR is a high-resolution version of the SpectraUSB miniature spectrometer series that WPI offers. Its key advantage is the excellent optical resolution of 0.035 nm (FWHM), usually only found in spectrometers with a far higher price tag. The SpectraHR is especially suited for applications, such as wavelength characterization of lasers and LEDs, monitoring of gases and monochromatic light sources, and determination of elemental atomic emission lines.
The SpectraHR can be equipped with all upgrades available for the SpectraUSB-M2; contact WPI for customization. For wide wavelength range applications, WPI offers now high resolution spectrometer (SpectraHR-CG) with a new proprietary composite grating, a 5 µm slit, UV2 upgrade and order-sorting filter to provide a 200-1100nm wavelength range and 1.0nm optical resolution in one spectrometer.
SPECTRAUSB-FLG is a pre-configured spectrometer for fluorescence applications, equipped with a L2 lens and a 200 µm slit. Integrated into this detector is a time-gated mode that delays the start of spectral data acquisition by 5-500 microseconds after the excitation source is turned on. Using a pulsed light source, the detector sees in this mode the sample when the light is switched off.
However, in order to use the gated phosphorescence mode, the fluorophore must have a long fluorescence lifetime. Those working with lanthanides and phosphorescent materials will find the gated phosphorescence mode particularly useful. To further improve the efficiency of the detector, the standard mirrors of the optical bench were replaced by Ag-coated mirrors. This improved the sensitivity of the detector by over 20%.
Multichannel Detector
Spectra-MCx is a multi-channel spectrometer that can be configured with one master and two to seven slave channels. These channels are installed inside a rack-mountable enclosure. Each channel can be custom-configured with all the upgrade options available for the SpectraUSB series (grating, slit, UV2, L2, OFLV).
The multi-channel spectrometer is connected to a computer via a USB interface module (502117, order separately). The SPECTRA-MC system is particularly useful for applications such as small volume dissolution testing, when combined with WPI's miniature dipping probes (DipTip) and FO-6000 light source.
Light Sources
WPI also offers a variety of light sources including but not limited to D2H, D2LiteTM, and FO-6000TM. The D2H is a combined deuterium and halogen light source for UV/VIS and NIR applications and is ideally suited to work with WPI's spectrometer modules and sample cells. For deep UV applications (190 nm), the D2H-2 should be used.
D2LiteTM is a new miniature deuterium light source has been developed for portable and low-power spectroscopy applications. Its advantage lies in fast and convenient single measurement cycles and its short warming up time.
The FO-6000TM is a new miniature tungsten light source that has been developed for high precision portable and low-power spectroscopy applications. It was developed to overcome the problem with tungsten light bulbs and their inherent low light output at wavelengths below 430nm. Its advantage lies in its high light power output, its effective color temperature of 6000K and its exceptionally low drift below 0.5 mAU/h. The inherent low noise of the FO-6000 makes it particularly suitable for low-noise detection systems.
The FO-6000FILT inline filter holder directly attaches to the FO-6000 light source. This allows a virtual light loss free insertion of optical filters with outer diameters from 8 to 25.4 mm and thickness ranging from 2 to 10 mm into the light path of the FO-6000. With this filter holder and an optical filter, a highly stable monochromatic light source can be assembled. These light sources offer a wide assortment of field applications in environmental and life science as well as analytical chemistry.
| D2LITE | D2H / D2H-2 | FO-6000 | |
|---|---|---|---|
| Application | UV/VIS/NIR | UV/VIS/NIR | VIS/NIR |
| Spectral Range | 200 -- 1700 nm | 215/190 -- 1700 nm | 380 -- 1700 nm |
| Deuterium lamp life | 1000 hr | 1000 hr | N/A |
| Tungsten/Halogen lamp life | 2000 hr | 1000 hr | 3000* hr |
| Stability | <1 mAU/h | <0.5 mAU/h | <0.5 mAU/h |
| Power Consumption | 6 W | 100 W | 6 W |
| Power requirements | 12Vdc/0.5A | 110/240V, 50-60Hz | 1A 12VDC/1A |
| Shutter/TTL trigger | Yes | Yes | Yes |
| Max. Fiber Output | 1000 mm | 1000 mm | 1000 mm |
| Connections | SMA | SMA | SMA |
| Shipping Weight | 1.0 lb (0.4 kg) | 13.2 lb (6 kg) | 1.3 lb (0.6 kg) |
| Dimensions (W/H/L) | 2.7 x 2.6 x 6.7 | 5.3 x 5.9 x 12.6 | 4.8 x 2.8 x 7.5 |
| (7 x 6.5 x 17) | (13.5 x 15 x 32) | (12 x 7 x 19) | |
*Lamp life is dependent upon internal power settings. | |||