PN3621 MALS Detector

PN3621 Multi-Angle Light Scattering Detector

Since the 1990s Postnova has been a leading innovator and developer of special advanced online Light Scattering solutions for coupling with chromatographic separation systems. The first model was the PD2000 - Static Light Scattering detector for coupling with Asymmetric Flow FFF. Later on the models PN3020 SLS and PN3070 MALS have been launched. Based on over two decades of practical experience, Postnova has collected a unique competence in the area of Laser Light Scattering and has developed the unique PN3621 MALS - Multi-Angle Light Scattering detector series. The model PN3621 MALS is a completely new type of high performance MALS detector system with a unique range of specifications.

Maximum Angle Number

The Postnova PN3621 MALS detector system employs full 21 angles and has the broadest angular range of any commercial light scattering instrument available today. These 21 angles are crucial to fulfil the high requirements set for accuracy for measuring complex particular samples, ensuring the highest precision in molecular weight and particle size determination. With 21 angles the PN3621 can achieve the highest quality data fit for the most scientifically meaningful results in your laboratory, especially for high molar mass polymers and large particles.

Unique Low Angle Range

The precision of molar mass and particles size determination is not only dependent on the number of angles but also on the number of low angles which are available for calculation. Especially the angles between 0° and 35° are the most important angles for correct and precise molar mass and size determination. Typically in the past, Static Light Scattering has been often limited in use as low angles have not been available or, when available, just do not work properly. The lack of low angles can be tolerated when investigating smaller species, such as proteins or macromolecules, where there is no angular intensity dependence. But for larger and more complex samples, such as branched polymers, high molar mass macromolecules, large protein aggregates and nanoparticles, the existence of high quality low angles are critical for precision and accuracy. The new Postnova PN3621 MALS overcomes these limitations and offers a complete set of stable working low angles, starting from 7°, 12°, 20° and 28° onwards.

Clean Vertical Flow Cell

MALS is typically being used to measure larger sample species, such as protein aggregates, high molar mass macromolecules and particles. Because of their size and fragile nature these samples have to be treated in a gentle way to avoid any alteration. Potentially shear forces, chain degradation, conformational changes and deterioration or complete loss of bioactivity can be induced by highly turbulent light scattering cells. Also aggregation, adsorption and sedimentation phenomena can cause trouble inside light scattering cells, especially when they have edges, dead volumes or right angle flow path changes inside. The new Postnova PN3621 avoids all these limitations and offers a vertical flow cell where the sample can pass through easily without any obstacles in its way. The flow cell has no right angel entry and outlets which could induce shear forces or cause particles to settle and adsorb.

Advanced Electro Optics

The PN3621 MALS employs the latest opto-electronic designs, including digital signal processing for each of the 21 angles. The electronics is based on a true 24 bit resolution AD system and offers a broad dynamic signal range. For maximum flexibility it is possible to read-in up to 3 external analogue signals. The PN3621 has the smallest footprint available in the market, saving rare lab space and allowing a flexible use at different locations and also seamlessly fits into the line of other Postnova products such as the PN3150 Refractive Index detector.

Broadest Application Range

Because of its unique design and advanced performance features, the instrument is ideally suited for the most challenging applications from various areas in science and technology:

  • Biotechnology: Alginates, Carrageenans, Hyaluronic Acids, Cell Organelles, Exosomes
  • Biopharmaceutical: Peptide, Protein, Antibody, Virus Aggregates and Conjugates
  • Food and Agro Science: Starches, Pectins, Polysaccharides, Proteins, Casein Micelles
  • Polymer Science: Rubbers, Latex Dispersions, Polyolefins, Polyelectrolytes
  • Environmental Research: Humic-Fulvic Colloids, Iron Oxides, Clays, Silica Particles
  • Nanotechnology: TiO2, CNT, C60, Latex, ZnO Nanoparticles and Silica Nanoparticles
Sample Cell Volume:

63 µL

Pressure Stability:

5 bar

Light Scattering Volume:

< 7.8 nL

Wetted Parts:

Glass, Stainless Steel, PTFE +25 % carbon

Solvent Compatibility:

Aqueous and organic solvents with the same flow cell

Light Scattering Angles:

7°-164° at 21 Angles
0-4 Volt at 24 Bit
0.24 nV Resolution

Signal Processing:

DSP on every single Photo Detector, Different Filter Algorithms possible

Molar Mass Range:

Approx. 103 to 109 Daltons depending on sample

Radius of Gyration Range:

Approx. 8 nm to 500 nm depending on sample

Laser Specifications:

532 nm (green)
2.5 – 50 mW adjustable other wavelength and filter options available on request

Laser Life Time:

Approx. 10.000 hours

Safety Functions:

Vapor Sensor
Leak Sensor

Cell Temperature Control:

10°C above Room Temperature up to 60°C
Stability ± 0.01°C at 35°C


46 cm x 26 cm x 16 cm

Shipping Weight :

17 kg

Power Requirements:

100 - 240 V, 50/60 Hz, 155 W, Universal Power Input

Computer Requirements:

Needs a PC/System with a free Ethernet connection or a Ethernet Hub for operation!

Electronic Inputs/Outputs:

Error In/Out, Injection Ready
In/Out, Ethernet Interface

Environmental Conditions:

20 – 80 % relative humidity (noncondensing) at an ambient temperature range of 4 – 30°C (when the laser is activated above 10°C)



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