2 titration routine maintenance guide EN

Maintenance Guide Sensor Performance Titrant Performance & Standardization Day-to-Day Routine Maintenance of Automatic Titrators Content Content Introduction Instrument Installation The Effects of Temperature on the Results Sensor Performance Titrants Performance Sample Size Titrant Standarization More Information 11 12 15 Disclaimer The information contained in this guide is based on the current knowledge and experience of the authors The guide represents selected, possible application examples The experiments were conducted and the resulting data evaluated in our lab with the utmost care using the instruments specified in the description of each application The experiments were conducted and the resulting data evaluated based on our current state of knowledge.However, this guide does not absolve you from personally testing its suitability for your intended methods, instruments and purposes As the use and transfer of an application example are beyond our control, we cannot accept responsibility therefore When chemicals, solvents and gases are used, the general safety rules and the instructions given by the manufacturer or supplier must be observed METTLER TOLEDO Titration Routine Maintenance Introduction Introduction Analytical instruments need regular maintenance to ensure proper working conditions and finally correct results One part of maintenance is concerned with instrument adjustment, certification and the like Here manufacturer's service engineers are due to take actions Another part are checks which are carried out by the users or an instrument responsible person They are performed frequently, on a daily or weekly base The purpose of these checks is mainly to show whether the instrument still performs according to expectation If deviations occur, the check outcomes indicate correction measures to the users For titrators, such maintenance tasks include its installation arrangement, the influence of temperature, the sensor functionality, the titrant status and considerations regarding the sample size METTLER TOLEDO Titration Routine Maintenance Instrument Installation Instrument Installation Professional installation is fundamental to every analytical system Depending on the requirements, the right level of measures needs to be applied The measures encompass the following topics GLP International bodies have elaborated a set of rules concerning the analytical work in labs in order to achieve a standard regulation recognized and accepted in all countries of the world These rules are commonly known as GLP rules (Good Laboratory Practice) GLP is a formal framework for testing chemicals and consists of 10 specific rules Certification of an automatic titrator The certification is a check of the instrument in order to verify that the technical specifications are fulfilled, or to verify if the actual specifications meet the required level Certification is only part of a list of measures to guarantee correct results Validation of Titration Methods While the goal of the analysis is to get correct results, very often the ‘correct’ result is not necessarily the ‘true’ result As a result, our goal is in fact to get the best possible result This means a result as accurate, precise and true as possible To this it’s important to critically investigate the factors affecting each of these things and minimize the negative influences Qualification Quality management requires the documentation of the performance over the lifetime of the instrument, i.e., from the project phase through manufacturing, installation and operation through disposal of the instrument All these steps are resumed in the comprehensive concept of qualification: • Specification Qualification (SQ): Requirements, Functions, Design, HW/SW • Construction Qualification (CQ): Production control for each product • Design Qualification (DQ): Selection of correct instrument for intended use • Installation Qualification (IQ): Evidence of correct installation at customer’s facility • Operational Qualification (OQ): Evidence and compliance to specifications, SOPs, initial calibration, user training • Performance Qualification (PQ): Periodic performance tests • Maintenance Qualification (MQ): Definition of preventive maintenance and calibration/certification intervals Specially trained METTLER TOLEDO service engineers are able to perform the calibration and certification of the titrator hardware with specific calibrated and certified tools (CertiCase, Excellence Test Unit) Recommendations • Have the titration system installed by the instrument manufacturer’s specialist • Perform a General System Suitability Test, proving that the titrator is performing according to the specifications • Apply the concept of qualifications METTLER TOLEDO Titration Routine Maintenance Instrument Installation Figure 1: Lab titrator family METTLER TOLEDO Titration Routine Maintenance The Effects of Temperature on the Results The Effects of Temperature on the Results Temperature can have three different effects on a titration The first effect is related to the density, and therefore the concentration of the titrant The effect is due to the coefficient of thermal expansion This is of particular significance with non-aqueous titrants where the coefficient of thermal expansion is much higher than with deionized water Below is a table showing typical errors The second becomes apparent when performing an endpoint titration to a predefined pH value The pH of the sample depends on the degree of dissociation of the acids and bases present The dissociation is temperature dependent Thus, a temperature change gives rise to a real change in the pH value This change cannot be accounted for without knowing the sample’s exact composition A further effect concerns the actual measurement process and the slope of the electrode calibration curve The slope of the calibration curve is temperature dependent so it is important to either perform the analysis at the same temperature at which the electrode was adjusted, or to measure both temperatures and compensate for the change in slope of the calibration curve Fortunately, most modern instruments are able to simultaneously measure the sample temperature and automatically compensate for this error Titrant % Error per °C change 0.1 M NaOH 0.027 M NaOH 0.036 0.1 M HCl 0.026 M HCl 0.029 component mg/mL Karl Fischer Reagent 0.092 Table 1: Error in concentration due to temperature change Recommendations • The best solution is to maintain constant temperature in the laboratory e.g by air condition Air condition prevents temperature shifts • Keep samples in the same place as titrants to ensure the same termperature If the titrant concentration (i.e titer determination) and samples are measured at the same temperature then there is no error • Do not expose the instrument to direct sunlight Place it in a protected area • Measure the temperature when performing pH measurements or end point titrations - METTLER TOLEDO offers pH sensors with integrated temperature probes for this purpose • Use certified pH buffers for sensor calibration and apply their temperature table - METTLER TOLEDO titrators and pH meters automatically offer this possibility • Perform titrant standardization when the temperature changes significantly Re-standardizing reduces errors due to temperature changes considerably Apply a temperature correction factor: Measure the temperature of the titrant and correct for the temperataure change Example: Karl Fischer reagent, 10°C temperature difference in the lab f = + (Ttiter – Tsample) x CONC-ERR CON C-ERR = 0.092 / 100 = 0.00092 TT – TS = -10 f = – 10 x 0.00092 = 0.9908 Multiplying raw results by this factor will account for the error METTLER TOLEDO Titration Routine Maintenance Sensor Performance Sensor Performance In pH endpoint titrations, critical factors affecting result accuracy are the slope and zero point of the sensor Both of these parameters are used to convert the raw mV signal from the sensor into the pH of the sample solution using the Nernst equation: pH = pHo – E S E S pH0 , where = measured signal (in mV) = sensor slope = – 2.3 RT / nF = sensor zero point = E0/S Since sensors are the actual ‘measurement devices’, they have a very large influence on the result of any titration Several factors contribute to their behaviour: Response: If a sensor is sluggish because of old age or bad maintenance, the mV reading detected by the sensor will lag behind the ‘true’ value Calibration: Sensor calibration is particularly important for endpoint titrations (mainly pH endpoints) The accuracy of the measured value is directly related to the determined amount of the analyte content in the sample Every maintenance procedure performed on a sensor (cleaning, regeneration, etc.), requires that the sensor be calibrated again For pH, we recommend to apply a two or three point calibration If samples are usually around 7, three calibration points at pH 4, and (or 10) are good practice This ensures that pH values below and above are measured correctly If the samples are acidic, a two point calibration between and is usually acceptable and yields reliable results mV real pH ideal Figure 2: Schematic of a three-point pH calibration Reference electrode: A reference electrode has to provide a stable reference signal against which the measurement signal is determined Conditioning: The measuring membrane of any pH or ion selective electrode needs to be conditioned before the sensor can be used METTLER TOLEDO Titration Routine Maintenance Sensor Performance When a pH sensor is used in non-aqueous media, the sensor needs to be conditioned before its next use to restore the hydration layer Recommendations • Define a sensor calibration frequency to make sure that the sensor is measuring correctly, e.g at least once per day • Instead of frequent calibrations, a sensor check can be performed Such a check shows that the sensor is still functioning correctly but it does not change calibration data The sensor check should include the signal drift over one minute, which is an important indication of the response time and signal stability Use pH buffer or as a sample for this check • Take the appropriate measures to automatically remind users to calibrate - METTLER TOLEDO Excellence titrators offer the functionality of monitoring sensors’ life span as well as usable life When a calibration needs to be performed or the sensor needs replacing, the user is automatically reminded A sensor can even be blocked from use if the setting is chosen accordingly • Define acceptance limits for the calibration results - All METTLER TOLEDO titrators allow these limits to be set in the method If the limit is exceeded, the user is prompted and the calibration data is not saved • When not in use, sensors should be stored in electrolyte Figure 3: Details of the measuring membrane of pH electrodes METTLER TOLEDO Titration Routine Maintenance Titrants Performance Titrants Performance The concentration of a titrant needs to be known accurately to be able to determine the content of analyte in the sample solution If the titrant concentration is unknown or inaccurate, there will inevitably be a degree of error Titer From the determined titrant concentration and the nominal titrant concentration, a titer value t is calculated The titer is the ratio of ‘determined concentration / nominal concentration’ and is generally close to t = current titrant concentration / nominal titrant concentration Example: Current titrant concentration, by determination: 0.1036 mol/L Nominal titrant concentration, by declaration: 0.1 mol/L Titer t = 0.1036 / 0.1 = 1.036 For titer determinations, a primary standard is preferable A primary standard is a substance that reacts with the titrant in a known ratio ("stoichimetrically") Its purity is high and well defined It is very stable and has a high molecular weight Examples of primary standards: Tris-hydroxy amino methane (THAM) for acids, Potassium hydrogen phthalate (KHP) for bases, NaCl or KCl for argentometry Titrant life time Titrants can deteriorate over time through various external influences like oxidation, precipitation, carbon dioxide absorption or UV degradation We can account for some of these by using drying tubes filled with NaOH on carrier material (CO2 absorption in alkaline titrants) or with brown bottles (light protection) The rate of deterioration determines how long the titrant can be used before re-standardizing This is called the “usable life’ of the titrant After the usable life has expired, a new titer determination should be performed before running subsequent analyses In most titrators, the usable life of a specific titrant can be defined and standardization intervals can be enforced before being allowed to continue The lifespan of a titrant is the time after which a titrant should be replaced The lifespan is different for every type of titrant For example, acids are more stable than alkaline titrants and can have a life span of up to a year, compared to months for a base During the lifespan, regular standardization should be performed to guarantee reliable results Recommendations • Define a standardization frequency ensuring titrant concentration (titer t) is correct • Define a titrant life span • Take the appropriate measures to automatically remind users to perform a standardization, preventing usage of a titrant with an exceeded usable life - METTLER TOLEDO Excellence titrators offer the functionality of monitoring titrants, automatically warn and remind users and block unfit titrants from use • Define acceptance limits for the titer determination, e.g 0.96 ≤ t ≤ 1.05 - All METTLER TOLEDO titrators allow these limits to be set in the standardization method If the limit is exceeded, the user is prompted and the new titer value will not be saved • Prepare and store titrants with care METTLER TOLEDO Titration Routine Maintenance Titrants Performance • In the case of alkaline titrants such as sodium and potassium hydroxide, it’s important that they are prepared with water or solvent free of carbon dioxide, and that they are protected from atmospheric exposure to carbon dioxide Attach a drying tube containing an absorbent (e.g NaOH on a granular carrier) to the titrant bottle • Titrants such as iodine, permanganate and dichromate are light sensitive and need to be protected by storing them in brown glass bottles Karl Fischer reagents need to be protected from light as well as from the ingress of atmospheric humidity This is done by attaching a drying tube containing silica gel or molecular sieve to the titrant bottle Figure 4: Automatic titrator with titrants (burettes) METTLER TOLEDO Titration Routine Maintenance 10 Sample Size Sample Size By far, the biggest source of random errors resulting in precision problems is sample handling These errors include inhomogeneity of the sample, sample storage problems, incorrect sample size, weighing errors, and careless handling Critical in most cases is the sample size The sample should be large enough to ensure that it is representative, but it shouldn’t be so large that repeated burette fillings are necessary during the titration The ideal sample size should give a titrant consumption of 30 to 80% of a single burette volume On the other extreme, the sample should be large enough so that weighing or sample measuring errors are kept to a minimum Here, a suitable balance must be used to ensure that the sample size exceeds the minimum weight of the balance This minimum weight is defined as the weight which when measured tenfold, results in a repeatability of less than a certain pre-defined value; for example, United States Pharmacopoeia (USP) states a value of less than 0.1% The sample volume including deionized water and/or other solvents that is used for any titration should be sufficient to cover the sensor’s active parts (junction and sensing membrane or metal ring) Normally, this volume should be around 50 mL to be able to fit the stirrer, titration tubes and dosing tubes in with the probe For smaller sample sizes, special micro-titration beakers can be used Recommendations • Make sure that you're using the needed balance resolution for your sample size The accuracy and precision of the sample size must be smaller than the expected accuracy and precision of the titration result • For solid samples, use a calibrated analytical balance with 0.1 mg or 0.01 mg readability • For liquid samples use a calibrated high quality Rainin® pipette • Choose a sample size that consumes 30 to 80% of the burette’s volume The sample size, titrant concentration or burette size can be changed to reach this goal • Dilute the sample with an appropriate solvent volume to make sure the active parts of the equipment are covered (approximately 50 mL) If necessary, use micro-titration equipment METTLER TOLEDO Titration Routine Maintenance 11 Titrant Standardization Overview Titrant Standardization Overview Solvent and Auxiliary reagents Frequence of Standarization Protection of Titrant / General Remarks DG111SC Deion H2O weekly Protect from CO2 (absorption tube filled with NaOH on carrier granulate) M002 DG111SC Deion H2O weekly Protect from CO2 (absorption tube filled with NaOH on carrier granulate) Benzoic acid C7H6O2; M = 122.12 M010 DG115SC LiCl 1M in EtOH Isopropanol weekly Protect from CO2 (absorption tube filled with NaOH on carrier granulate) Sodium methylate Benzoic acid c(NaOCH3) = C7H6O2; M = 0.1 mol/L 122.12 M026 DG115SC LiCl 1M in EtOH Methanol daily Protect from CO2 (absorption tube filled with NaOH on carrier granulate) Potassium hydroxide c(KOH) = 0.1 mol/L Benzoic acid C7H6O2; M = 122.12 M027 DG115SC LiCl 1M in EtOH Ethanol weekly Protect from CO2 (absorption tube filled with NaOH on carrier granulate) Sulfuric acid c(1/2 H2SO4) = 0.1 mol/L Tris(hydroxymethyl)aminomethane [THAM] C4H11NO3; M = 121.14 g/mol M011 DG111SC Deion H2O every weeks Hydrochloric acid c(HCl) = 0.1 mol/L Tris(hydroxymethyl)aminomethane [THAM] C4H11NO3; M = 121.14 g/mol M003 DG111SC Deion H2O every weeks Perchloric acid c(HClO4) = 0.1 mol/L Tris(hydroxymethyl)aminomethane [THAM] C4H11NO3; M = 121.14 g/mol M005 DG115SC LiCl 1M in EtOH Acetic acid weekly Titrant Standard Substance Method Indication Sodium hydroxide Potassium c(NaOH) = 1.0 hydrogen mol/L phthalate C8H5KO4; M = 204.23 M025 Sodium hydroxide Potassium c(NaOH) = 0.1 hydrogen mol/L phthalate C8H5KO4; M = 204.23 Tetrabutyl ammonium hydroxide c(TBAH) = 0.1 mol/L Alkalimetry Acidimetry Table 2: Alkalimetric and acidimetric titrants METTLER TOLEDO Titration Routine Maintenance 12 Titrant Standardization Overview Titrant Frequence of Standarization Protection of Titrant / General Remarks DM141- Deion H2O SC acidify to pH 3.5 every weeks Keep bottle in dark M028 DM141- Deion H2O SC acidify to pH 3.5 every weeks M024 DP550 Deion H2O Buffer pH Thorin weekly Standard Substance Method Indication Silver nitrate c(AgNO3) = 0.1 mol/L Sodium chloride NaCl; M = 58.44 M006 Sodium chloride c(NaCl) = 0.1 mol/L Silver nitrate AgNO3; M=169.89 Barium chloride c(BaCl2) = 0.1 mol/L Sodium sulfate Na2SO4; M = 142.05 Solvent and Auxiliary reagents Precipitation Complexometry Complexone III c(EDTA) = 0.1 mol/L Zink sulfate ZnSO4; M = 161.44 M007 DP660 Deion H2O Buffer pH 10,5 Indicator Erio T every weeks Use PE bottles Complexone III c(EDTA) = 0.1 mol/L Calcium carbonate CaCO3; M = 100.09 M022 DP660 Deion H2O Indicator buffer tablet MERCK every weeks Use PE bottles Complexone VI c(EGTA) = 0.1 mol/L Calcium carbonate CaCO3; M = 100.09 M014 DP660 Deion H2O Indicator buffer tablet MERCK every weeks Use PE bottles Zink sulfate c(ZnSO4) = 0.1 mol/L EDTA 2H2O EDTA ; M=372.24 M029 DP660 Deion H2O Buffer pH 10,5 Indicator Erio T every weeks Use PE bottles Barium perchlorate c(Ba(ClO4)2) = 0.005 mol/L EDTA 2H2O EDTA ; M=372.24 M023 DP550 Deion H2O / methanol NH3 solution 5% Indicator Phthaleinpurpur weekly Use PE bottles Table 3: Precipitation and complexometric titrants METTLER TOLEDO Titration Routine Maintenance 13 Titrant Standardization Overview Titrant Standard Substance Method Indication Solvent and Auxiliary reagents Frequence of Standarization Protection of Titrant / General Remarks Redox – Titration (Reducing titrants) Sodium thiosulfate c(Na2S2O3) = 0.1 mol/L Potassium iodate KIO3; M = 214.00 g/mol M009 DM140-SC Hydrochloric acid 0.1 M every weeks Hydroquinone c(C6H6O2)= 0.1 mol/L Potassium dichromate K2Cr2O7; M = 294.19 g/mol M017 DM140-SC Sulfuric acid 5% weekly Keep bottle in dark Ammonium ferrous (II) sulfate c(FAS) = 0.1 mol/L Potassium dichromate K2Cr2O7; M = 294.19 g/mol M008 DM140-SC Sulfuric acid 5% daily Protect from Oxygen Redox – Titration (Oxidizing titrants) Iron(III) chloride c(FeCl3) = 0.1 mol/L Ascorbic acid C6H8O6; M = 176.13 g/mol M030 DM140-SC Deion H2O every weeks Potassium dichromate c(1/6 K2Cr2O7) = 0.1 mol/L (CH2NH3)2SO4 ∙ FeSO4 ∙ 4H2O M = 382.15 M031 DM140-SC Sulfuric acid 5% every weeks Iodine c(1/2 I2) = 0.1 mol/L di-Arsenic trioxide As2O3; M = 197.84 g/mol M016 DM140-SC DG111-SC Deion H2O NaHCO3 daily Cerium sulfate c(Ce(SO4)2) = 0.1 mol/L di-Sodium oxalate C2Na2O4; M=134.00 g/mol M015 DG140-SC Deion H2O Sulfuric acid 5% every weeks Potassium permanganate c(1/5 KMnO4) = 0.1 mol/L di-Sodium oxalate C2Na2O4; M=134.00 g/mol M013 DG140-SC Sulfuric acid 5% 70 °C every weeks Sodium nitrite c(NaNO2) = 0.1 mol/L Sulfanilic acid C6H7NO3S; M = 173.19 g/mol M032 DM140-SC HBr 0,5 mol/L weekly Fehling solution Glucose 1% in water C6H12O6; M = 180.16 g/mol M033 Combi Pt-ring (Ingold) Deion H2O weekly Prepare Glucose solution daily 2,6-Dichlorophenolindophenol Na- salt c(DPI) = 0.01 mol/L Ascorbic acid C6H8O6; M = 176.13 g/mol M021 DM142 mit DK102 Deion H2O daily Keep bottle in dark Keep in PE bottles Keep cool Keep bottle in dark Keep cool Keep bottle in dark Table 4: Redox titrants Titrant Standard Substance Method Indication Solvent and Auxiliary reagents Frequence of Standarization Protection of Titrant / General Remarks Turbidimetric Titrations Sodium dodecylsulfate c(SDS) = 0.01 mol/L N-Cetylpyridinium chloride [CPC] M = 358.01 g/mol M035 DP550 Deion H2O every weeks Rinse bottle and beakers with deion water before use Hyamine c(Hyamine) = 0.01 mol/L Sodium dodecylsulfate [SDS]; M = 288.4 g/mol M036 DP550 Deion H2O every weeks Rinse bottle and beakers with deion water before use N-Cetylpyridinium chloride c(CPC) = 0.01 mol/L Sodium dodecylsulfate [SDS]; M = 288.4 g/mol M012 DP660 Deion H2O every weeks Rinse bottle and beakers with deion water before use Table 5: Turbidimetric Titrations METTLER TOLEDO Titration Routine Maintenance 14 More Information More Information 7.1 Brochures GTP Risk Checker, Mettler-Toledo Analytical, 10/2010 Validation of Titration Methods, Application Brochure 16, Mettler-Toledo Analytical, 03/2015, 51724912A 7.2 Webinars We provide web-based seminars (webinars) on different topics You can participate in on-demand webinars at any convenient time and place Live webinars offer the added benefit of allowing you to ask questions and discuss points of interest with METTLER TOLEDO specialists and other participants www.mt.com/webinars 7.3 Applications and UserComs We offer comprehensive titration application support Titration applications www.mt.com/titration_applications Titration UserCom www.mt.com/anachem-usercom 7.4 Product News Visit our titration landing page to get informed about the latest product news www.mt.com/Titration 7.5 Lab Library The Lab Library is a one-stop portal to access knowledge resources such as webinars, literature, product info and much more www.mt.com/Lab-Library METTLER TOLEDO Titration Routine Maintenance 15 Good Titration Practice™ Five Steps to Improved Results GTP® – Good Titration Practice™ Dependable Titration in Practice – Reliable Results with GTP A requirementsbased selection of the titration system, as well as professional installation and training form the basis for dependable and risk-free titration GTP reduces the risks associated with titration and facilitates • compliance with regulations • preservation of the accuracy and precision of results • increased productivity and reduced costs • professional qualification and training www.mt.com/gtp Routine Operation Calibration / Qualification Evaluation Good Measuring Practices Selection Installation / Training More Good Measuring Practices Other Good Measuring Practices are available for weighing, pipetting, density and refractive index determination, thermal analysis, melting and dropping point determination as well as pH, conductivity, dissolved oxygen and redox measurements www.mt.com/gp www.mt.com For more information Mettler-Toledo Intenational Inc Laboratory Division CH-8606 Greifensee, Switzerland Subject to technical changes © 06/2015 Mettler-Toledo AG Global MarCom Switzerland / MC [...]... Deion H2O every 2 weeks Potassium dichromate c(1/6 K2Cr2O7) = 0.1 mol/L (CH2NH3)2SO4 ∙ FeSO4 ∙ 4H2O M = 3 82. 15 M031 DM140-SC Sulfuric acid 5% every 2 weeks Iodine c(1 /2 I2) = 0.1 mol/L di-Arsenic trioxide As2O3; M = 197.84 g/mol M016 DM140-SC DG111-SC Deion H2O NaHCO3 daily Cerium sulfate c(Ce(SO4 )2) = 0.1 mol/L di-Sodium oxalate C2Na2O4; M=134.00 g/mol M015 DG140-SC Deion H2O Sulfuric acid 5% every 2 weeks... Calcium carbonate CaCO3; M = 100.09 M014 DP660 Deion H2O Indicator buffer tablet MERCK every 2 weeks Use PE bottles Zink sulfate c(ZnSO4) = 0.1 mol/L EDTA 2H2O EDTA ; M=3 72. 24 M 029 DP660 Deion H2O Buffer pH 10,5 Indicator Erio T every 2 weeks Use PE bottles Barium perchlorate c(Ba(ClO4 )2) = 0.005 mol/L EDTA 2H2O EDTA ; M=3 72. 24 M 023 DP550 Deion H2O / methanol NH3 solution 5% Indicator Phthaleinpurpur... M0 02 DG111SC Deion H2O weekly Protect from CO2 (absorption tube filled with NaOH on carrier granulate) Benzoic acid C7H6O2; M = 122 . 12 M010 DG115SC LiCl 1M in EtOH Isopropanol weekly Protect from CO2 (absorption tube filled with NaOH on carrier granulate) Sodium methylate Benzoic acid c(NaOCH3) = C7H6O2; M = 0.1 mol/L 122 . 12 M 026 DG115SC LiCl 1M in EtOH Methanol daily Protect from CO2 (absorption tube... Alkalimetry Acidimetry Table 2: Alkalimetric and acidimetric titrants METTLER TOLEDO Titration Routine Maintenance 12 Titrant Standardization Overview Titrant Frequence of Standarization Protection of Titrant / General Remarks DM141- Deion H2O SC acidify to pH 3.5 every 2 weeks Keep bottle in dark M 028 DM141- Deion H2O SC acidify to pH 3.5 every 2 weeks M 024 DP550 Deion H2O Buffer pH 4 Thorin weekly... equipment are covered (approximately 50 mL) If necessary, use micro -titration equipment METTLER TOLEDO Titration Routine Maintenance 11 Titrant Standardization Overview 7 Titrant Standardization Overview Solvent and Auxiliary reagents Frequence of Standarization Protection of Titrant / General Remarks DG111SC Deion H2O weekly Protect from CO2 (absorption tube filled with NaOH on carrier granulate) M0 02. .. Turbidimetric Titrations METTLER TOLEDO Titration Routine Maintenance 14 More Information 8 More Information 7.1 Brochures GTP Risk Checker, Mettler-Toledo Analytical, 10 /20 10 Validation of Titration Methods, Application Brochure 16, Mettler-Toledo Analytical, 03 /20 15, 51 724 912A 7 .2 Webinars We provide web-based seminars (webinars) on different topics You can participate in on-demand webinars at any convenient... 0.1 mol/L Benzoic acid C7H6O2; M = 122 . 12 M 027 DG115SC LiCl 1M in EtOH Ethanol weekly Protect from CO2 (absorption tube filled with NaOH on carrier granulate) Sulfuric acid c(1 /2 H2SO4) = 0.1 mol/L Tris(hydroxymethyl)aminomethane [THAM] C4H11NO3; M = 121 .14 g/mol M011 DG111SC Deion H2O every 2 weeks Hydrochloric acid c(HCl) = 0.1 mol/L Tris(hydroxymethyl)aminomethane [THAM] C4H11NO3; M = 121 .14 g/mol... METTLER TOLEDO Titration Routine Maintenance 13 Titrant Standardization Overview Titrant Standard Substance Method Indication Solvent and Auxiliary reagents Frequence of Standarization Protection of Titrant / General Remarks Redox – Titration (Reducing titrants) Sodium thiosulfate c(Na2S2O3) = 0.1 mol/L Potassium iodate KIO3; M = 21 4.00 g/mol M009 DM140-SC Hydrochloric acid 0.1 M every 2 weeks Hydroquinone... chloride c(BaCl2) = 0.1 mol/L Sodium sulfate Na2SO4; M = 1 42. 05 Solvent and Auxiliary reagents Precipitation Complexometry Complexone III c(EDTA) = 0.1 mol/L Zink sulfate ZnSO4; M = 161.44 M007 DP660 Deion H2O Buffer pH 10,5 Indicator Erio T every 2 weeks Use PE bottles Complexone III c(EDTA) = 0.1 mol/L Calcium carbonate CaCO3; M = 100.09 M 022 DP660 Deion H2O Indicator buffer tablet MERCK every 2 weeks Use... mol/L di-Sodium oxalate C2Na2O4; M=134.00 g/mol M013 DG140-SC Sulfuric acid 5% 70 °C every 2 weeks Sodium nitrite c(NaNO2) = 0.1 mol/L Sulfanilic acid C6H7NO3S; M = 173.19 g/mol M0 32 DM140-SC HBr 0,5 mol/L weekly Fehling solution Glucose 1% in water C6H12O6; M = 180.16 g/mol M033 Combi Pt-ring (Ingold) Deion H2O weekly Prepare Glucose solution daily 2, 6-Dichlorophenolindophenol Na- salt c(DPI) = 0.01 ... Deion H2O every weeks Potassium dichromate c(1/6 K2Cr2O7) = 0.1 mol/L (CH2NH3)2SO4 ∙ FeSO4 ∙ 4H2O M = 3 82. 15 M031 DM140-SC Sulfuric acid 5% every weeks Iodine c(1 /2 I2) = 0.1 mol/L di-Arsenic trioxide... METTLER TOLEDO Titration Routine Maintenance Sensor Performance Sensor Performance In pH endpoint titrations, critical factors affecting result accuracy are the slope and zero point of the sensor Both... to be conditioned before the sensor can be used METTLER TOLEDO Titration Routine Maintenance Sensor Performance When a pH sensor is used in non-aqueous media, the sensor needs to be conditioned