UserCom1

USER COM Spring 1998 1

USER COMSpring 1998

1Dear readerOur aim with this new customermagazine is to offer you evenbetter service.In the section DL-TIP we pro-vide you with tips and advicebased on our years of practicalexperience.You will also find information onnew products and their use, aswell as applications from allfields of titration and electro-chemistry.

We wish you an enjoyable read !

Contents

DL TIP- Standardization of Titrants

How is it done ? How frequently ?What precautions are needed ?

NEW in the sales program- DLBase

New database software for DL50and DL70 Titrators

- MPC227 ConductometerSpecially for conductivity titration

Accessories- A large assortment for titration

An overview

Applications- Memory Card application package

Methods on memory card- Titration in the Petroleum Industry

Determine key values for qualityquickly and precisely

- New Vitamin C determinationRevolutionary amperometric indication

IntroductionThe history of volumetric analysis can be traced back to the work ofLavoisier and his contemporaries in the 18th century. The first titrationswere performed in those days, initially with solid reagents (e.g. potash) butsoon after with so-called standard solutions of known concentration.

A titration determines how much standard solution is needed to react withthe entire amount of substance in the sample. The analyte concentration canbe calculated using the consumption, the titrant concentration in mol/L andthe molar mass M. It should be noted that titration is not an absolutemethod as the result is decisively influenced by the titrant concentration.

The effective titrant concentration normally differs from the nominal con-centration owing either to inaccurate preparation or changes due to thechemical stability.

How is the titer determined ?The determination of the effective concentration, generally called titer de-termination is through titration of a substance of exactly known concentra-tion. Whenever possible, primary standards are used. These are chemicalswhich meet the following conditions [1, 2, 3, 4]:

• Clearly defined composition and high purity• High molar mass (to avoid weighing errors)• Easy to dry• Can be weighed without any difficulties (no reaction with oxygen or CO

2,

not hygroscopic)• Quickly and readily soluble in the solvent used• Rapid and stoichiometric reaction with the titrant.

Standardizationof Titrants

Information for users ofMETTLER TOLEDO Titration and pH Systems

DL-TIP

2 USER COM Spring 1998

METTLER TOLEDO DL55 Titrator

In practice, there are very few idealsubstances which meet all these con-ditions. For example, sodium carbon-ate is hygroscopic and must be driedagain before use [2].

In cases in which no suitable primarystandard can be found, a so-calledsecondary standard can be used, inother words a chemical whose exactcomposition is known through com-parison with a primary standard [4].

How frequently should the titerbe determined?It is essential to standardize all ti-trants which are used for the firsttime. This also applies to purchas-able reagents of guaranteed accu-racy, as not only concentration er-rors but also burette inaccuracies arecompensated in the titer factor. (Ifcorrosive reagents such as sodiumhydroxide are used, the burette di-ameter may change.)

Depending on the stability of the ti-trant used, the titer should be deter-mined more or less frequently.Table 1 shows a few examples offrequently used titrants.In this connection, it is interestingto note that the new DL50 Titrators(see Figure 1) from METTLERTOLEDO allow the titer determina-tion interval to be programmed: theinstrument informs the user when adetermination has to be performed.This naturally leads to improved ac-curacy of the results.

MethodologyThe METTLER TOLEDOapplication brochures 8, 9and 18 contain the method-ology, results and tips onthe titer determination ofthe most frequently used ti-trants in acidimetry and al-kalimetry, redox titrations,complexometric, turbimetricand precipitation titrations.As a selection of titer deter-mination methods is storedin every instrument, themost common determina-tions can be started at a key-stroke.

Important pointsIt must be emphaticallypointed out that the titermust be determined withparticular care [3]. Each error actsas a systematic error in all determi-nations which are performed withthe particular standard solution. Ti-ter determinations should always in-volve multiple determinations andbe statistically evaluated. The use ofa mathematical test to detect outli-ers (e.g. Grubbs) is advisable [1].Professional instruments such as theDL70 Titrators from METTLERTOLEDO allow automatic perfor-mance of this test after every series.Titer determinations are also emi-nently suitable for system suitabilitytests and quickly provide informa-tion on whether the system used isstill suitable [5].

Titrant Standard substance Frequency Comments

Sodium hydroxide Potassium hydro- weekly Protect against theNaOH genphthalate ingress of CO2

Sulfuric acid Tris(hydroxymethyl) every 14 daysH2SO4 aminomethane

Dichlorophenol- Ascorbic acid daily Store in a coolindophenol (Vitamin C) and dark place

Karl Fischer reagent Sodium tartrate daily Protect againstComposite 5 dihydrate moisture

Table 1: Primary titrant standards

References

[1] METTLER TOLEDO, Funda-mentals of Titration, 1993

[2] Vogel, Textbook of quantitativeinorganic analysis, 4th edition,1978

[3] Jander•Jahr, Massanalyse,14. Auflage, de Gruyter, 1986

[4] E. Merck, Primary VolumetricStandards

[5] METTLER TOLEDOApplications Brochure 15,Guidelines for Result Check,Method Validation and Instru-ment Certification


DLBase – the Database Applicationfor DLWin

Archiving and retrieving data and results is of increasing importance inan age of constantly growing amount of information. Data have to beprocessed, they have to be presented to other people in an easily under-standable manner and they have to be checked for plausibility. Taskslike these call for a specialized tool that manages data in a database.This is the only way to ensure data integrity.

As of now these customer wishescan be realized with DLBase, anewly introduced software thatcomplements DLWin, enabling thedata stored in DLWin to be man-aged. Listed below are the possibili-ties that DLBase offers.

Different search criteriaData can be sorted using items suchas method ID and version, user, dateand time. This makes retrieval ofcertain data possible.

Filter functionsFilter functions allow for excludingcertain items from being displayed.Criteria such as method ID or se-ries No. may be used for filtering.This makes data representationclearer.

Definition of SOPsWith this option it is possible to en-ter certain limits that define the va-lidity of results. A freely definableSOP text serves for explanation.

Data overviewGives an overview of results, elec-trodes, titrants and other data.

Statistic functionsResults are arranged clearly withtheir statistics. Taking the SOPs intoaccount, results are excluded fromthe statistics calculation (see figurebelow).

Export and print functionsAll data can either be printed in aclear presentation or exported toExcel with one mouse click.

The statistics function enables mean values and standard deviations to becalculated, and makes it possible to verify graphically that the results arewithin set limits.DLBase offers all the functions that are necessary to deal with largeamounts of data. This is achieved by intuitive and easy operation.

NEW in the sales program


MPC227 – the New CombinedpH /Conductivity Meter

Several with one blow! Or how to kill two birds with one stone.METTLER TOLEDO breaks new ground with the launch of the firstcombined pH/conductivity meter, the MPC227.

One of the greatest challenges in thechemistry lab today is quality assur-ance and the associated tasks to ful-fill the legal regulations. Completedocumentation is just as much amust as strict adherence to the stan-dard operating procedures. TheMPC227 reminds the user after acertain time interval that calibrationis required, it stores the results ofthe last calibration, automaticallyshows the quality of the electrodeand provides full documentation ofthe measurement results on a dotmatrix printer. GLP requirementsare thus met effortlessly.

Three different conductivity sensorsare available so that measurementsin the range 0 – 1000 mS can al-ways be performed with a suitablesensor and corrosive media can al-ways be “handled” without any

problems. One sensor is also par-ticularly suitable for conductometrictitrations.

Combination Titrator/MPC227A connection from the conductivitymeter to the titrator is available fortwo extremely interesting applica-tions:

• Automated direct measurement ofthe conductivity in combinationwith other analyses, e.g. in thewater industry (calcium, chloride,alkalinity, fluoride).

• Conductometric indication of ti-trations as an alternative topotentiometry.

Thanks to the calibrated and switch-able analog output, the MPC227forms an excellent combinationwith the DL50 and DL70 Titratorsfrom METTLER TOLEDO. A spe-cial logarithmic data transfer en-sures equally high accuracy over theentire measurement range.

With the MPC227 the user pur-chases a quality instrument fortrouble-free measurement of pH-values and conductivity. The com-bined instrument saves space andcosts, particularly in frequent mea-surements of one parameter and oc-casional measurements of the otherparameter.

Titration users and water analystswill appreciate the combination ofthe two instruments as an interest-ing new feature in the METTLERTOLEDO range. The MPC227 willbe available from mid 1998.

Many customers have to measurepH and conductivity. For example,in the water and waste water indus-try both parameters are importantcharacteristics for the water qual-ity.

Where separate instruments wereneeded previously, the MPC227works for two, which naturally low-ers the capital outlay and savesvaluable lab bench space.

The two independent measurementchannels can be calibrated simplyand conveniently with pH or con-ductivity standards, with the instru-ment accepting any order of thecalibration solutions thanks to theautomatic buffer recognition. Athree-point calibration for the pHchannel assures high result accu-racy.

Combination of DL55 Titrator / MPC227 pH/Conductivity Meter / GA42 Printer

NEW in the sales program


Powerful Analitics due to the RightOptional Equipment

Automation

Prepare and transport samples orprocess different determinations un-supervised in succession: needswhich can be satisfied with theST20A Sample Changer. Up to 20samples can be analyzed one afterthe other, the titration stand is rinsedbetween samples and the electrodeconditioned.

There is now a wide range of optional equipment available for thetitrators from METTLER TOLEDO. Depending on the application,suitable accessories can improve the result accuracy, reduce the labourinvolved or open up the way to new applications.

Cleaning

To avoid carryover of the sample,the titration stand should be care-fully rinsed after every analysis.This is facilitated by use of a rinsingunit. A simple press is all that isneeded to ensure the titration standis clean and ready for the next deter-mination.

Application brochures

Method development can be timeconsuming. The choice of suitableconditions, procedures and calcula-tions often requires tedious experi-ments. METTLER TOLEDO makesits know-how and experience avail-able in the form of detailed applica-tion brochures. These offer meth-ods, results, curves and also tips andtricks, for example on samplepreparation or disposal.

Accessories


KF accessories

The DV705 Karl-Fischer Standchanges a potentiometric titratorinto an instrument for water deter-mination. Drying ovens permitKarl-Fischer titrations of sampleswhich are difficult to access.

Beakers

Naturally also various beakers(glass, plastic, 100 mL, 250 mL,thermostatable) are available, as aresuitable stoppers, weighing boats,drying tubes, burettes, cables andprinters.

Sensors

The titration electrodes fromMETTLER TOLEDO prove theirworth in harsh routine use. The ser-vice life of the electrode dependsgreatly on choosing the right elec-trode. The sleeve models in particu-lar are distinguished by exceptionalruggedness and a fast response time.A speciality are the phototrodes, ac-tual photometers which measure thelight absorption in the sample andthus allow automatic color changetitrations.

Sensor Type Frit Application

DG101-SC pH Ceramic Micro applicationsDG111-SC pH Ceramic Standard acid/baseDG113-SC pH Sleeve, movable Nonaqueous titrations, TAN/TBNDG114-SC pH Sleeve, movable Turbid, contaminated samples, proteinsDG115-SC pH Sleeve, fixed Low ionic strength, rapid reactionDM140-SC Pt Ceramic Redox titrations (Cer, KMnO4, I2)DM141-SC Ag Ceramic Precipitation titrations (AgNO3)DM142 Pt — Voltametry (KF, VitC)DP550 Photo — Photometric titration (Ca/Mg, surfactants)DP660 Photo — Photometric titration (Al, Cu)

Overview of the sensors


Insert MemoryCard – Load Method– Start Titration

Taking the memory card applicationpackage for beverage industry deter-minations as example provides anoverview of the information that theuser can expect from this type ofdata storage.

16 methods are stored on thememory card for beverage determi-nations, the applications rangingfrom the combined determination ofpH and acid number in fruit juicesthrough the sulfur dioxide contentof red and white wines to the deter-mination of reducing sugars in wineand juices. For vitamin C determi-nation both the amperometric andthe voltametric methods are de-scribed, together with their advan-tages and disadvantages. The sulfatecontent in mineral water can be de-

termined with the help of a barium-selective electrode.Instructions for preparing the sampleand notes on the measurements car-ried out in the application lab sim-plify the use of the methods in prac-tice.Nowadays time is at a premium inthe laboratory. When using thememory card unnecessary methoddevelopment and programming timecan be saved.

Method programming for DL53/55/58 titrators becomes even easierwith the new memory card application packages. Fully developedtitration methods are already preprogrammed on the industry-specificmemory cards and can easily be loaded into the titrator.

Many users already know the ad-vantages of working with thememory card: methods and resultsare quickly stored, and data ofmethods and configuration are eas-ily transferred from one titrator toanother. This offers lots of optionsfor saving data and makes workingwith several titrators practicable,even without using a PC.

But why confine method transfer tojust one user?METTLER TOLEDO can offer alarge number of fully developed andtested methods. This expertise hasalready been made available to usersfor years in the form of applicationbrochures. The new memory cardapplication packages contain notonly copies of the methods, statisticsof the results and instructions on pa-per, but also the memory card itself,on which all the methods presentedin the associated brochure are storedelectronically. These methods can beloaded into the titrator without anyfurther ado, thus precluding any er-rors that might creep in if enteringthem manually. And then you just goahead and titrate !The application packages are cre-ated specifically for individual in-dustries, so that as many applica-tions as possible can be used fromthe one card. At the moment the fol-lowing memory card applicationpackages are available :• Determinations in the beverage

industry• Determinations in the paper in-

dustry• Titer determinations• TAN/TBN and other determina-

tions for oils

DL55 Titrator with Memory Cards

Applications


Titration in the Petroleum Industry

Crude oil is the source of 40 % of today’s energy production, whichmakes it one of the most traded goods in the world. Quality control isindispensable, and is regulated by various standards such as ASTM, IPor BSI. For their newest titrator line, the DL50 family, METTLERTOLEDO has developed methods for determining several key criteriaeasily and accurately.

In the first half of 1996 worldwide67,689 thousand barrels of crude oilwere produced every day; in thefirst half of 1997 this value had al-ready risen to 70,105 thousand bar-rels per day. This corresponds to anaverage growth of 3.6 %. The coun-tries with the highest production arethe USA, Saudi Arabia and theformer Soviet Union, whereas fromthe countries with a high productionVenezuela, Nigeria, Algeria andChina had the highest growth (seetable).This oil is partly used in the coun-tries it originates from and partly itis exported. All over the world oilproducts are refined and processedto petrol, diesel, motor oil, fuel oil,kerosene and petrochemicals andthe waste is mainly used as asphalt.

Among the biggest consumer coun-tries of petroleum products rangethe USA, the former Soviet Union,Japan, Germany, Rep. of China,Italy and France.To facilitate quality control severalstandards have been published, andASTM (American Society for Test-ing and Materials) is probably themost well-known source of stan-dards in the petroleum industry.ASTM was founded in 1898 withthe intent to “meet on a commonground”, to have a method withwhich the quality of products can betested and defined. Now, exactly100 years later, this is still the main

purpose of these standards. Theyalso have a growing worth concern-ing environmental aspects: withSBN- and SAN-standards, for in-stance, the quality of motor oil canbe determined so that it is onlychanged when needed, thus avoid-ing unnecessary waste.There are several ASTM standardsfor the petroleum industry, of whichthe strong acid and the acid number(SAN and AN), the strong base andthe base number (SBN and BN)along with the bromine number

Crude oil production in 1000 barrels per day,first half of year [1]

Country 1997 1996 Growth

USA 8331 8411 – 1.0 %Saudi Arabia 8169 8015 + 1.9 %Former USSR (CIS) 7158 7125 + 0.5 %Iran 3693 3698 – 0.1 %Mexico 3373 3312 + 1.8 %Norway 3295 3208 + 2.7 %China 3228 3093 + 4.4 %Venezuela 3224 2901 +11.1 %Canada 2508 2350 + 6.7 %UK 2478 2499 – 0.8 %Nigeria 2399 2210 + 8.6 %Emirates (UAE) 2300 2244 + 2.5 %Kuwait 1989 2007 – 0.9 %Indonesia 1553 1515 + 2.5 %Libya 1460 1424 – 2.5 %Algeria 1291 1234 + 4.6 %

World 70105 67689 + 3.6 %

range among the most frequentlyused determinations.These relatively elaborate determi-nations are all performed by poten-tiometric titration. METTLERTOLEDO has developed methodson their newly launched automatictitrators that allow fast and reliabledetermination of these values. Be-side these methods that strictly fol-low ASTM D 664-89 (SAN andAN), D 4739-92 and D 2896-92(SBN and BN) and ASTM 1159-93(Bromine number) a few other use-ful methods have been developed: aquick method for the SAN/AN andthe SBN/BN, a method for deter-mining the bromine index, mercap-tans in oil products and chloride incrude oil. All these have been pub-lished in METTLER TOLEDO’slatest applications brochure [2].

Applications


What are acid and base numbersgood for ?The SBN is a measure for theamount of strong bases in petroleumproducts. The strong bases are de-fined as basic compounds, with adissociation constant at least 1000times that of the next weakergroups. Basic compounds aremainly organic and inorganic bases,including amino compounds butalso salts of weak acids, basic saltsof polyacidic compounds and someadditives such as inhibitors or deter-gents.Strong acids are defined in the sameway as strong bases. Acidic com-pounds to be found in petroleumproducts are organic and inorganicacids, esters, phenolic compounds,lactones, resins, salts of ammoniaand others.Both the SBN/BN and the SAN/ANare used to indicate relative changes

200

– 200

0

mV

Buffer A

Buffer B

mL

Blank AHCl

Blank BKOH

Solvent

SAN

AN

Sample

ANAN

AN

Sample

Titration curve acid number

that occur in an oil during use underoxidizing or other service condi-tions, regardless of the color or otherproperties. They are used as indica-tion when the quality of the oil islow and when it needs replacing.

Bromine numberThe bromine number is the calcu-lated amount of bromine in grams toreact with 100 g of sample underthe conditions of the standard testmethod ASTM D 1159-93. Themagnitude of the bromine number isan indication of the quantity of bro-mine reactive constituents, mainlydouble bonds.

Quick methods and other methodsThe quick methods can be used inroutine checks. They allow a roughestimate of the true value in aboutone quarter of the time of theASTM methods.

The mercaptan determination fol-lows ASTM D3227 and is also usedfor quality control, whereas thechloride content of crude oil is im-portant because chloride affects thepipelines.

ConclusionMost of the ASTM determinationscall for several pretitrations beforethe actual titration is started - this isan ideal application for METTLERTOLEDO’s automatic titrators, forwhich methods have already beendeveloped and published in their lat-est memory card application pack-age “Determinations in the Petro-leum Industry”. They allow an exactand easy determination of all theimportant properties in petroleumproducts and can be performedwithout any special knowledge ofthe field.

References

[1] Petroleum Economist, Volume64 Number 10, London 1997

[2] Applications Brochure 20,Determinations in the PetroleumIndustry, METTLER TOLEDO


New Method for the Determinationof Vitamin C

Vitamin C content is an important factor for the quality control of foodand beverage products. This article describes the amperometric titra-tion of vitamin C, a new method with considerable advantages overclassical procedures, such as speed, accuracy and sensitivity.METTLER TOLEDO has developed a new automatic titrator that notonly allows amperometric titrations, but also provides the necessaryalgorithm for the appropriate evaluation.

Voltametric or amperometrictitration?In any titration the amount of titrantup to complete reaction with theanalyte has to be determined. Accu-rate indication of the equivalencepoint (equal amount of titrant andanalyte in moles) is a necessity foraccurate determination.In voltametric titration a constantcurrent I is applied to a double pinplatinum electrode and the potentialU is measured. In the titration ofascorbic acid with DPI, the potentialmeasured remains constant until allthe ascorbic acid has been oxidisedand excessive DPI is reduced at theelectrode. This results in a huge po-tential jump, that can be evaluatedby classical methods such as stan-dard evaluation [2] or Tubbs evalua-tion [3].

An alternative method is the am-perometric titration. Here the poten-tial U is kept constant and the cur-rent I is measured. According to lit-erature [5] the potential must bekept near the half wave-potentialπ

1/2. The half wave-potential indi-

cates how easily a substance can beoxidised or reduced and depends onthe acidity of the solution as fol-lows:

π1/2

(25 °C) =0.309 + 0.059 lg[H+]2 + 10-5.92[H+]

where 10-5.92 is the first dissociationconstant of ascorbic acid.

In the course of the titration I re-mains constant as long as DPI reactswith ascorbic acid. After the equiva-lence point the current rises propor-tionally to the amount of excessiveDPI.The titration curves of ampero-metric titrations show a “segmentedcurve”, i.e. two straight lines meet-ing at an equivalence point.METTLER TOLEDO has devel-oped the an alogarithm for threvaluation of segmented titrationcurves [4].

Ascorbic acid (vitamin C) is vitalfor human beings. Its absence in nu-trition leads to scurvy - once com-mon among sailors - and it is be-lieved to prevent viral infectionsand even cancer [1]. Even thoughthe two latter points are not proven,the vitamin C concentration in foodand beverage products is often men-tioned in specifications and there-fore has to be controlled by quanti-tative analysis.

How can we determine thevitamin C content?Various methods are applied for thedetermination of vitamin C,amongst them redox titrations withiodine or dichlorophenolindophenol(DPI) as titrants. Titration providesa fast, easy and accurate techniquein general, and DPI is an idealoxidising agent because of its selec-tivity for ascorbic acid. Indicationof the equivalence point can bedone potentiometrically, photo-metrically, voltametrically or - aspresented here - amperometrically.Ascorbic acid is a compound thatreadily oxidises as follows:

Fig. 2: Example of a voltametrictitration curve [4]

[mL]

[mV]

Fig. 3: Example of an amperometrictitration [4]

[mL]

[µA]

Fig. 1: Oxidation of ascorbic acid

O

O O

O OH

OH

OO

HO OH

OH

OH

– 2e–

Applications


Sample Originating Sample Content of RSD nfrom size Vitamin C [%]

[g] [mg/100 g]

Kiwi fruit freshly chopped 2 – 5 103.79 0.979 4Orange juice bottle 5 – 7 37.16 0.501 3Apricot juice bottle 5 – 7 41.51 0.477 4Lemon juice freshly squeezed 4 – 6 53.00 0.339 6Ribena bottle 10 53.06 0.044 3

Table 1: Different examples of vitamin C determinations

Comparison of the amperometricmethod with the voltametricindicationAmperometric titration has two ma-jor advantages in comparison to thevoltametric titration:

- Amperometric titration is fasterbecause the equilibration timeafter adding an increment oftitrant is shorter.

- Smaller concentrations can bedetermined than is possible withvoltametric indication since theamperometric indication ismore sensitive.

The amperometric titration withsegmented evaluation was appliedin several measurement series to de-termine the ascorbic acid content indifferent fruit juices (see table 1).

With useful side effects such asrelatively small sample sizes andshort measuring times (2 – 3 minper titration) the precision is veryhigh, which is expressed in a lowrelative standard deviation.

Instrument requirementsMETTLER TOLEDO titrators al-low the sequential programming ofsample preparation, dilution, titra-tion, evaluation, calculation and re-porting with a so-called methodconcept, wherein different stepssuch as DISPENSE, STIR, TITRA-TION, CALCULATION can becombined freely. This allows thecomplete automation of an analysissequence and hence liberates theoperator from routine work.Users are supported with a built-inmethod library for the most com-mon applications. Industry-specificMemory Card packages, e.g. for thebeverage industry provide addi-tional methods developed for a spe-cific field of interest to further fa-cilitate method development andhence problem solving.

References

[1] Römpp, Chemie Lexikon,Thieme Verlag

[2] Fundamentals of Titration,METTLER TOLEDO

[3] S. Ebel, E. Glaser, R.Kantelberg, B. Reyer, Auswer-tung digitaler Titrationskurvennach dem Tubbs-Verfahren,Fresenius Z Anal Chem, 1982(312), S. 604 - 607

[4] Applications Brochure 19,Determinations in Beverages,METTLER TOLEDO

[5] Polarographische Analyse;Krjukowa, Sinjakowa,Arefjewa; VEB DeutscherVerlag für Grundstoffindustrie,Leipzig 1964

Other books on this subject:- Quantitative AnalyticalChemistry; J. S. Fritz, G. H.Schenk, Allyn and Bacon, Inc.,Boston 1979- The Principals andApplications of Polarography,G. W. C. Milner, Longmans,London 1962

ConclusionFor the determination of the vitaminC content, titration with DPI andamperometric indication is the idealsolution: high selectivity of thechemical reaction, together withtimesaving but sensitive indicationand easy handling of the titratorsdue to the method concept allow afast and reliable analysis.

Fig. 4: Example of a typical titrationmethod

Title Method ID . . . . . . . . . . . . . MT071 Title . . . . . . . . . . . . . . . Vitamin C Date/time . . . . . . . . . . . . . 18-Jul-1996Sample Sample ID . . . . . . . . . . . . . orange juice Entry type . . . . . . . . . . . . . Weight Lower limit [g] . . . . . . . . . 5.0 Upper limit [g] . . . . . . . . . 7.0 Molar mass M . . . . . . . . . . . . 176.13 Equivalent number z . . . . . . . . 2 Titration stand . . . . . . . . . . Stand 1 Temperature sensor . . . . . . . . . ManualStir Speed [%] . . . . . . . . . . . . . 40 Time [s] . . . . . . . . . . . . . . 10EQP titration pol. Titrant/Sensor Titrant . . . . . . . . . . . . . 1/2 DPI Concentration [mol/L] . . . . . . 0.01 Sensor . . . . . . . . . . . . . DM142 Indication . . . . . . . . . . . . . Amperometric UPol [mV] . . . . . . . . . . . . 200.0 Predispensing . . . . . . . . . . . to volume Volume [mL] . . . . . . . . . . . 1 Titrant addition dV [mL] . . . . . . . . . . . . . 0.1 Measure mode . . . . . . . . . . . . Equilibrium contr. dE [mV, uA] . . . . . . . . . . . 0.5 dt [s] . . . . . . . . . . . . . 1.0 t(min) [s] . . . . . . . . . . . 3.0 t(max) [s] . . . . . . . . . . . 30.0 Recognition Threshold . . . . . . . . . . . . 3.0 Steepest jump only . . . . . . . No Range . . . . . . . . . . . . . . No Tendency . . . . . . . . . . . . Positive Termination at maximum volume [mL] . . . . . 10.0 at potential . . . . . . . . . . No at slope . . . . . . . . . . . . No after number EQPs . . . . . . . . Yes n = . . . . . . . . . . . . . 1 comb. termination conditions . . No Evaluation Procedure . . . . . . . . . . . . Segmented Potential 1 . . . . . . . . . . . No Potential 2 . . . . . . . . . . . No Stop for reevaluation . . . . . . Yes Condition . . . . . . . . . . neq=0Calculation Formula . . . . . . . . . . . . . . R=Q*C/m Constant . . . . . . . . . . . . . . C=M*100/z Decimal places . . . . . . . . . . . 4 Result unit . . . . . . . . . . . . mg/100g

Exhibitions, Conferences and Courses

Achemasia 98 May 11 – 16 1998 BeijingEastern-Analytical Symposium November 15 – 20 1998 Sommerset NJ

Titration Customer Courses and Seminars (CH)

Information and registration: Yvonne de BuhrTel. ++41 1 806 7219Fax ++41 1 806 7240E-Mail: [email protected]

DL course 45, Oil analysis (English) November 4 – 5 1998 Greifensee, Switzerland

Titration Customer Courses and Seminars (Germany)

For further information please contact Mettler-Toledo GmbH in GiessenTel. ++49 641 507 317

Titration Information Days and Training Courses (USA)Please contact your local instrument specialist or callTel. 1 800 METTLER (63 88 537)Fax 1 609 448 47 77

Regional Titration Seminars (UK)For further information please contact Mettler-Toledo LeicesterTel. 0116 234 50 25Fax 0116 234 50 25

If you have any questions concerning other meetings, the products or applications, please contact your localMETTLER TOLEDO dealer.

Editorial officeMettler-Toledo GmbH, AnalyticalSonnenbergstrasse 74CH-8603 Schwerzenbach, SwitzerlandTel. ++41 1 806 7711Fax ++41 1 806 7240E-Mail: [email protected]: http://www.mt.com

U. Bauer, J. Maag, V. Schindler, Dr. T. Fritz, Ch. Walter

Layout and ProductionMarket Support AnaChem Schwerzenbach, V. MahlerME-51709796

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Documents

titration customer courses

method id

mettler toledo

beverage products

petroleum industry

toledo gmbh

ascorbic acid

crude oil