ANALYTICAL SUPPORT OR TECHNIQUES
Analytical Services: The characterization of nanomaterials is generally done with a probe which may consist of photons, electrons, neutrons, atoms, ions or even atomically sharp pins. For nanomaterials, the probing light or particle often has varying frequencies, ranging from gamma to infrared rays or beyond in the case of photons or hyper thermal (<100 keV) to relativistic energies in case of particles. The resulting information can be processed to yield images or spectra which reveal the topographic, geometric, structural, chemical or physical details of the material. Several techniques are available under the broad umbrella of characterization of materials and a systematic application of one or more techniques leads to a complete understanding of the nanomaterials.
Analytical Services: strong scientific knowledge and experience in the regulatory requirements of both the international and domestic industry market, analytical development group of NANOSHEL has evolved to interleave with drug discovery, pharmaceutical development and manufacturing. State-of-the-art technologies and instrumentation along with close collaboration with synthetic organic chemists ensures the highest quality project execution that the right questions are asked and the right tools are used to solve even the most difficult problems. Typically, these can range from identifying an impurity in a manufacturing process, degradation products formed on storage or characterization of a reference standard – all the way to a full Physical & Chemical Characterization Study for a range of nanomaterials. NANOSHEL analytical development group supports projects in an integrated services motif, and ensures that the most progress is made in a timely and cost-effective manner.
- Purity testing of starting materials and raw materials
- Structural identification of impurities and degradation products
- Structural elucidation and chemical characterization of the intermediates and final compound
- Physical & Chemical Characterization Study of the compounds provided by customers
NANOSHEL offers a variety of Analytical Services, such as
- Ultraviolet/Visible/Infrared (UV/Vis/IR) spectroscopy:
Ultraviolet/Visible/Infrared (UV/Vis/IR) spectroscopy is a technique used to quantify the light that is absorbed and scattered by a sample (a quantity known as the extinction, which is defined as the sum of absorbed and scattered light). In its simplest form, a sample is placed between a light source and a photo detector, and the intensity of a beam of light is measured before and after passing through the sample. These measurements are compared at each wavelength to quantify the sample’s wavelength dependent extinction spectrum. The data is typically plotted as extinction as a function of wavelength. Each spectrum is background corrected using a “blank” – a cuvette filled with only the dispersing medium – to guarantee that spectral features from the solvent are not included in the sample extinction spectrum.
Nanoparticles have optical properties that are sensitive to size, shape, concentration, agglomeration state, and refractive index near the nanoparticles surface, which makes UV/Vis/IR spectroscopy a valuable tool for identifying, characterizing, and studying these materials. Nanoparticles made from certain metals, such as gold and silver, strongly interact with specific wavelengths of light and the unique optical properties of these materials is the foundation for the field of plasmonics. At Nanoshel we have developed numerical modeling algorithms that can be used to predict the optical properties of various nanoparticles allowing for comparison between theoretical and measured properties.
- FTIR Spectroscopy:
FTIR Spectroscopy Molecules and crystals can be thought of as systems of balls (atoms or ions) connected by springs (chemical bonds). These systems can be set into vibration, and they vibrate with frequencies determined by the mass of the balls (atomic weight) and by the stiffness of the springs (bond strengths). The molecular and crystal vibrations are at very high frequencies ranging from 1012 – 1014 Hz (3-300 µm wavelength), which are in the infrared (IR) region of the electromagnetic spectrum. The term ‘FTIR’ refers to Fourier Transform Infrared Spectroscopy, when the intensity-time output of the interferometer is subjected to a Fourier Transformation to convert it into the familiar infrared spectrum (intensity versus frequency). The identities, surrounding environments and atomic arrangements, and concentration of chemical bonds that are present in the sample can be determined.
- Powder X-Ray Diffraction:
X-Ray Diffraction (XRD) is a very important technique that has long been used to address numerous issues related to the crystal structures of solids, including lattice constants and geometry, identification of unknown materials, orientation of single crystals, preferred orientation of polycrystals, defects, stresses etc. In XRD, a collimated beam of X-rays with a wavelength typically ranging from 0.7 to 2 Å, is incident on a specimen and is diffracted by the crystalline phases in the specimen according to Bragg’s Law : nλ = 2d sin θ where, n is the order of diffraction, d is the spacing between atomic planes in the crystalline phase and λ is the X-ray wavelength. The intensity of the diffracted X-rays is measured as a function of diffraction angle 2θ and the specimen’s orientation. The diffraction pattern is used to measure the specimen’s crystalline phases and measure its structural properties.
- Transmission electron microscopy:
Transmission Electron Microscopy (TEM) is a well known technique for imaging solid materials at atomic resolution. Structural information can be acquired both by (high resolution) imaging as well as by electron diffraction. Additional detectors allow for elemental and chemical analysis down to sub-nanometer scale. The greatest advantages that TEM offers are the high magnification ranging from 50 to 106 and its ability to provide both image and diffraction information from a single sample. TEM instruments with resolving powers in the vicinity of 1 Å are now common and have become one of the most essential tools for the characterization of nanomaterials. In TEM, the electrons from a source such as an electron gun (W or LaB6) enter the sample, are scattered as they pass through it, are focused by the objective lens, are amplified by the magnifying projector lens, and finally produce the desired image.
- X-ray crystallography
X-ray crystallography is a useful tool for identifying the atomic and molecular structure of a crystal, in which the crystalline atoms cause a beam of incident X-rays to diffract into many specific directions. By measuring the intensities and angles of these diffracted beams, a crystallographer is capable of producing a 3D picture of the electron density within the crystal. From this electron density, the positions of the atoms in the crystal can be determined, as well as the chemical bonds, the disorder and various other information.
- Scanning electron microscopy:
Scanning electron microscopy is a great way to obtain information about a sample’s surface topography and composition in industries such as microelectronics, semiconductor, medical devices, general manufacturing, insurance and litigation support, R&D, and food processing.
Benefits of SEM include:
- Digital image resolution as low as 15 nanometers
- Magnification for all imaging is calibrated to a traceable standard. Image analysis for coating thicknesses, grain size determinations and particle sizing can be applied to the saved images.
- Qualitative elemental analysis, standard less quantitative analysis, x-ray line scans and mapping can be performed on both of the SEM systems.
SEM is a method for high resolution surface imaging. The SEM uses electrons for imaging, much as light microscopy uses visible light. The advantages of SEM over light microscopy include greater magnification (up to 100,000X) and much greater depth of field. Different elements and surface topography emit different amounts of electrons; the varying amounts of electrons are responsible for the contrast in the electron micrograph (picture) which is representative of surface topography and composition.