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7 Troubleshooting

￭￭￭￭￭￭￭￭

47

Problem

Cause

Remedy

Technical failure.

Disconnect the USB cable from the potentio-
stat and try to switch it on again. If the green
status LED indicates that the potentiostat is on,
reconnect the USB cable.

Potentiostat - the
potentiostat
switches off during
a determination.

Battery level too low.

Connect the potentiostat to the power grid
using the USB power supply unit

4.3.1, page 21)

. Charge the battery for at least

1 hour before switching on the potentiostat
again.

SPE - liquid is found
close to the connec-
tion socket for the
SPE.

The nut is not tightened
enough.

Fasten the nut until the slot in the silicone seal
completely seals the SPE.

The silicone seal is defec-
tive.

The silicone seal is a consumable. The sharp-
edged SPEs can cut into the silicone. It is rec-
ommended to replace the silicone seal every
25 electrodes.

The supporting ring is bent.

The supporting ring deforms over time.
Replace the supporting ring when it is
deformed and therefore does not equally dis-
tribute the pressure anymore.

SPE - the SPE cannot
be inserted into the
holder.

The nut is already too tight
and seals the slot in the sil-
icone seal.

Unfasten the nut to release pressure from the
silicone seal which opens the slot for the SPE.

The supporting ring turned
out of position.

Unfasten the nut and turn the supporting ring
so that the slot in the supporting ring is con-
gruent with the slot in the silicone seal. Also
make sure that the planar side of the support-
ing ring is attached to the silicone seal.

Stirrer - the stirrer
does not rotate.

The electrode cable is not
correctly connected.

Check that the plugs are connected with the
correct orientation

(see chapter 4.2.5, page

.

The electrode cable is
loose.

Make sure that the screws of the cable con-
nections are securely tightened.

The stirring and/or waiting
time in the method is 0.

The stirrer only runs during stirring and poten-
tiostatic pretreatment. Load the method and
set the correct time for

Stirring time

,

Wait-

ing time 1

and

Waiting time 2

.

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Содержание 2.946.0010

Страница 1: ...946 Portable VA Analyzer 2 946 00x0 Manual 8 946 8003EN ...

Страница 2: ......

Страница 3: ...Metrohm AG CH 9100 Herisau Switzerland Phone 41 71 353 85 85 Fax 41 71 353 89 01 info metrohm com www metrohm com 946 Portable VA Analyzer 2 946 00x0 1 0 Manual 8 946 8003EN 2019 05 31 zu ...

Страница 4: ...techcom metrohm com This documentation is protected by copyright All rights reserved This documentation has been prepared with great care However errors can never be entirely ruled out Please send comments regarding possible errors to the address above ...

Страница 5: ...ment 14 4 1 1 Packaging 14 4 1 2 Checks 14 4 1 3 Operation site 14 4 2 Hardware installation 15 4 2 1 Stirrer 15 4 2 2 scTRACE Gold electrode 15 4 2 3 Screen printed electrode SPE 16 4 2 4 Assembling the measuring stand 18 4 2 5 Connecting the measuring stand and the potentiostat 19 4 3 Power supply 20 4 3 1 Charging the battery with power supply unit 21 4 3 2 Charging the battery via USB connecto...

Страница 6: ...strument 43 7 Troubleshooting 45 7 1 General rules for voltammetric trace analysis 45 7 1 1 Sampling 45 7 1 2 Measuring solution 45 7 1 3 Quantification 46 7 2 Hardware problems 46 7 2 1 46 7 3 Application problems 48 7 3 1 48 7 4 Some voltammetric troubles in detail 60 7 4 1 Linear working range 60 7 4 2 Potential range of an scTRACE Gold electrode 61 7 5 Dummy cell test 66 8 Technical specificat...

Страница 7: ... 18 Figure 11 946 Portable VA Analyzer potentiostat connected to measuring stand 19 Figure 12 Operation of measuring stand 34 Figure 13 Remove scTRACE Gold electrode 40 Figure 14 Remove screen printed electrode 41 Figure 15 Remove stirrer 43 Figure 16 Good and bad standard addition curves 61 Figure 17 Influence of chloride concentration on the background current of the scTRACE Gold electrode Measu...

Страница 8: ......

Страница 9: ...tentio stat is the electronic hardware to run the voltammetric measurement and the stirrer The instrument is controlled by the Portable VA Analyzer soft ware The communication between software and hardware takes place via USB cable 1 2 Intended use The 946 Portable VA Analyzer is designed for the voltammetric determina tion of samples in the area of trace analysis A potential application area is D...

Страница 10: ...h the instrument is ensured as part of the international standard IEC 61010 WARNING Only personnel qualified by Metrohm are authorized to carry out service work on electronic components Supply voltage WARNING An incorrect supply voltage can damage the instrument Only operate this instrument with a supply voltage specified for it see bottom of the instrument Protection against electrostatic charges...

Страница 11: ...cumentation Cross reference to figure legend The first number refers to the figure number the sec ond to the instrument part in the figure Instruction step Carry out these steps in the sequence shown Method Dialog text parameter in the software File New Menu or menu item Next Button or key Warning This symbol draws attention to a possible life hazard or risk of injury Warning This symbol draws att...

Страница 12: ...1 4 Symbols and conventions 4 Note This symbol marks additional information and tips ...

Страница 13: ...view 1 Status LEDs Power on Measurement running Battery level low 2 Electrode cable connector Connection socket for the cable connection between potentiostat and measuring stand Figure 2 946 Portable VA Analyzer potentiostat rear view 1 Reset button 2 I O cable connector Connection socket for the optional I O con troller cable 6 02135 010 3 ON OFF button 4 Type B mini USB connector Connection sock...

Страница 14: ...e plate 6 02708 020 2 O ring 6 01408 000 3 Measuring vessel 6 01412 000 4 Transparent ring 6 02708 030 5 Pipetting opening 6 Stirrer 6 01204 000 7 Measuring head scTRACE Gold 6 01256 010 8 Electrode cable connector Connection socket for the cable connection between measuring stand and potentiostat 9 O ring 6 01408 000 10 scTRACE Gold 6 1258 000 ...

Страница 15: ... 020 2 O ring 6 01408 000 3 Measuring vessel 6 01412 000 4 Transparent ring 6 02708 030 5 Pipetting opening 6 Stirrer 6 01204 000 7 Measuring head SPE 6 01256 020 8 Electrode cable connector Connection socket for the cable connection between measuring stand and potentiostat 9 O ring 6 01408 000 10 SPE holder 11 SPE screen printed electrode ...

Страница 16: ...t SPE holder 2 Electrical connector for SPE Connection socket for the screen printed electrode 3 Positioning support 4 Silicone seal for SPE electrode shaft 6 1244 060 5 Supporting ring for SPE electrode shaft 6 1241 210 6 Nut for SPE electrode shaft 6 1241 200 ...

Страница 17: ...More details about the software and method parameters can be found in the Portable VA Analyzer software manual 8 0105 8002EN Figure 6 Portable VA Analyzer software overview default workplace layout 1 Menu bar 2 Toolbar 3 Run subwindow 4 Messages subwindow 5 Status bar 6 Live curve 7 Graphics subwindow 8 Results subwindow 9 Curves subwindow ...

Страница 18: ... Chinese Help Information regarding the device Information regarding the software version Link to the PDF file of the manual Toolbar 6 2 New method Load and open a method with default square wave parameters Load determination Opens the dialog window to load an existing determination file By default determinations are saved in the folder USERPROFILE Docu ments Metrohm Portable VA Analyzer Determina...

Страница 19: ...s shows an overlay of voltammograms belonging to the determination The tab s Substance name calibration show the calibration curve for a substance Each calibration curve will be displayed on an individ ual tab Tabs workplace Change the view of the workplace to tabs This layout has only one subwindow Curves with a maximum of 6 tabs The tab Live curve is only displayed when an instrument is connecte...

Страница 20: ... Differential pulse Evaluation Settings related to data processing peak recognition and calibration Reprocess Reprocess the curve evaluation after deactivating individual curves or editing base points in the Results subwindow Details on the reevaluation of peaks can be found in Chapter 5 1 4 Reevaluating a determination page 28 Create PDF Open the dialog window to select the report elements which ...

Страница 21: ... for individual export the curves have to be selected in this subwindow Results subwindow 6 8 This subwindow includes 2 to 5 tabs The tab Results shows the overview of the results calculated for all substances specified in the method Evalua tion details like peak potentials and peak heights can be found on up to 4 additional tabs One tab for each substance tagged with Substance name Curves subwind...

Страница 22: ...afe transportation of the instrument 4 1 2 Checks Immediately after receipt check whether the shipment has arrived com plete and without damage by comparing it with the delivery note 4 1 3 Operation site The 946 Portable VA Analyzer has been designed for mobile application CAUTION Influence of weather conditions The instrument can be damaged as a result of direct sunlight direct exposure to water ...

Страница 23: ... Gold measuring head 6 01256 010 and the SPE measuring head 6 01256 020 1 Screw the stirrer tip 6 01204 000 onto the stirrer connector Use the 4 mm metal wrench 6 02621 000 to keep the stirrer connector from turning Rotate the stirrer tip clockwise until the stop 4 2 2 scTRACE Gold electrode Figure 8 Assembly of scTRACE Gold electrode ...

Страница 24: ... contact springs take care not to twist the scTRACE Gold while mounting it to the electrode holder The electrode base has to slide between the upper and lower springs CAUTION When mounting the scTRACE Gold to the electrode holder leave the protective cap on the electrode This is in order to avoid damage to the gold micro wire 4 2 3 Screen printed electrode SPE Figure 9 Assembly of screen printed e...

Страница 25: ...revent it from turning out of position 2 Place the supporting ring 5 5 on top of the seal with the planar side pointing towards the seal The two pins 5 3 support the position ing The slot in the supporting ring has to be congruent with the slot in the silicone seal 3 Place the nut 5 6 on the shaft Do not tighten the nut otherwise the SPE cannot be assembled with the holder b Assembling the SPE CAU...

Страница 26: ...the stop NOTICE Tilting the electrode may damage the connection socket for the SPE behind the silicone seal 3 Tighten the nut in a clockwise direction to fix the electrode and seal the inside of the holder against liquids 4 2 4 Assembling the measuring stand Figure 10 Assembly of measuring stand ...

Страница 27: ...measuring head down until the stop 4 2 5 Connecting the measuring stand and the potentiostat Figure 11 946 Portable VA Analyzer potentiostat connected to mea suring stand 1 Measuring stand 2 Electrode cable 6 02135 000 3 Potentiostat Measuring stand and potentiostat are connected via the electrode cable 6 02135 000 This procedure equally applies for the scTRACE Gold mea suring stand 6 5340 010 and...

Страница 28: ...ocket 3 8 4 8 of the measuring head Take care of the correct orientation of the plug and tighten the screw to secure the connection 4 3 Power supply The potentiostat is equipped with a rechargeable battery This allows mobile use independent from an external power grid NOTICE To fully charge the battery it is recommended to connect the potentio stat to the power grid via the power supply unit ...

Страница 29: ...h power supply unit The USB power supply unit is delivered with different electrical plug adap tors available plug types EU UK US AU Attach the suitable adapter 1 Connect the USB type A plug of the USB cable 6 02108 000 to the USB connection socket of the power supply unit 6 02117 000 2 Connect the USB type B mini plug of the USB cable 6 02108 000 to the USB connection socket 2 4 on the rear side ...

Страница 30: ...e B mini connector of the cable 6 02108 000 to the connection socket 2 4 on the rear side of the potentiostat then connect the USB type A connector of the USB cable to the PC or laptop 2 Start the Portable VA Analyzer software by double clicking the desk top icon or selecting the link Portable VA Analyzer under Windows start menu All programs Metrohm Port able VA Analyzer 3 Press the ON OFF button...

Страница 31: ... for the location of the method Click on Open to load the method The default directory for methods is USERPROFILE Docu ments Metrohm Portable VA Analyzer Method Example methods can be found in the folder USERPROFILE Documents Metrohm Portable VA Analyzer Examples Methods 3 To check or edit method parameters of the loaded method click on or Menu bar Method Edit method parameters NOTICE Some method ...

Страница 32: ...r where the method should be saved type in a file name and click on Save Loading a determination 1 Click on or on Menu bar File Load determination 2 Select the desired determination file det in the Load file dialog window If necessary browse for the location of the determination Click on Open to load the determination The default directory for determinations is USERPROFILE Documents Metrohm Portab...

Страница 33: ...e saved under the same name click on Menu bar File Save determination The existing determination file will be overwritten NOTICE Automatically saved determinations and example determinations are read only In these cases use the function Save determina tion as and save the determination under a new name 2 If a modified determination should be saved under a new name click on Menu bar File Save deter...

Страница 34: ...rresponding calibration curve can be found The subwindow Results will display the results of all substances specified in the method on the tab Results Evaluation details like peak heights and peak positions can be found in the same subwindow on the tab s Substance name At the end the determination file and if defined in the method also a PDF file with the report will automatically be saved NOTICE ...

Страница 35: ...can be freely combined by selection via check box Results General and determination information Table with concentration result for all substances in the determination Evaluation Table with evaluation details like peak potential and peak height for each substance and curve Table with regression data for each substance Curves Overlay of all voltammograms which are visible Individual calibration cur...

Страница 36: ... should be saved If necessary browse for a different directory to save the report Confirm the entries by clicking on Save The PDF file with the method parameters will be created and saved in the specified directory 5 1 4 Reevaluating a determination In this section short instructions can be found how to Adapting the peak recognition page 29 Changing the final result unit page 29 Excluding a curve ...

Страница 37: ...on 1 Click on or Menu bar Method Edit method parame ters 2 In the dialog window Method parameters go to the tab Evalua tion In the section Substances change the settings for the peak recognition e g Characteristic potential or Tolerance as required 3 Close the dialog window Method parameters with OK The determination will automatically be recalculated with the new settings Changing the final resul...

Страница 38: ... subwindow Results and select the tab with the name of the substance for which a curve should be excluded from the evaluation 2 In the column Used deactivate the check box of the curve which should be excluded from the evaluation 3 Click on or Menu bar File Reprocess to reprocess the eval uation and calculation without the excluded curve Adapting the baseline parameters for all curves 1 Click on o...

Страница 39: ... End base point 4 Click on or Menu bar File Reprocess to reprocess the eval uation and calculation with the new settings for the base point s Adapting the settings for the standard addition NOTICE The number of additions cannot be adapted subsequently However curves can be excluded from the evaluation as described above see Excluding a curve from the evaluation page 30 1 Click on or Menu bar Metho...

Страница 40: ...ution is a molar concentration e g µmol L the result unit has to be a molar concentration too e g nmol L 4 To adapt the volume of the standard addition go to the section Vol umes and adapt the addition volume of the standard solution as required NOTICE The addition volume has to be specified in mL milliliter 5 Close the dialog window Method parameters with OK The determination will automatically b...

Страница 41: ...ication Bulletin 416 NOTICE More detailed information on this application can be found in the Application Bulletin 416 Determination of arsenic in water with the scTRACE Gold which is available for download from https www metrohm com On this website also other applications using the scTRACE Gold elec trode and the 946 Portable VA Analyzer can be found 5 2 1 General operation Prepare the reagents a...

Страница 42: ...etup the hardware as described in Chapter 4 2 Hardware installation page 15 Make sure that the battery is fully charged Establish the connection between software and potentiostat as described in Chapter 4 4 Connecting the software with the instrument page 22 In daily operation the measuring head module consisting of measuring head 3 7 scTRACE Gold electrode 3 10 stirrer 3 6 and transparent ring 3 ...

Страница 43: ... 3 Use the scaling on the vessel to measure the volume 3 Position the measuring vessel on the base plate 3 1 of the measur ing stand Fit the measuring head with scTRACE Gold stirrer and transparent ring assembled in a way that electrode and stirrer immerse into the solution Press the measuring head down until the stop 4 Start the activation of the scTRACE Gold as described in Running a determinati...

Страница 44: ...RACE Gold as described in Running a determination page 25 NOTICE This method does not contain additions The determination is fin ished after 4 replications 5 When the cleaning is finished remove the measuring head with scTRACE Gold stirrer and transparent ring assembled empty the measuring vessel and thoroughly rinse electrode stirrer and vessel with ultrapure water 5 2 3 Running the determination...

Страница 45: ...on through one of the two pipetting openings in the transparent ring 3 5 using a micro pipette e g 6 01562 010 which is in the scope of delivery 8 When the determination is finished remove the measuring head with scTRACE Gold stirrer and transparent ring assembled empty the measuring vessel and thoroughly rinse electrode stirrer and vessel with ultrapure water NOTICE The example method AB416 Deter...

Страница 46: ...mple by ultrapure water but using the parameters for a sample determination If that is not sufficient carry out the cleaning procedure described in Chapter 5 2 4 Cleaning of the scTRACE Gold electrode page 38 NOTICE The scTRACE Gold electrode has a limited lifetime If the performance of the electrode cannot be recovered by the cleaning procedure descri bed in Chapter 5 2 4 Cleaning of the scTRACE ...

Страница 47: ...l to measure the volume 3 Position the measuring vessel on the base plate 3 1 of the measur ing stand Fit the measuring head with scTRACE Gold stirrer and transparent ring assembled in a way that electrode and stirrer immerse into the solution Press the measuring head down until the stop 4 Start the cleaning of the scTRACE Gold as described in Running a determination page 25 NOTICE This method doe...

Страница 48: ...ce of the electrode cannot be recovered by the cleaning procedure descri bed in the respective application description or in Chapter 5 2 4 Clean ing of the scTRACE Gold electrode page 38 the electrode needs to be replaced Indications for an outdated electrode are Significantly lower sensitivity Higher or very noisy background current Unusual peak shape Figure 13 Remove scTRACE Gold electrode 1 Rem...

Страница 49: ...are not to twist the electrode while pulling it off Tilting the elec trode may damage the contact springs of the electrode holder or the electrode itself 6 2 Removing the screen printed electrode NOTICE Screen printed electrodes can only be used for a limited number of measurements and have to be replaced in regular intervals The lifetime and the frequency of replacement depend on the type of elec...

Страница 50: ...icone seal 5 4 and the support ing ring 5 5 see Figure 14 b 4 Separate the SPE from the silicone seal and the supporting ring Discard the SPE The silicone seal and the supporting ring can be reused 5 Thoroughly dry all parts of the electrode holder NOTICE Before reassembling the electrode holder as described in chapter 4 2 3 page 16 make sure that the electrical connector for the SPE 5 2 the silic...

Страница 51: ...2 page 41 2 Remove the transparent ring 3 4 4 4 3 Unscrew the stirrer tip 6 01204 000 counterclockwise Use the 4 mm metal wrench 6 02621 000 to keep the stirrer connector from turning 6 4 Cleaning the instrument Base plate and transparent ring 1 Clean the base plate 3 1 4 1 and the transparent ring 3 4 4 4 under running water A mild dishwashing detergent can be used too NOTICE No scouring pad shou...

Страница 52: ...nto the electrical contacts scTRACE Gold electrode The cleaning and conditioning of the electrode is described in the respec tive application documentation Screen printed electrode Screen printed electrodes can only be used for a few measurements therefore usually no extensive cleaning is carried out If it is necessary the cleaning and conditioning of the electrode is described in the respective a...

Страница 53: ...nterferences are Substances producing interfering voltammetric signals such as Oxygen H2O2 other metal ions Organic compounds e g nitro compounds Anions e g nitrite sulfite Substances complexing the analyte ions such as Organic complexing agents e g EDTA humic acids etc Anions or cations forming hardly soluble salts with the analyte e g As2S3 or As2S5 Hg CN 2 Substances blocking the surface such a...

Страница 54: ... chosen in a way that the peak after the last addition is 2 5 times higher than the sample peak The sample peak and all standard addition peaks have to be within the linear working range of the method see chapter 7 4 1 page 60 7 2 Hardware problems Problem Cause Remedy Potentiostat the potentiostat cannot be connected to the software The USB cable is not con nected Connect the USB cable between po...

Страница 55: ...orms over time Replace the supporting ring when it is deformed and therefore does not equally dis tribute the pressure anymore SPE the SPE cannot be inserted into the holder The nut is already too tight and seals the slot in the sil icone seal Unfasten the nut to release pressure from the silicone seal which opens the slot for the SPE The supporting ring turned out of position Unfasten the nut and...

Страница 56: ...ic solvents are used The printed parts of the scTRACE Gold elec trode are not resistant against organic sol vents Therefore no organic solvents not even ethanol should be used for cleaning or as part of the measuring solution 7 3 Application problems Problem Cause Remedy Calibration curve the calibration curve is not displayed or calculated The peaks are not evalu ated See Peak evaluation peaks ar...

Страница 57: ... the standard addition are within the linear working range of the method see chapter 7 4 1 page 60 The peaks are not evalu ated correctly Check the baselines for all peaks and adapt the evaluation settings if necessary see Adapting the baseline parameters for all curves page 30 Adapting the base points for an individ ual curve page 31 or Excluding a curve from the evaluation page 30 Pipetting has ...

Страница 58: ...ince it can significantly change the temperature in the measuring solu tion The curves are generally not reproducible See Curve shape the curves are very noisy and Curve shape the curves show a jump a step or a flat line Calibration curve the standard addi tion is too small too big The concentration of the standard addition solution is not correct Check the standard solution used for the determina...

Страница 59: ...an affect the condi tion and sensitivity of the electrode For rec ommended storage conditions refer to the respective application documentation The electrolyte is too old Prepare a fresh electrolyte solution Also con sider the stability and age of the reagents used for the preparation The stirrer does not work correctly See Stirrer the stirrer does not rotate Curve shape the curves show a jump a s...

Страница 60: ...as recommended in the application documentation and repeat the determination If the situation does not improve replace the electrode by a new one Moisture penetrated the SPE holder Remove the SPE from the holder and thor oughly dry the electrical connection for the SPE The conductivity of the measuring solution is too low Verify the concentration of the electrolyte solu tion and the volume of elec...

Страница 61: ...ermination in a differ ent location or consider the use of a Faraday cage which is connected to earth or ground Curve shape the curves show an unusual shape The electrode surface was touched during assembly of the SPE Always hold the SPE at the edges in order to avoid contact with the electrode surface Solution penetrated the SPE holder and short cir cuits the electrodes in the connection socket D...

Страница 62: ...n ionic form and the measuring solution has to be free of inter fering substances For more details see Chap ter 7 1 2 Measuring solution page 45 Electrode is mounted in reverse position Check that the scTRACE Gold electrode see chapter 4 2 2 page 15 or the SPE see chap ter 4 2 3 page 16 is plugged in with the cor rect orientation The scTRACE Gold has an anti twist protec tion Nevertheless it is po...

Страница 63: ...rong standard addition solution Verify that the correct standard solution with the correct concentration of analyte is used Standard addition solution does not contain the ana lyte Verify that the correct standard stock solution and the appropriate volume was used for the preparation of the standard addition solution In case of doubts prepare a fresh standard addition solution Concentration and or...

Страница 64: ...parameter Characteristic potential on the tab Evaluation in accor dance with the peak position see Adapting the peak recognition page 29 Wrong evaluation parame ters The method parameters Tolerance Min width Max width and Min measured quantity on the tab Evaluation are thresh olds for the peak acceptance Check these parameters and adapt them in accordance with the peak shape Substance evaluation n...

Страница 65: ...entiostatic pretreat ment may need to be adapted The electrode was stored in water Solid state electrodes should not be stored in ultrapure water since this can affect the condi tion and sensitivity of the electrode For rec ommended storage conditions refer to the respective application documentation The electrode is too old Replace the electrode with a new one Peak position the peak in the sample...

Страница 66: ... linear work ing range of the method see chapter 7 4 1 page 60 Interference from the sam ple matrix Run a determination in standard solution to verify that the application works properly If the peak shape in standard solution is not ok clean the electrode as recommen ded in the respective application documen tation If that does not improve the situa tion replace the electrode by a new one If the p...

Страница 67: ...rs on the tab Determina tion Standard addition not cor rect See Calibration curve the calibration curve is not linear or poorly reproducible and Calibra tion curve the standard addition is too small too big Result the result is lower than expected The sample analyte is not completely dissolved The analyte has to be present in ionic form see chapter 7 1 2 page 45 If the sample cannot be completely ...

Страница 68: ...ple volume is specified in the method parameters on the tab Determina tion Standard addition not cor rect See Calibration curve the calibration curve is not linear or poorly reproducible and Calibra tion curve the standard addition is too small too big 7 4 Some voltammetric troubles in detail 7 4 1 Linear working range The quantification in voltammetric measurements is often carried out by the sta...

Страница 69: ...ygen and pH are described at the example of the scTRACE Gold electrode But similar effects can also be observed with screen printed electrodes using different electrode materi als Influence of chloride The background current of the scTRACE Gold shown in Figure 17 shows three interesting sections Section Ⓑ and Ⓒ are not affected by a change in the chloride concentration These sections are discussed...

Страница 70: ...und cur rent of the scTRACE Gold electrode Measuring solution c H2SO4 1 mmol L with 5 50 and 500 mmol L KCl c KCl 5 mmol L c KCl 50 mmol L c KCl 500 mmol L For a determination this means care has to be taken about the chloride concentration of the sample In the voltammetric parameters of the method rather positive potentials can be found in the cyclovoltammetric and potentiostatic pretreatment whi...

Страница 71: ... Table 1 Reference potential scTRACE Gold electrode against chloride concentration c KCl Potential vs Ag AgCl 3 mol L KCl Potential vs NHE 0 005 mol L 154 mV 360 mV 0 01 mol L 134 mV 340 mV 0 025 mol L 118 mV 324 mV 0 05 mol L 102 mV 308 mV 0 1 mol L 85 mV 291 mV 0 25 mol L 63 mV 269 mV 0 5 mol L 47 mV 253 mV 1 mol L 30 mV 236 mV 3 mol L 1 mV 207 mV Influence of oxygen The influence of oxygen can ...

Страница 72: ... be observed in section Ⓒ of the curve shown in Figure 19 Section Ⓑ is discussed in subchapter Influence of oxygen and section Ⓐ to a great extent in the subchapter Influence of chloride What affects the background current in section Ⓐ in slightly acid and alkaline solution in addition to what is already described for the chlor ide is the formation of Au OH 3 The big drop in the current in section...

Страница 73: ... mmol L For a determination that means that only substances which show a peak more positive than 0 5 V can be determined in an acid electrolyte At more negative potentials the current deriving from the H reduction will overlay any other analytical signal If a neutral or alkaline electrolyte can be used for the application also substances showing a peak between 0 5 V and 1 5 V can be determined ...

Страница 74: ... 20 946 Portable VA Analyzer potentiostat connected to the dummy cell 1 Dummy cell 6 02813 000 2 Potentiostat 3 Electrode cable 6 02135 000 1 Disconnect the electrode cable 6 02135 000 from the measuring stand but leave the cable connected to the potentiostat 2 Plug in the dummy cell to the female connector of the electrode cable Take care of the orientation of the plug and tighten the screw to se...

Страница 75: ...easurement The curve must be a straight line without spikes or steps At 1 0 V the current must be 0 89 1 09 µA At 1 0 V the current must be 0 89 1 09 µA To read out the exact current value at a specific potential point the cursor on the curve Below the cursor the software will display the name of the curve as well as potential and current at the specific point e g LSV_0001_sample_rep_01 1 0 0 996 ...

Страница 76: ...time 20 µs Applied potential resolution 1 mV Measured current resolution 0 025 of current range 1 pA on lowest current range Applied current resolution 0 1 of current output range Measured poten tial resolution 0 012 of potential range Potential accuracy 0 2 Current accuracy 0 5 of current range at 100 nA to 10 mA External inputs outputs Iout Eout 2 analog inputs 1 analog output 2 digital input ou...

Страница 77: ...n seal and decor strips TPE 8 2 Measuring stand Dimensions Length 116 mm Width 104 mm Height 148 mm Weight 464 g scTRACE Gold 478 g SPE Housing material Base plate and measuring head PETP Polyethyleneterephthalate Transparent ring PMMA Polymethylmethacrylate 8 3 Stirrer Stirring rate 500 4000 min 1 Accuracy 10 Stability 2 ...

Страница 78: ...he EU directives 2014 35 EC Low Voltage Directive LVD 2014 30 EC EMC Directive EMC Safety instructions This document contains safety instructions which have to be followed by the user in order to ensure safe operation of the instrument 8 6 Ambient temperature Normal function range 0 45 C at a maximum of 85 relative humidity Storage 40 70 C Transport 40 70 C 8 7 Reference conditions Ambient tempera...

Страница 79: ... 8 Technical specifications 71 8 8 Connection Connection USB version 1 1 or higher ...

Страница 80: ...ser 2 Enter the article number e g 2 946 0010 2 946 0020 into the search field The search result is displayed 3 Click on the product Detailed information regarding the product is shown on various tabs 4 On the Included parts tab click on Download the PDF The PDF file with the accessories data is created NOTICE Once you have received your new product we recommend download ing the accessories list f...

Страница 81: ...suring stand scTRACE Gold 6 Measuring stand SPE 7 Measuring vessel 6 7 Menu bar 9 10 Messages subwindow 9 12 Method Load 23 Save 24 Method menu 10 Mosaic workplace 11 N New method button 10 Nut 8 17 O O ring 6 7 ON OFF button 5 P PDF report 10 12 Peak recognition 29 Pipetting opening 6 7 26 37 Potentiostat 19 20 66 Cleaning 44 Front view 5 Rear view 5 Print Method 28 Result 27 R Reports menu 10 Re...

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