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An entry level system for the measurement of particle size and molecular size at a 90 degree scattering angle using Dynamic Light Scattering, also with the ability to measure zeta potential and electrophoretic mobility using Laser Doppler Microelectrophoresis, and molecular weight using Static Light Scattering.

Overview

The Zetasizer Nano ZS90 is the perfect lower cost solution  when the ultimate in sizing sensitivity is not necessary, or where identical results to a legacy system with 90 degree scattering optics is required.

  • Size measurement from 0.3nm (diameter) to 5 microns using 90 degree scattering optics
  • Zeta potential of proteins and particles from 3.8nm up to 100 microns (diameter) using patented M3-PALS technology
  • Molecular weight measurement down to 9,800Da
  • A Quality Factor gives confidence in the data
  • The Expert advice report gives help to improve sample preparation or the measurement procedure
  • 21CFR part 11 software option enables compliance with ER/ES
  • Research software option gives access to further features and analysis algorithms for the light scattering specialist
  • Automation of measurements using an autotitrator option
  • Alternative laser, 50mW at 532nm for samples incompatible with the standard 633nm laser fitted.
  • Optical filter option to improve measurements with fluorescent sample
  • Temperature range extension option to 120ºC

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How it works

The Zetasizer Nano ZS90 incorporates three techniques in a single compact unit, and has a range of options and accessories to optimize and simplify the measurement of different sample types.

Dynamic Light Scattering at a 90 degree angle is used to measure particle size and molecule size. This technique measures the diffusion of particles moving under Brownian motion, and converts this to size and a size distribution using the Stokes-Einstein relationship.

Laser Doppler Micro-electrophoresis is the technique used to measure zeta potential. An electric field is applied to a solution of molecules or a dispersion of particles, which will then move with a velocity related to their zeta potential. This velocity is measured using a patented laser interferometric technique called M3-PALS (Phase analysis Light Scattering). This enables the calculation of electrophoretic mobility, and from this the zeta potential for the accurate measurement of a wide range of sample types and dispersion media including high salt concentrations and non-aqueous dispersants.

Static Light Scattering is used to determine the molecular weight of proteins and polymers. In this technique, the scattering intensity of a number of concentrations of the sample is measured, and used to construct a Debye plot. From this the average molecular weight and second virial coefficient can be calculated.
This measurement is very demanding on the stability of the whole system, and means that every element of the design has been optimised to ensure accuracy and repeatability

Software
The software is designed to be versatile and rich in features without compromising ease of use. Standard Operating Procedures (SOP) simplify routine measurements, a quality factor gives a single place to look for the success of a measurement, and expert advice is given to assist with data interpretation.

Options
The MPT-2 Autotitrator enables the study of the effect of changes in pH, conductivity, or any additive to be automated.
A range of disposable and reusable cells are available to optimise the measurement in terms of sample volume, concentration and for flow measurement.

Other options include filters to improve the measurement of fluorescent samples, a temperature range extension to 120ºC and a viscometer to determine the sample viscosity to the accuracy required for the techniques used.

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Specification

Particle size and molecular size

Parameter

Specification

Measurement range:
0.3nm – 5.0 microns* (diameter)
Measurement principle:
Dynamic Light Scattering
Minimum sample volume:
20µL
Accuracy:
Better than +/-2% on NIST traceable latex standards
Precision/Repeatability
Better than +/-2% on NIST traceable latex standards

Zeta potential

Parameter

Specification

Measurement range:
3.8nm – 100 microns*
Measurement principle:
Electrophoretic Light Scattering
Minimum sample volume:
150µL
Accuracy:
0.12µm.cm/V.s for aqueous systems using
NIST SRM1980 standard reference material

Molecular weight

Parameter

Specification

Measurement range:
9,800Da – 20M Da*
Measurement principle:
Static Light Scattering using Debye plot
Minimum sample volume:
20µL (3-5 sample concentrations required)
Accuracy:
+/- 10% typical
Patents granted:
M3, Mixed mode measurement
UK 2361772, EP1154266, US7217350, JP2002005888
Temperature control range:
0ºC - 90ºC +/-0.1**, 120ºC option
Light Source:
He-Ne laser 633nm, Max 5mW
Laser safety:
Class 1
Power: (V, Hz, VA)
100VA

Weight and dimensions:

Parameter

Specification

Dimensions (W, D, H)
320mm, 600mm, 260mm (W,D,H)
Weight: (kg)
21

Operating environment:

Parameter

Specification

Temperature:
15°C – 40°C
Humidity:
35% - 80% non-condensing

Software:

Parameter

Specification

Operating platforms:
Windows XP, VISTA, Windows 7
(compatible only with 32 bit versions of
Windows XP Pro and Windows 7)

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Accessories

A range of accessories are available to make life easier, or to add capability to the system

MPT-2 Autotitrator img

Automates experiments to study the effect of a change in sample conditions such as pH, conductivity, or the concentration of an additive. Up to three titrants can be used to increase and decrease pH for example.

See the MPT-2 Autotitrator
SV-10 viscometer img

An extremely simple and fast method of measuring the viscosity required for molecular size and zeta potential measurements. In 15 seconds the viscosity of 10mL of sample or dispersant can determined to an accuracy of 1% of samples with as low a viscosity as water. Water jacket supplied for temperature control (Note: Water bath required and available at additional cost)

See the SV-10 viscometer

Factory fitted options


50mW 532nm DPSS laser

For use where the sample is incompatible with the standard 633nm laser, either because the sample absorbs or fluoresces, or the sample is photosensitive.

The addition of this option does not affect the system specifications

Narrow band filters

Useful where the sample fluoresces. Will select the scattering from non-fluorescing particles and improve the signal to background ratio

High temperature capability

Increases the high temperature capability from 90ºC to 120ºC. Suitable for samples in wax media that melt above 90ºC

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