Pioneered by Beckman Coulter, most laser diffraction manufacturers use the above approaches, wide angular detecting range and short wavelength, to size small particles. However, when sizing even smaller particles that are tens of nanometers in diameter, it cannot be achieved using only these two approaches. Any further increase in scattering angle will not yield any significant improvement due to the everslower angular variation. For particles smaller than 200 nm, even by taking advantage of the above two approaches, it is still difficult to obtain an accurate size. One is to extrapolate from the measured lower limit to an even lower limit, sometimes even beyond the theoretical lower sizing limit of 10 nm. Certainly this brings uncertainty or even completely wrong information in the extrapolated region.

  Vertically polarized scattered light has different scattering patterns and fine structures from that of horizontally polarized light for small particles. The main characteristic of the horizontal scattering intensity (Ih) for small particles is that there is a minimum around 90 degrees. This minimum shifts to larger angles for larger particles. Thus, although both vertical scattering intensity (Iv) and (Ih) have only small contrast in the case of small particles, the difference between them can reveal a more distinguished fine structure, thereby making the sizing of small particles possible. Combining polarization effects with wavelength dependence at large angles, it can extend the lower sizing limit to as low as 10 nm, almost reaching the theoretical limit. This combined approach is known as the Polarization Intensity Differential Scattering (PIDS) technique patented by Beckman Coulter.

  Beckman Coulter is using PIDS Technology, an approach to use the polarization effects of the scattered light. PIDS relies on the transverse nature of light. It consists of a magnetic vector and an electric vector at 90° to it. When a sample is illuminated with a light of a given polarized wavelength, the oscillating electric field establishes a dipole oscillation of the electrons in the sample. These oscillations will be in the same plane of polarization as the propagated light source. The oscillating dipoles in the particles radiate light in all directions except that of the irradiating light source. PIDS takes advantage of this phenomenon. Light at three wavelengths (475, 613 and 900 nm) sequentially irradiates the sample, with first vertically and then horizontally polarized light.

  Beckman Coulter LS13320XR Multi-Wavelength Particle Size Analyzer with PIDS Technology, combined with laser diffraction and full implementation of both Fraunhofer and Mie Theories , measures the scattered light from the samples over 132 detectors and a range of six different angles. By analyzing the differences between the horizontally and vertically radiated light for each wavelength, enables direct detection of particles as small as 10 nm to 3,500 µm. Therefore, LS13320XR Particle Size Analyzer is the most versatile and sophisticated laser diffraction particle sizing analyzer that offer the highest resolution, reproducibility and unsurpassed accuracy of multiple particle sizes in a single sample which help the user streamline workflows to optimize efficiency. Assisted by ADAPT Software that support 21 CFR Part 11 features simplifies method creation which includes an integrated optical constants database for standardized measurements thus automatically highlights pass/fail results for faster quality control. With the build in auto-modality, no prior knowledge of sample distribution needed in order to obtain a correct result. And by comparing with customer product’s goldern distribution curve created by their R & D department, the quality department can match with their daily output for quality monitoring. It requires only 2 clicks from start measurement to result and a helpful user diagnostics keep you informed for streamlines workflows to save time.

  Validation is a must for Good Manufacturing Practices and other regulatory requirements. Therefore the LS 13 320 XR analyzer supports GMP with specific tools for Installation qualification (IQ) and Operational Qualification (OQ).

  With its availability of dry & liquid module, a diverse vast majority of the materials colloids and emulsions included can be measured in nanosizing or micro sizing by their size distribution profile. The samples are from range of industries, including Pharma and Life Science for drug delivery like inhalers; construction like Cement, asphalt, Paints & metal powders; cosmetics, lotions, and other personal care products; Polymers and other carbon like graphite, diamond, fullerenes, carbon nanotubes, and graphene has unique properties and applications across different industries.