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Chapter 5

Microrheology

Page 5-8

MAN 0487

Tracer

The Tracer SOP window shows details about the tracer used in the measurement. 
Press 

Select

 to open the tracer manager window where the tracer to be used can be 

selected. 

Measurement - Advanced

This window is the same as the standard size 

Measurement - Advanced

, except 

for the addition of the 

Acceptable zeta ratio (%) 

setting.

Settings

Description

Select

Highlight the tracer required and press OK. The Tracer SOP 
will now be populated with the selected tracer.

Edit

Enables the editing of the nominal tracer size.

Notes

Add any additional information.

Settings

Description

Acceptable zeta 
ratio (%) 

This is the acceptable ratio between the zeta potential meas-
ured for the tracer particles in dispersant alone, and of that 
measured in dispersant and sample.

Summary of Contents for Zetasizer Nano Series

Page 1: ...nd MRK1378 01 Malvern Instruments Limited Enigma Business Park Grovewood Road Malvern Worcs WR14 1XZ U K Tel 44 0 1684 892456 Fax 44 0 1684 892789 www malvern com Q SelAccessories Guide Zetasizer Malv...

Page 2: ......

Page 3: ...Zetasizer Nano accessories guide MAN0487 Issue 1 1 April 2013...

Page 4: ...any part of this publication is allowed without the express written permission of Malvern Instruments Ltd Head office Malvern Instruments Ltd Enigma Business Park Grovewood Road Malvern Worcestershire...

Page 5: ...ta potential cell 2 29 Surface zeta potential cell Introduction 3 1 Measurement technique 3 3 Preparation for measurement 3 4 Controlling an SZP measurement via an SOP 3 10 Performing the measurement...

Page 6: ...Microrheology utilities 5 3 Exporting the microrheology data 5 4 Controlling the microrheology measurement via an SOP 5 6 Microrheology measurement process 5 9 Displaying the microrheology measuremen...

Page 7: ...d the health and safety information in the basic guide before operating the system This manual focuses on specific issues of the Zetasizer Nano accessories that are not covered by the above manuals Ac...

Page 8: ...t ZEN1020 Surface zeta potential cell Cell intended for the measurement of the zeta potential at the sur face of a flat material in an aqueous environment Use with DTS0012 and PCS1115 cuvette describe...

Page 9: ...o fill each cell with sample and then insert into the Zetasizer Nano instrument Some accessories require configuration of the software and SOP parameters Where required the software controls are ident...

Page 10: ...s available for use with the Zetasizer Nano when connected to a SEC system It includes the flowcell ZEN0023 Connection use and operation of a flow mode optioned Zetasizer Nano is described in the Flow...

Page 11: ...for the Nano ZS The Zetasizer Nano ZSP has increased capability for the measurement of small and weakly scattering molecules and particles This increased sensitivity improves the measurement of zeta p...

Page 12: ...Chapter 1 Introduction and accessory range Page 1 6 MAN 0487...

Page 13: ...their use and application The aspects covered are Identification of each cell of the dispersion units with guidance on selection How to fill each cell with sample and then insert into the Zetasizer Na...

Page 14: ...e The two trays that hold the cuvettes can be removed for cleaning The cuvette holder provides a place to store the thermal cap during changeover of cells The cap is released by raising the cap and li...

Page 15: ...The optical quality of the cells is vitally important when performing molecular weight and low concentration protein measurements derived count rate 100kcps therefore glass or quartz type cuvettes sh...

Page 16: ...ty Good to very good Good to very good Minimum Sample volume 0 75ml 1ml Advantages Low cost Single use disposable no cleaning Use with MPT 2 Titrator No sample cross contamination Fast sample change o...

Page 17: ...0 C systems Zetasizer Nano S90 ZS90 Zetasizer V Requires careful filling to avoid bubbles Not resistant to organic solvents Unsuitable for use at high temperatures above 70 C Only applicable to system...

Page 18: ...tor Highest optical quality Can use nearly any dispersant Low sample volume Disadvantages Requires cleaning after measurement With manual use requires careful filling to avoid bubbles Requires cleanin...

Page 19: ...specific advice will be given Size cells and cuvettes All size cells should be rinsed cleaned with filtered dispersant before use Molecular weight cells and cuvettes All molecular weight cells should...

Page 20: ...e depends on the actual cell type and it is easier to ensure a certain depth of the sample in the cell This minimum is 10mm from the bottom of the cell the measurement is made 8mm from the bottom of t...

Page 21: ...sensitivity of the S90 and ZS90 means that they are unlikely to be suitable for the majority of molecular weight measurements Flowcells Flowcells will be filled during the measurement procedure Refer...

Page 22: ...n using the MPT 2 Titrator Always minimise the tubing within the cell area before inserting into the pinch valve channel Follow the instructions in the previous section on how to insert the cell Do no...

Page 23: ...area Cleaning cuvettes Two main types of cuvette are available Disposable polystyrene Do not clean and re use disposable cuvettes It gives inaccurate results Reusable glass or quartz The cleaning pro...

Page 24: ...provide a low cost alternative to previous reusable quartz capillary cells The stoppers can be replaced with Luer connectors to provide leak free connection to the optional MPT 2 Titrator Size measure...

Page 25: ...illing a cell for a protein mobility measurement involves a different technique Refer to the Advanced protein features chapter DTS1070 cell The cell name DTS1070 will be identified on the central sect...

Page 26: ...rt a cell stopper in each port Remove any liquid spilt on the electrodes contacts Note The stoppers must be fitted before a measurement is performed Ensure that one stopper is fitted firmly and the ot...

Page 27: ...t do form Turn the cell upright and continue to inject slowly until the sample is at the top of the electrodes Check again for bubbles in the cell Tap the cell gently to dislodge these ill 7938 Check...

Page 28: ...sation of the cell Inserting the folded capillary cell ill 8507 Place a thermal contact plate into the recess on either side of the folded cap illary cell The plates provide increased temperature stab...

Page 29: ...pillary cell orientation and insertion The clear folded capillary zeta potential cells can show significant differences in sample count rate depending on the orientation of the cell in the cell holder...

Page 30: ...below for connecting the cell for the Titrator Always minimise the tubing within the cell area before inserting into the pinch valve channel The tubing is attached to the folded capillary cell using...

Page 31: ...rodes The cell should then be flushed through with water as described below To clean the cell Fill one syringe with de ionised water or the dispersant Place the full syringe in one of the sample ports...

Page 32: ...er of samples can be prepared and the Dip cell inserted to measure each one in turn For aqueous samples the Dip cell can be used in conjunction with the disposable polystyrene DTS0012 For non aqueous...

Page 33: ...ween the sample electrodes The cuvette must not be filled more than the recommended maximum depth of 10mm Tilt the cuvette to a maximum angle of 45 Slowly insert the cell into the cuvette until the me...

Page 34: ...p cell and cuvette can be removed together If adequate purchase cannot be obtained on both parts then the following procedure is recommended Lift the Dip cell up out of the cuvette but before complete...

Page 35: ...ts especially between different types of sample Cross contamination between samples can seriously affect the results Caution Do not immerse the complete cell Only the sample electrodes must dip in to...

Page 36: ...ctrodes with pure dispersant Note The electrode holder is made from Natural PEEK Polyetheretherketone which is resistant to a wide range of chemical products However seek advice from Malvern and the s...

Page 37: ...he electrodes Description ill 8450 The High concentration cell is intended primarily for the measurement of zeta potential of concentrated aqueous samples The cell can be used in conjunction with the...

Page 38: ...e Titrator in the same manner as the Folded capillary cell ill 8449 The metal face of the cell must face the front of the instrument this is to ensure good thermal contact between cell and instrument...

Page 39: ...8447 Remove the screw cap Separate the two halves of the cell by pulling the rear casing vertically away from the metal front Note how the electrode chambers and quartz measurement cell block are ass...

Page 40: ...minutes Rinse with water once cleaned Electrode chambers and port Electrode Chamber Scrub gently with interdental brush and Hellmanex then scrub with copious amounts of de ionised water Smaller inter...

Page 41: ...in this manual Description ill 8687 The surface zeta potential cell is intended for the measurement of the zeta potential at the surface of a flat material in an aqueous environment The cell is a dip...

Page 42: ...Chapter 2 General cells and cuvettes Page 2 30 MAN 0487...

Page 43: ...ype device and can be used with 1ml cell DTS0012 and PCS1115 It is incompatible with the MPT 2 Titrator The cell consists of a height adjustable sample barrel in which the sample is glued onto a sampl...

Page 44: ...components to prepare load and set the sample Surface zeta potential cell with palladium electrodes A 12 well plate for storing the samples 10 PEEK sample holders A screwdriver for cell tightening For...

Page 45: ...smotic surface flow while at distances further from the surface it will be dominated by the electrophoretic motion of the tracer itself The graph below shows a typical plot of reported zeta displaceme...

Page 46: ...in the next sections once these are com plete the measurement can be performed Loading the surface zeta potential cell with sample Inserting the surface zeta potential cell into the instrument Loadin...

Page 47: ...securely held in place for the duration of the experiment Inserting the surface zeta potential cell The insertion of the surface zeta potential cell into the Zetasizer Nano is done in three stages Fi...

Page 48: ...mbly into the tool so that the white mark on the cell is facing the front of the tool indicated by the white spot and tilting forward Adjust the cell cap to alter the sample barrel position until the...

Page 49: ...ing the tracer particles Sufficient suspension should be added to the cell so that the sample electrodes and screw are all completely submerged This is approximately 1 2 ml Fill the cuvette the prepar...

Page 50: ...e holder barrel and elec trodes are covered As the cell is inserted it displaces the sample so any bub bles will be pushed out from the top of the electrode gap Once the electrodes are covered bring t...

Page 51: ...ial cell from the drop down list Set the Attenuator to 11 To identify if your sample is aligned correctly open the instrument lid and rotate the cell cap clockwise in increments of approximately 1 8 t...

Page 52: ...e are described in the above manual The other SOP sections are specific to the SZP cell being used these are described below Also note that some of the other dialogue pages will alter slightly to acco...

Page 53: ...will be the only cell choice available The Zetasizer software will configure all settings and parameters to match this cell The default selection is the Surface zeta potential cell SZP measurement The...

Page 54: ...ements made at each displacement away from the surface and the length of any delay between repeat measurements SZP displacement The SZP displacement options define the distances to be used during a su...

Page 55: ...n options are the same as standard measurement duration options available during normal zeta potential measurements Tracer measurements The tracer measurements options define the number of repeat meas...

Page 56: ...o be set It is generally best to leave these set to default Size ranges and measurement thresholds can be applied to the analysis to filter spurious peaks prior to the analysis being performed These c...

Page 57: ...ow which enables various attributes of the analysis model to be altered These include the measured zeta Display range and the measurement thresholds If it is known that all particles within the sample...

Page 58: ...will set the distance to the first required displacement position This is a manual operation and the user must open the cell area lid turn the head of the cell the specified amount then close the lid...

Page 59: ...ven to set the cell to the next measurement position This process will continue until all measurements have been made at all the positions specified in the SOP and the surface zeta potential measureme...

Page 60: ...m the main menu With the Edit result window open the Debye length model tracer material and dispersant properties can then all be changed The surface zeta potential edit result option allows points to...

Page 61: ...r the measurement it is recommended that this is disposed of and a new one used for all subsequent measurements General cleaning As a complete assembly the cell can be cleaned using de ionised water o...

Page 62: ...nst the materi als identified below before inserting a sample It is also recommended that a test is performed on the material with the sample before more permanent usage is undertaken With proper use...

Page 63: ...fitted an option part number label will be attached to the front of the cuvette holder The flow mode option is included as a standard fitment on the Zetasizer Nano ZSP Flow mode The Flow mode option...

Page 64: ...s to be monitored Applications Applications for this feature include use as a chromatography detector and a process monitor Separations detector The Zetasizer Nano can be connected to a size exclusion...

Page 65: ...and ZS means that many processes can be monitored without further sample preparation simplifying the measurement Note The method of sampling the process and transferring this to the Zetasizer is not p...

Page 66: ...ware saved as a text file and inserted into a spreadsheet software package such as Microsoft Excel for analysis This is done using the Export flow result macro option in the Tools menu If this macro i...

Page 67: ...will display the window below ill 8822 The window shows the following Chromatogram This shows the flow mode plot By default the Intensity trace is displayed on the left y axis and the Z average mean...

Page 68: ...e to select a region of the chromatogram which is highlighted in purple By right clicking the mouse it is then possible to perform a DLS analysis of this region This calculates and intensity weighted...

Page 69: ...ts dialogue Choose Con figure and then disable the option to Filter flow mode data to do this With reference to the originally attributed baseline level the software will display any peaks that may ha...

Page 70: ...plained later in this chapter Peaks tab The Peaks tab displays all the details about the calculated peaks shown in the flow mode plot To display a peak s details either select a blue peak bar in the p...

Page 71: ...put 1 2 and Flow settings will be included in the SOP selections The SOP Editor and setup is described in full in the Zetasizer Nano user manual Most of the SOP sections are common to Measurement type...

Page 72: ...With the Enable input check box selected the input condi tions required for the external signal can be setup Input name Use Input name to name the type of input Use a name that represents the signal o...

Page 73: ...external detector and the Zetasizer Nano This parameter ensures that data recorded by the Zetasizer can be over plotted from the same elution point This value will be obtained from the external detec...

Page 74: ...urement duration setting may affect the accuracy and repeatability of the results In Measurement duration input the total measurement time or volume amount required and adjust the units to suit Time o...

Page 75: ...all other SOP windows refer to the size SOP section Settings Description Flow rate Input the flow rate of the sample through the instrument and connecting tubing This value is taken from the external...

Page 76: ...he measurement progresses The result view will be updated after every run of the measurement The Result tab is named after the result view chosen the result view shown above is Flow trace vs Time Diff...

Page 77: ...ement record and then select the appropriate report tab The report will show all appropriate measurement information for that record Standard report flow mode measurements The standard Flow mode repor...

Page 78: ...e three main peaks in the measurement will also be shown displaying the sample intensity width molecular weight and start and end flow volumes Additionally a the flow trace result graph will be displa...

Page 79: ...icrorheology as it is a cross over between DLS and rheology and allows rheological measurements of low viscosity and weakly structured samples to be made Advantages of DLS Microrheology are Rheologica...

Page 80: ...raction between the tracer particles and measurement sample The tracer is initially measured in the sample buffer dispersant or solvent alone with no sample added sample is then added and a second mea...

Page 81: ...ex viscosity Each tab page contains controls that allow different models to be fitted to the microrheology data graph It is important to note however that not all models will be applicable to all the...

Page 82: ...t destination Enter the destination and alter the parameters and settings as required To export the data as a csv file select the Browse button and alter the file extension Note if Ok is pressed the d...

Page 83: ...time is exported from the Zetasizer software in s and will be imported into the rSpace software in s Sample Name Date File Name Lag times s Times s Angular Frequency rad s Creep Compliance Plot again...

Page 84: ...l open up the SOP Edi tor The SOP Editor consists of several dialogues that can be stepped through by using the Next arrow button To edit an existing SOP choose Open SOP instead Complete the SOP Edito...

Page 85: ...Select or deselect the zeta potential and size tick boxes as required Refer to the schematic description below Load Load a saved SOP file The SOP loaded will be shown in the above entry box Edit Edit...

Page 86: ...t Advanced except for the addition of the Acceptable zeta ratio setting Settings Description Select Highlight the tracer required and press OK The Tracer SOP will now be populated with the selected tr...

Page 87: ...is a size measurement that the software uses to calculate the relaxation times and therefore the viscosity and moduli values However in order to get to this point and in order to make reliable measur...

Page 88: ...rements For the initial tests of the zeta potential the following starting concentrations are suggested Tracer in dispersant buffer or solvent only 0 5 l tracer particles to 10ml sample 0 05 l ml Trac...

Page 89: ...measurement will be difficult It is therefore important to use just enough tracer to mask the sample but not put in so much that the sample becomes turbid Note The measured size of the tracer may not...

Page 90: ...and the sample tracer systems The tracer concentration is not high enough in the sample If the tracer concentration is too low the zeta potential result will be domi nated by the sample not the tracer...

Page 91: ...dispersant buffer or solvent alone This is termed the tracer measurement Use a zeta potential cell A zeta potential cell is filled with the dispersant buffer that is to be used in the later microrheo...

Page 92: ...ntration similar to that used in the previous step Ensure the tracer and measurement sample are mixed A measurement of the zeta potential of the tracer in the measurement sample is then performed Once...

Page 93: ...y cell or disposable sizing cell Prepare a fresh measurement sample and perform a size measurement When finished a dialogue will appear indicating the next step to perform Measure size of measurement...

Page 94: ...so much that the sample becomes turbid therefore making any subsequent measurement difficult When the software is satisfied with the comparison between the two size measurements the microrheology mea...

Page 95: ...tracer size can be measured once and the same value can be set in the SOP by checking the edit box next to the nominal tracer size and changing the nominal tracer size to the size that has been measur...

Page 96: ...g the Cox Merz rule This rule is generally only fully applicable for simple systems and that the differences between complex viscosity and shear viscosity increases as the sample structure becomes mor...

Page 97: ...e Page 5 19 A standard report MSD The standard microrheology report MSD mean squared displacement M gives similar information as seen in a standard size and zeta potential report plus additional infor...

Page 98: ...Chapter 5 Microrheology Page 5 20 MAN 0487...

Page 99: ...iffusion barrier measurement technique a description of this follows A measurement process that reduces the risk of aggregation but also capable of identifying any aggregates that are formed and asses...

Page 100: ...all recorded sub runs is reported into the record view During the measurement proper running a large number of sub runs sequentially will significantly increase the risk of Joule heating of the sample...

Page 101: ...lectrodes The diffusion barrier technique protects the protein from damage by introducing a physical distance between the sample and the electrodes This is done by holding a plug of measurement sample...

Page 102: ...ein mobility measurement being performed these are described below Also note that some of the other dialogue pages will alter slightly to accommodate extra parameters necessary to perform the microrhe...

Page 103: ...epeatability of the measurement of particularly polydisperse samples All the individual runs are accumulated and then averaged to give a final zeta potential result Therefore the more runs performed t...

Page 104: ...tion Perform a size measurement With the Perform a size measurement before and after the Protein mobility measurement check box selected a size measurement will also be performed as well as the standa...

Page 105: ...mobility measurement displays are identical to those shown when performing a standard zeta potential measurement The measurement and a a description of the measurement tabs is explained in the Zetasi...

Page 106: ...once aggregated groups have been removed The average over un aggregated groups will yield the mobility of only the protein itself and not its aggregates but the number of groups included in the measu...

Page 107: ...surement information for that record Standard report protein mobility measurements Once a protein mobility measurement is completed there are a number of standard reports available for reviewing the m...

Page 108: ...ollowing tab selections are available SLS Debye plot The protein utilities function enables a static light scattering Debye plot to be constructed from freely available information or from a record ge...

Page 109: ...tion and molecular weight Also estimates the thickness of the electrostatic layer based on protein charge and ionic strength Mixture Viscosity A simple tool that calculates the overall viscosity of a...

Page 110: ...s Any of the parameters in the window box can be changed the other parameters will be instantly recalculated This can be used to investigate the sensitivity of the result to changes in any parameter F...

Page 111: ...e Table tab to begin entering data into the table To define a new concentration press the Add button The table Input values window will be displayed Specify the Concentration and Sample intensity valu...

Page 112: ...s are described in the following section Measurement parameters table Once all the concentration values have been added into the table the measurement parameters table can be used to alter the result...

Page 113: ...the residual count rate which is derived by subtracting the solvent count rate from the sample count rate Shape Model The shape model that is used to estimate the radius of gyration from the hydrodyna...

Page 114: ...ength between the molecule and the solvent This is calculated from the slope of the plot K Mol cm2 g The instrument optical constant Molecular weight MW and shape estimates The hydrodynamic size measu...

Page 115: ...sion coefficient D now known the Hydrodynamic diameter can be calculated by using a variation of the Stokes Einstein equation DH Hydrodynamic diameter k Boltzmann constant f Particle frictional coeffi...

Page 116: ...r F plus the Prolate and Oblate axial ratio will be automatically calculated and displayed in the results area If required a solvent layer can be subtracted from the hydrodynamic radius when calculati...

Page 117: ...nd the estimated molecular weight will automatically be calculated The molecular weight is displayed in four ways Hydrodynamic diameter estimate This works in the same way as above except the molecula...

Page 118: ...value press the return key afterwards and the results table will be updated Minimum Concentration Calculator By entering only the molecular weight the Sample concentration mg ml values required for pe...

Page 119: ...Protein charge Ka This tool is used to calculate Ka for the Henry equation using known size and ionic strength This tool uses the Ohshima equation for monovalent salts The second calculation calculate...

Page 120: ...gadros number 6 022 10 23 mole K Boltzmann s constant 1 38065 10 23 m2kg s2K T temperature K I ionic strength moles L This calculator allows a more specific value other than the Smoluchowski or Huckel...

Page 121: ...A dynamic Debye plot can be created by inputting the concentration points from an existing measurement then additional concentration points can be added Any of the parameters in the dialogue box can...

Page 122: ...ed Specify the Concentration and Measured diffusion coefficient values either new values or ones taken from an existing measurement To modify a concentration select it from the list and press the Modi...

Page 123: ...is completed the other will be updated Saving the dynamic Debye plot Click Save to save the parameters and other inputted data To reviewed the saved parameters at a later stage click the Load button...

Page 124: ...ere o permittivity of free space 8 8542 10 12 C Vm inverse Debye length 1 nm NA Avogadros number 6 022 10 23 mole K Boltzmann s constant 1 38065 10 23 m2kg s2K T temperature K I ionic strength moles L...

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Page 126: ...alvern Instruments Limited Enigma Business Park Grovewood Road Malvern Worcs WR14 1XZ U K Tel 44 0 1684 892456 Fax 44 0 1684 892789 www malvern com Quick start Self installation guide Zetasizer Malver...

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