Instruction Manual

Methods

COD Reagents

Selecttheappropriatevialforthedesiredrange*:

LR-Range:  0–150mg/l,partnumber251990Y,25count   

MR-Range:  0–1500mg/l,partnumber251991Y,25count  

HR-Range:  0–15000mg/l,partnumber251992Y,25count

*Reagents are also availble in 150 count packages.

Preparing the Sample

Openareactionvialwithawhitecapandaddthespeciedvolume.

(Ensurethatappropriatepersonnelsafetyequipmentisused.)

LR-/MR: 2 ml water sample

HR: 0.2 ml water sample

Prepareablank(Note1)byusingdeionizedwater(TOC-free)insteadofthesample

(LR/MR: 2 ml, HR: 0.2 ml).

Replacethecaptightly.Invertthevialgentlyseveraltimestomixthecontents(Thevialwillbecome

hotduringmixing!)anddigestthevialsfor120minutesinthereactoratatemperatureof150°C.

Removethevialsfromthereactorandallowthemtocooldownto60°Corless.Mixthecontentsby

invertingeachvialseveraltimeswhilestillwarm.Thenallowthevialstocooltoambienttemperature

beforemeasuring.

Guidelines for photometric measurements

1. Runsamplesandblankswiththesamebatchofvials.

Theblankisstablewhenstoredinthedarkandcanbeusedforfurthermeasurementswithvials

fromthesamebatch.

2. Don‘tplacehotvialsintheadapter.Allowthevialstocooltoroomtemperaturefor

a minimum 45 minutes. It is recommended to leave the vials to cool over night.

3. Suspended solids in the vial lead to incorrect measurements. For this reason it is important to place

thevialscarefullyintheadapter.Theprecipitantatthebottomofthesampleshouldnotbe

suspended.

4. Cleantheoutsideofthevialswithatoweltoremovengerprintsorothermarks

5. Avoidspillageofwaterorreagentsolutionintothesamplechamberbecausethiscanleadtoincor-

rect test results.

6. Contaminationofthetransparentcellchambercanresultinincorrectreadings.Checkatregularin-

tervalsand–ifnecessary–cleanthetransparentcellchamberusingamoistclothorcottonswab.

7. Largetemperaturedifferencesbetweentheinstrumentandtheenvironmentcanleadtoerrors–

e.g.duetotheformationofcondensationinthecellchamberoronthevial.

8. Toavoiderrorscausedbystraylightdonotusetheinstrumentinbrightsunlight.