Colloidal analytics puts highest demands to the experimental equipment. For this reason, we use only high-end instruments from leading manufacturers. The highest performance, representing the state of the art and beyond, is guaranteed.
Beckman Coulter's Optima XL-A/XL-I Analytical Ultracentrifuge represents the highest performance available to date. At an angular velocity of 60,000 rpm, a centrifugal field equivalent to 260,000 fold of the Earth's gravity arises. The instrument is equipped with two independent optical systems, Rayleigh interference optics and Absorbance optics covering a range from 190 to 800 nm. Radial resolution is 0.01 mm, wavelength resolution is 1 nm.
The sample cells are applicable to any solvents, including acids, bases and organic solvents. This is due to the fact that the centerpieces are
made of titanium. Such cells are not available from Beckman Coulter, but exclusively from Nanolytics Instruments.
In order to adjust the respective signal intensities we use centerpieces with four different optical path lengths: 1.5 mm, 3 mm, 12 mm, 20 mm (Fig. 2).
The cell windows are made of sapphire.
We use Nanolytics Instruments' cell alignment tool for precise alignment of the cells within the rotor.
Nanolytics routinely uses Nanolytics Instruments' „AIDA“ Ultracentrifuge in addition to the Optima XL-I.
AIDA detects a more than 5fold number of fringes, thus improving the signal/noise ratio and enhancing resolution (Fig. 3).
As a further option higher orders of refraction can be detected.
The sensitive interference detection of the AIDA centrifuge extends the tractable concentration range of protein solutions to ca. 0.03-80 mg/mL, allowing to derive sedimentation coefficient distributions. With BSA solutions we achieved even successful results within a range of 0.01-150 mg/ml.
Also for absorbance detection, Nanolytics features ahead state-of-the-art equipment. Nanolytics Instruments' Multiwavelength Absorbance detector yields 2048 wavelengths at high resolution and reproducibility, providing three orders of magnitude (Fig. 4) more data than a classical XLA detector. The high content of information allows for deconvolution of compelx systems.
Static and Dynamic Light Scattering
The Brookhaven BI-200SM is a
multiangle goniometer for making static and dynamic light scattering measurements. The useful angular range is 10° to 155°, depending
on the quality of the sample. Motor driven, steps as small as 0.01° allow for extremely precise determination of structure functions.
The sample cell chamber can be temperature controlled (+5 to +80°C).
For detection, we use a high-quality photon multiplier tube with low dark counts and low afterpulsing. Detector optics include selectable pinholes. Furthermore, an Avalanche Photodiode Array BI-APD by Brookhaven Instruments is available; this detection system is optimized for the detection of red photons.
A high performance filtration system guarantees for an absolutely clean index-matching liquid.
For dynamic measurements, we use the Brookhaven BI-9000AT digital photon correlator. The maximum count rate is 40 Mcps. With up to 522 user-selectable channels, 16-bit multiplications, a delay time range from 100 ns to 1 310 s, with linear and nonlinear channel spacing, the BI-9000AT is the most flexible correlator available.
The Light Scattering setup is equipped with two light sources by Toptica Photonics; 70 mW are emitted at wavelengths of 406 and 641 nm, respectively.
Our Flow-Field-flow fractionation is an instrument by postnova analytics, series HRFFF 10.000. The modular construction, especially the novel, patented separation channel, permits easy handling, especially the changing of membranes and spacers, following the requirements of the system in question, within several minutes. Samples are injected onto the channel in dilute solution; concentration occurs on-channel (focussing). The separation range is given to reach from 1 nm to 100 µm, or 103 to 1012, respectively.
Size exclusion chromatography - SEC-MALLS
Our SEC is equipped with degaser and analytical pumps by Postnova. Columns are selected according to the individuals demands of the system in question. Two detectors - refractive index and light scattering - are used for characterization of the eluted fractions.
Postnova's refractive index detector combines high sensitivity with excellent baseline stability. Refractive numbers from 1,00 to 1,75 are accessible, baseline noise is on a level of 2.5 * 10-9 refractive index numbers. This outstanding performance is mainly dedicated to the sophisticated temperature control, allowing measurements between 30 and 50°C. The volume of the cuvette is 9 µl.
The multi-angle laser light scattering device PN 3070 by Postnova is actually Brookhaven Instruments' product BI-MwA. Light scattering is measured at seven angles in high precision in a wide dynamic range. The internal PEEK cell is 100 µl large, the scattering volume is 20 nl. Scattering is induced with a 635 nm, 35 mW laser. Providing careful calibration, molecular masses in a range von 1000 to 109 g/mole are accessible with an error as small as 1%.
Electron microscopy is provided by our cooperation partner, who not only contributes first class equipment,
but is also a recognized expert in TEM preparation and examination techniques. Thus, you are supplied with exceptional instrumental and human resources.
The Philips CM 300 UT (Ultra Twin) is a 300 kV device, corresponding to a wavelength of 1.96 pm. The electron source is a LaB6 cathode. The resolution is 1.3Å (line) and 1.7Å (dot), respectively. The instrument is equipped with a five-axis-goniometer and two axis tilting (alpha ± 30°, beta ± 20°). Imaging is done with a CCD camera covering 2.54 cm x 2.54 cm with 1000 x 1000 pixels. Image processing is carried out digitally.
As auxiliary equipment, the EDX detector should be highlighted. The active surface is 30 mm2, S-UTW windows allow for detection of all elements starting at boron. The resolution is 150 eV, the energy scope reaches 40 keV.
Our refractometer is a unique, custom designed product of SLS Systemtechnik. The device features two light sources (405 and 635 nm), beam displacement is measured in a range from -0.2° to 2.2° at a maximum dn of 0.038°. The precision is 10-4°, yielding refractive numbers in six digit precision. The refractometer can be operated at up to 80°C. This is a absolute measurement - beam displacement is amplified optically by means of a prism cascade and projected onto a CCD chip, yielding intensity spectra for analysis on the internal computer. This principle of measurement distinguishes this device from typical differential refractometers currently available.
Our Bechstein piano, built 1881, is no longer in our lab since we moved from our first location to the Science Park Potsdam-Golm in 2006. However, we have been pursuaded to leave this instrument on our website nevertheless. So, if you want to hear Nanolytics' manager play Alexander Skjrabin's prelude in e flat minor, feel free to click onto the image.