analisis de agua merck (1)

1.11151.0001

Compact Laboratory forwater testing

For the determination of:

ammonium, carbonate hardness (acid-binding capacity), total hardness (and residual hardness), nitrate, nitrite, pH, phosphate, oxygen and oxygen consumption, temperature

2

Introduction 3

Parameters and number of determinations 3

Package contents 3

Safety and shelf-life 3

Principles and definitions 4

Methods and measuring ranges / graduations 6

Sampling 7

General description of methods 7

General instructions for performing the analyses 8

Instructions for the determination of the individual parameters 9

Influence of foreign substances 14

Method control 16

Refill packs 17

Auxiliary tables* 18

1. Orientational values for grading the quality of water bodies 18

2. Conversion of hardness values 18

3. Factors for the approximate calculation of the concentration of free carbonic acid (CO2) from the acid-binding capacity (ABC) as afunction of pH 18

4. Oxygen saturation concentration of water (in mg/l) as a function of water temperature 19

5. Correction factors for the oxygen saturation index as a function of height above sea level resp. of atmospheric pressure 20

6. Optimum ranges, threshold values, and lethal limits of pH and water temperature for carp and rainbow trout 20

7. Percentage of free ammonia (NH3) in the total ammonium concentration as a function of water temperature and pH 21

8. Limits for free ammonia (NH3) for various fish species 21

References 21

Table of contents

* The data given in the auxiliary tables have beentaken from the scientific literature and may besubject to changes in accordance with the mostrecent state of research. In addition, limits maybe subject to upward or downward adjustmentdue to specific environmental conditions or thephysiological condition of organisms.

3

Introduction

The Aquamerck® Compact Labora-tory for Water Testing contains allthe reagents and auxiliaries neces-sary for the determination of theparameters of most relevance inconnection with the assessment ofthe quality of water bodies.

The Compact Laboratory is suitedfor numerous applications, forexample for monitoring the qualityof waters, for supporting analysesin connection with the biological

assessment of waters, and also inthe academic and teaching fields. The tests themselves are based oncolorimetric and titrimetric methods.In addition to the instructions foruse for the determination of theindividual parameters, this brochurecontains inter alia a section spe-cifically devoted to sampling, gen-eral instructions for performing theanalyses, and also detailed dataregarding the influence of foreignsubstances. This supplementary

information is also relevant for thedetermination of the individualparameters. In addition, on the en-closed colour cards to be used forthe colorimetric tests are providedbrief illustrated instructions.

At the end of this brochure, a collec-tion of tables and data is also pro-vided that enables a differentiatedassessment of water bodies andthe conversion and correction ofmeasurement values.

Ammonium: 50 determinations pH: 200 determinations

Carbonate hardness (acid-binding capacity): 150 determinations at 10 °d Phosphate: 100 determinations

Total hardness: 150 determinations at 10 °d Oxygen: 100 determinations at 8.5 mg/l O2

Nitrate: 100 determinations

Nitrite: 200 determinations

Reagents see “Instructions for the determinations of the individual parameters” (Titration pipettes are attached to 3 reagent bottles.)

1 graduated 5-ml plastic syringe

3 test vessels with red ring markings

1 flat plastic stopper

3 test tubes with screw caps

1 oxygen reaction bottle(glas bottle with slanted ground-glass stopperand plastic or glass mixing element)

1 sliding comparator(black plastic holder to accomodate 2 test tubes)

Please note the safety data sheets as well as the warningson the outer pack label and on the labels of the individualreagent bottles!

The reagents in the pack are stable up to thedates stated on the respective labels whenstored in the closed bottles at +15 to +25 °C.

Parameters and number of determinations

Package contents

Safety and shelf-life

1 colour card for ammonium

1 colour card for nitrate

1 colour card for nitrite

1 colour card for pH

1 colour card for phosphate

1 floating thermometer

1 sheet of round stickers(for identifying the water samplesand the screw caps of the reagentbottles)

4

Principles and definitions

pH

The degree to which an aqueoussolution is acidic or alkalinedepends on the respective concen-tration of the hydrogen ions (H+)and hydroxide ions (OH–) resultingfrom the dissociation of water. Thisis described by the following for-mula:

(concentration H+) x (concentrationOH–) = 10–14 [mol/l]2,

also referred to as the “ionic prod-uct of water”. From this formula it

follows that the concentration of theH+ ions or, respectively, of the OH–

ions can vary between 1 (= 100)mol/l and 10–14 mol/l upon the addi-tion of an acid or base. Additionally,this formula is also an expression ofthe fact that the concentration ofeither of these ions cannot be al-tered without affecting that of theother. For the characterization ofthe acidic or alkaline reaction of anaqueous solution, it is thus suffi-cient to state the concentration ofthe H+ ions. To avoid having to write

out the figure awkwardly usingdecimal potencies, for dilutedaqueous solutions it is standardpractice to use the negative decimallogarithm of the figure value of theH+ concentration. This is termed thepH value, or simply the pH.

pH = -lg (concentration H+)

Depending on the respective pH,solutions are referred to as beingacidic, neutral, or alkaline (basic):

Solution

acidic

strongly acidicweakly acidic

neutral

alkaline (basic)

weakly alkalinestrongly alkaline

pH

< 7

0–33–7

7

> 7

7–1111–14

H+ concentration in mol/l

> 10–7

10–7

(H+ concentration = OH– concentration)

< 10–7

Hydrochloric acid with a concentration of 1 mol/l has a pH of approximately 0, sodium hydroxide solution with a concentration of 1 mol/l a pH of approximately 14, purewater a pH of 7.

The hardness (total hardness) of awater is due to its content of saltsof the alkaline earth metals cal-cium, magnesium, strontium, andbarium (hardening constituents).Since strontium and barium gen-erally occur in waters only in traceamounts, the hardness is definedas the content in a water of calciumions (Ca2+) and magnesium ions(Mg2+) in mmol/l. It is, however, conventional practice to set thewater hardness in relation only to

calcium, i.e. to express also themagnesium portion (generallyapproximately 15–30 % of the totalhardness) as calcium concentration.

Officially the water hardness mustbe expressed in SI units, i.e. inmmol/l Ca2+. However, the Germandegree (°d) is often used as a prac-tical measurement unit; this is defined as follows:

1°d = 10 mg/l CaO

Since the molar mass of CaO is 56 mg/mmol, 10 mg CaO is equiv-alent to 10/56 = 0.178 mmol Ca2+,and the relation is thus

1 °d = 0.178 mmol/l Ca2+

or

1 mmol/l Ca2+ = 5.6 °d

Any hardness remaining after water-softening procedures is referred toas residual hardness.

Water hardness (For conversion of hardness values see “Auxiliary tables”, table 2)

5

Assessment of the water

soft

medium hard

hard

very hard

Water hardnessin °d in °e in mmol/l (Ca + Mg) in mg/l CaCO3

< 7 < 9 < 1.3 < 125

7–14 9–17.5 1.3–2.5 125–250

14–21 17.5–26 2.5–3.8 250–375

> 21 > 26 > 3.8 > 375

The carbonate hardness is that pro-portion of all those hardness ionsCa2+ and Mg2+ present in one litre ofwater for which there is an equiva-lent quantity of hydrogen carbonateions (HCO3

–) and carbonate ions(CO3

2–), which originate from dis-solved carbonic acid. When thewater boils for a relatively long time, except for a small amount, thehydrogen carbonates and carbon-ates of the hardening constituentsare precipitated as insoluble car-bonates. For this reason, the car-bonate hardness was formerly alsoreferred to as temporary hardness(in contrast to permanent hard-ness, which is caused by the sulfa-tes and chlorides of the hardeningconstituents).

The carbonate hardness is – like thetotal hardness – usually expressedin mmol/l Ca2+ or, respectively, in °d.

Since the hydrogen carbonate andcarbonate ions present in a waterare capable of binding acid (i.e. H+

ions), the carbonate hardness canalso be expressed as the acid-

binding capacity (ABC). This isunderstood as that quantity of 0.1 mhydrochloric acid that is required totitrate 100 ml of water to a pH of4.3. The acid-binding capacity of agiven water sample, which is set inrelation to the ions of carbonic acid,is exhausted at this pH, i.e. allhydrogen carbonate and carbonateions have taken up H+ ions, with theresult that only dissolved carbonicacid is still present. (This is why theGerman DIN 38409-H7 standardrecommends the term acid capacityto pH 4.3.) Since the acid-binding capacity isdetermined by means of titrationwith hydrochloric acid (addition ofmonovalent H+ ions), but on theother hand the carbonate hardnessis defined as the concentration ofbivalent hardness ions, the follow-ing formula applies:

ABC [mmol/l] / 2 = carbonatehardness[mmol/l Ca2+]

Using the formula stated in the sec-tion “Water hardness”

1 mmol/l Ca2+ = 5.6 °d

it follows that

ABC [mmol/l] / 2 = carbonate hardness [mmol/l Ca2+] = carbonate hardness [°d] / 5.6

or

ABC [mmol/l] x 2.8= carbonate hardness [°d]= carbonate hardness

[mmol/l Ca2+] x 5.6

The total hardness should alsoalways be determined along withthe carbonate hardness. This is be-cause some water samples containhydrogen carbonates and carbon-ates other than those of calciumand magnesium, meaning thatunder certain circumstances morehydrogen carbonate and carbonateions may be present than the quan-tity equivalent to the hardness ions.Thus, the value found for the car-bonate hardness may be higher thanthat found for the total hardness. Inthis case, for the carbonate hard-ness the value determined for thetotal hardness must be stated.

The reduction of the oxygen contentof a water caused by oxygen-con-suming chemical and biochemicalprocesses is generally referred to asoxygen consumption. When theoxygen depletion is due to micro-organisms and the measurement isperformed under defined conditions,this process is also referred to asbiochemical oxygen demand orBOD. The BOD is defined as that

amount of oxygen that is consumedby microorganisms in n days to oxi-datively degrade the organic sub-stances present in one litre of waterat a temperature of 20 °C. The BODprovides a point of reference for theassessment of a water regarding itsload with biologically oxidizable or-ganic substances and its biologicalactivity. The reason why the BOD is not

determined until after one or moredays is because biological proces-ses take considerably more timethan chemical processes. In mostcases organic substances havebeen biologically degraded to adegree of approximately 70 % afterfive days (n = 5). Therefore, theBOD is generally determined afterthis period of time (BOD5).

Oxygen consumption / biochemical oxygen demand (BOD)

Carbonate hardness (For conversion of hardness values see “Auxiliary tables”, table 2)

6

Methods and measuring ranges / graduations

AmmoniumNH4

+

Method

Ammonium reacts with a chlorinating agent to form monochloramine, which in turn reactswith thymol to form green 2,2’-isopropyl-5,5’methyl indophenol. This is then determinedcolorimetrically.

Measuring range / graduation

0 – 0.2 – 0.4 – 0.6 – 1 – 2 – 3 – 5 mg/l NH4

+

Carbonate hardnessacid-binding capacity The water sample is titrated with hydrochloric

acid (to pH 4.3), with an indicator changingfrom blue to red. All hydrogen carbonate andcarbonate ions present in the water sampleare measured in this titration or, respectively,the quantities of calcium and magnesium ionsequivalent to these ions.

Measuring range with 1 fullpipette: 0.2–20 °d(“ABC” 0.1–7.2 mmol/l)

Graduation of the titrationpipette:1 division = 0.2 °d (0.1 mmol/l)

Total hardnessCalcium and magnesium ions react with anindicator to form a red complex. Upon titrationwith Titriplex® III (ethylenedinitrilotetraaceticacid, disodium salt) the indicator is releasedfrom this complex, with a change in colour togreen.

Measuring range with 1 fullpipette: 0.2–20 °d(0.1–3.6 mmol/l)

Graduation of the titrationpipette:1 division = 0.2 °d (0.1 mmol/l)

NitrateNO3

– Nitrate becomes reduced to nitrite, which reactswith sulfanilic acid to form a diazonium salt.This in turn reacts with 2,5-dihydroxybenzoicacid to form an orange-yellow azo dye, whichis then determined colorimetrically.

0 – 10 – 25 – 50 – 75 – 100 –125 – 150 mg/l NO3

–

NitriteNO2

– Nitrite reacts with sulfanilic acid to form a diazonium salt, which in turn reacts with N-(1-naphthyl)ethylenediamine dihydrochlorideto form a red-violet azo dye. This is thendetermined colorimetrically.

0 – 0.025 – 0.05 – 0.075 – 0.1 –0.15 – 0.2 – 0.3 – 0.5 mg/l NO2

–

pHAn indicator added to the water sample as-sumes a colour dependent on the pH; thiscolour is then determined colorimetrically.

4.5 – 5 – 5.5 – 6 – 6.5 – 7 – 7.5– 8 – 8.5 – 9

PhosphatePO4

3– (orthophosphate) Orthophosphate ions react with molybdate ionsto form molybdatophosphoric acid. This is inturn reduced to phosphomolybdenum blue(PMB), which is then determined colorimetri-cally.

0 – 0.25 – 0.5 – 0.75 – 1.0 – 1.5 –2 – 3 mg/l PO4

3–

OxygenO2 Oxygen oxidizes bivalent manganese to higher-

valence manganese hydroxides. In the subse-quent reduction with iodide to Mn(II), a quantityof iodine equivalent to the dissolved oxygen isformed, with the solution changing to violet toblue in colour – depending on the oxygen con-tent – in the presence of starch as indicator.The iodine is then titrated with sodium thiosul-fate until decoloration of the solution.

Measuring range with 1 fullpipette: 0.1–10 mg/l O2

Graduation of the titrationpipette: 1 division = 0.1 mg/l O2

7

Sampling

In the case of surface waters, watersamples should be taken from dif-ferent places and from different depths, which are both to be recordedin a sampling protocol. Additionallythe weather conditions and otherspecial observations should also berecorded in the protocol.

In cases in which it is suspectedthat wastewater is being dis-charged, then a minimum of threesamples should be taken, namely a) from the suspected source of

discharge;b) from the polluted water down-

stream of the suspected point ofdischarge; and

c) from a nonpolluted section ofwater, wherever possible up-

stream from the suspected pointof discharge.

When investigating ponds andpools, samples should be taken formeasurement at least at the inflowand the outflow.

Clean, tightly closing glass orplastic bottles are suitable for thecollection of water samples.

It is advisable to take the individualsamples at a water depth of 20 to 50 cm. Prior to taking the actualsamples, the sample bottles must bethoroughly rinsed with the water tobe tested. The bottles are subse-quently filled and closed while sub-merged in the water, taking care

to avoid trapping air bubbles in thebottles.

Depending on the composition ofthe water sample, the concentra-tions of the substances containedcan change within a very shortspace of time as a result of physical,chemical, or biological processes.For this reason the samples shouldbe analyzed as soon as possibleafter they have been taken. Forshort-term storage the samplesshould be kept in a cool (2–5 °C)and dark place.

General description of methods

1. Colorimetric methodIn this method reagents are addedto the water sample that undergo acolour reaction with the respectivesubstance to be determined. Theintensity of the colour formed in this process is proportional to thecontent of the substance in question.This is why the colour of the mea-surement solution is then comparedwith the colour fields of a colourcard, each of which corresponds toa specific concentration. For thispurpose, the open test vessel con-taining the measurement sample ismoved along the row of colourfields, reading off the concentrationgiven for the field that best matchesthe sample when viewed fromabove (colour match).

In the Aquamerck® Compact Labo-ratory for water testing, with theexception of the phosphate determi-nation two test vessels are used foreach colour match. These vesselsare inserted into a so-called slidingcomparator; one vessel containsthe measurement sample, thesecond the blank (water samplewithout reagents). The comparatoris then moved along the colour carduntil the best possible colour matchis achieved when the open test ves-sels are viewed from above. Bymeans of the blank, any slight tur-bidities and intrinsic colorations ofthe water sample are automaticallycompensated for.

2. Titrimetric methodFirst an indicator is added to thesample. Then a reagent solution ofdefined concentration (titrationsolution) is added dropwise, toreact with the substance to bedetermined. Once the entire quan-tity of the substance in questionpresent in the measurement samplehas reacted (endpoint of the titra-tion), the indicator changes colour(colour change). The volume oftitration solution required to bringabout this change in colour isproportional to the content of thesubstance in question in the mea-surement sample. Therefore, in thetests using a titration pipette, thecontent to be determined can bedirectly read off from the graduationscale on the pipette.

8

General instructions for performing the analyses

� In connection with the ammonium,nitrate, nitrite, and phosphatetests, if the concentration of thesubstance in question is above therespective measuring range, thenthe water sample must be dilutedwith distilled or deionized water

� The dropping bottles must beheld vertically while adding thereagents. The drops must beadded slowly (approx. 1 drop persecond).

� The reagent bottles containingtitration solutions in this Compact Laboratory already havethe titration pipettes fitted. In therefill packs containing a titrationpipette, the pipette is positionedalongside the reagent bottles andmust be loosely attached to thebottle of titration solution in orderto draw up the syringe.

� While filling the titration pipettescare must be taken that no airenters the dropping tube. If thishappens, return the titration solu-tion to the reagent bottle andrepeat the process.

� The scales on the titration pi-pettes are specific to the respec-tive parameters. Care must there-fore be taken not to confuse thetitration pipettes.

� The microspoons integrated intothe screw caps of the reagentbottles must be used only forwithdrawing and adding therespective reagents. Do not allowthe microspoons to come intocontact with other reagents orsample materials.

� Each reagent bottle must beclosed with the respective screwcap immediately after withdrawalof the reagent. The enclosedstickers can be used to mark thescrew caps to avoid confusion.

before the analysis. The concen-tration of the diluted solutionshould ideally be approximatelyin the middle of the measuringrange. The measurement resultmust subsequently be multi-plied by the dilution factor.

� When performing titrimetric measurements, it is only the con-sumption of the titration solutionthat is dependent on the concen-tration of the substance to bedetermined, but not the con-sumption of the respective indi-cator solution. This is why thereis usually a remainder of one ofthe solutions when the other hasbeen fully used up.

� If the titration pipette is filledmore than once, higher valuesthan 1 pipette filling can be measured.

� Prior to their use, the test vesselsor test tubes must be rinsedseveral times with the water tobe tested.

� For the colorimetric tests, in addition to the detailed instruc-tions for use brief illustrated ver-sions are provided on the respec-tive colour cards.

9

Instructionsfor the determination of the individual parametersAmmoniumReagents:

1 bottle of1.08024.NH4-1

1 bottle of1.08024.NH4-2(with integratedblue microspoon)

1 bottle of1.08024.NH4-3

Procedure:

1. Remove two test tubes with screw caps and rinse severaltimes with the water to be tested.

2. By means of the plastic syringe, fill 5 ml of the watersample (20–30 °C) into each test tube.

3. Insert one of the two test tubes into the pointed half of thesliding comparator (blank). Do not add any reagents tothis tube.

4. To the other test tube intended for the measurement sample, add 12 drops of NH4-1, close the tube, andshake briefly.

5. Add 1 level microspoon of NH4-2, close the tube, andshake to dissolve.

6. After 5 min, add 4 drops of NH4-3, close the tube, andshake briefly.

7. Wait 7 min, then insert the test tube containing the mea-surement sample into the rounded half of the sliding com-parator. Place the comparator on the unfolded colour cardin such a way that the pointed end points to the numericalvalues.

8. Open the test tubes and move the comparator along thecolour scale until the best possible colour match is obtai-ned when the two tubes are viewed from above.

9. Read off the value indicated by the pointed end of thecomparator in mg/l NH4

+ or, respectively, estimate an inter-mediate value.

Notes:

� Analyze samples immedi-ately after sampling.

� Filter turbid water samplesprior to the determination.

� Since ammonium ions arein a pH-dependent equilibriumwith dissolved free ammonia(NH3), also the latter is mea-sured in the form of ammo-nium ions in this determina-tion. Thus this test alwaysmeasures the “total ammo-nium concentration”.

Carbonate hardness (acid-binding capacity)Reagents:

1 bottle of1.08048.CH-1

1 bottle of1.08048.CH-2(with fitted titration pipette “°d – SBV mmol/l”)

Procedure:

1. Remove one test vessel with red ring markings and rinseseveral times with the water to be tested.

2. By means of the plastic syringe, fill the test vessel with thewater sample to the 5-ml mark.

3. Add 3 drops of CH-1 and swirl carefully. The solution turnsblue in colour if any hardening constituents are present.

4. Remove the reagent bottle containing CH-2. Hold the bottleupright and slowly draw up the plunger of the fitted titrationpipette from the lowest position until the lower edge of theblack plunger seal coincides with the zero mark of thescale. (The dropping tube is now filled with titration solution.)

5. Detach the titration pipette from the reagent bottle andbriefly wipe the tip of the dropping tube.

6. Slowly add the titration solution, dropwise and with swirl-ing, to the water sample until the colour changes from bluevia grey-violet to red. Shortly before the colour change,wait a few seconds after each drop is added, swirlingthe test vessel each time.

7. At the lower edge of the black plunger seal, from the corre-sponding scale of the titration pipette read off the carbon-ate hardness in °d or, respectively, the acid-binding capacity(ABC) in mmol/l.

8. Return any titration solution still remaining in the titrationpipette to the reagent bottle and screw the pipette tightlyback on to the bottle.

Notes:

The total hardness shouldalso always be determinedalong with the carbonatehardness. If the value foundfor the carbonate hardness ishigher than the value foundfor the total hardness, thelatter must be taken also asthe result for the carbonatehardness (see “Principles anddefinitions”).

10

Total hardnessReagents:

1 bottle of1.08039. ·1.08033. ·1.11122.H-1

1 bottle of 1.08039. ·1.08033. ·1.08203.H-2(with fitted titration pipette“°d – mmol/l”)

Procedure:



3. Add 3 drops of H-1 and swirl carefully. The solution turnsred in colour if any hardening constituents are present.

4. Remove the reagent bottle containing H-2. Hold the bottleupright and slowly draw up the plunger of the fitted titrationpipette from the lowest position until the lower edge of theblack plunger seal coincides with the zero mark of thescale. (The dropping tube is now filled with titration solution.)


6. Slowly add the titration solution, dropwise and with swirl-ing, to the water sample until the colour changes from redvia grey-violet to green. Shortly before the colour change,wait a few seconds after each drop is added, swirlingthe test vessel each time.

7. At the lower edge of the black plunger seal, from the corre-sponding scale of the titration pipette read off the totalhardness in °d or, respectively, in mmol/l.


Notes:

The pH of the water sampleshould be within the range 6–8. Adjust, if necessary,with sodium hydroxide solution or hydrochloric acid.

Residual hardnessReagents:

1 bottle of1.08039. ·1.08033. ·1.11122.H-1

Procedure:



3. Add 3 drops of H-1 and swirl carefully. Depending on theresidual hardness present, the colour of the reaction solu-tion changes as follows:

green: 0 °d (0 °e), i.e. no residual hardnessgrey-violet: 0.1 °d (0.1 °e)red-violet: 0.5 °d (0.6 °e)red: over 0.5 °d (0.6 °e)

Notes:

The pH of the water sampleshould be within the range 6–8. Adjust, if necessary, withsodium hydroxide solution orhydrochloric acid.

NitrateReagents:

1 bottle of 1.11170.NO3-1(with integratedgreen microspoon)

Procedure:


2. By means of the plastic syringe, fill 5 ml of the watersample into each test tube.

3. Insert one of the two test tubes into the pointed half of thesliding comparator (blank). Do not add any reagent tothis tube.

4. To the other test tube intended for the measurement sample, add 2 level microspoon of NO3-1, close the tube,and shake vigorously for 1 min to dissolve.

Notes:


� Any black residues occurr-ing in the measurementsample are due to the reac-tion mechanism and have noeffect on the measurementresult.

(continued next page)

11

Nitrate (continued)Reagents: Procedure:


6. Open the test tubes and move the comparator along thecolour scale until the best possible colour match is obtainedwhen the two tubes are viewed from above.

7. Read off the value indicated by the pointed end of the com-parator in mg/l NO3

– or, respectively, estimate an inter-mediate value.

Notes:

� In determining nitrate, nitrite concentrations exceed-ing 0.5 mg/l are also detected(see “Influence of foreign substances”). The resultanterror can be corrected approx-imately by calculation asfollows:Actual nitrate content= result for nitrate

– 1.35 x result for nitrite

NitriteReagents:

2 bottles of 1.08025.NO2-1

1 bottle of1.08025.NO2-2(with integratedgrey microspoon)

Procedure:



3. Insert one of the two test tubes into the pointed half of thesliding comparator (blank). Do not add any reagents tothis tube.

4. To the other test tube intended for the measurement sample, add 5 drops of NO2-1, close the tube, and shakebriefly.

5. Add 1 level microspoon of NO2-2, close the tube, andshake to dissolve.



8. Read off the value indicated by the pointed end of thecomparator in mg/l NO2

– or, respectively, estimate an inter-mediate value.

Notes:

� Analyze samples imme-diately after sampling.

� Filter turbid water samplesprior to the determination.(For filtration use glass-fibrepaper or a membrane filterwashed with hot water.)

pHReagents:

1 bottle of1.08027.pH-1

Procedure:



3. Insert one of the two test tubes into the pointed half of thesliding comparator (blank). Do not add any reagent tothis tube.

4. To the other test tube intended for the measurement sam-ple, add 2 drops of pH-1, close the tube, and shake briefly.

5. Insert the test tube containing the measurement sampleinto the rounded half of the sliding comparator. Place thecomparator on the unfolded colour card in such a way thatthe pointed end points to the numerical values.


7. Read off the pH value indicated by the pointed end of thecomparator or, respectively, estimate an intermediate value.

Notes:

� To distinctly recognize thecolour tone of the indicator,the samples should be colour-less and clear, or only faintlycoloured and slightly turbid.

� After the determination,rinse the test tubes usingdistilled water only.

12

PhosphateReagents:

1 bottle of 1.14661.PO4-1

1 bottle of1.14661.PO4-2(with integratedblue microspoon)

Procedure:



3. Add 5 drops of PO4-1 and swirl carefully. 4. Add 1 level microspoon of PO4-2, close the test vessel

with the flat plastic stopper, and dissolve the reagent byshaking.

5. Wait 2 min, then open the test vessel and place on thewhite area between the two rows of colour fields of thecolour card.

6. Move the test vessel along the white area until the colourof the measurement solution – when viewed from above –best matches one of the colour fields.

7. Read off the measurement value in mg/l PO43– or, respec-

tively, estimate an intermediate value.

Notes:

� The pH of the water sampleshould be within the range 5–8. Adjust, if necessary,with sodium hydroxidesolution or sulfuric acid.


� After the determination,rinse the test vessel withdistilled water. Do not useany phosphate-containingdetergents.

OxygenReagents:

1 bottle of1.11107. · 1.11152.O2-1

1 bottle of1.11107. · 1.11152.O2-2

2 bottles of1.11107. · 1.11152.O2-3

1 bottle of1.11107. · 1.11152.O2-4

1 bottle of1.11107. · 1.11152.O2-5(with fitted titrationpipette “mg/l”)

Procedure:

1. Rinse the oxygen reaction bottle several times with thewater to be tested. Subsequently fill bubble-free tooverflowing.

2. Add 5 drops of O2-1 and then 5 drops of O2-2, close thebottle with the glass stopper, shake well, and leave tostand closed for 1 min (a precipitate may be formed).

3. Add 10 drops of O2-3, reclose with the glass stopper, and shake well.

4. Remove one test vessel with red ring markings, rinseseveral times with the solution obtained in step 3, thenuse the plastic syringe to fill the test vessel with thissolution to the 5-ml mark.

5. Add 1 drop of O2-4 to the test vessel and mix.Depending on the oxygen content, the solution now turnsviolet to blue in colour.

6. Remove the reagent bottle containing O2-5. Hold the bottleupright and slowly draw up the plunger of the fitted titra-tion pipette from the lowest position until the lower edgeof the black plunger seal coincides with the zero mark ofthe scale. (The dropping tube is now filled with titrationsolution.)


8. Slowly add the titration solution, dropwise and with swirl-ing, to the solution in the test vessel until the colour changes from blue to colourless. Shortly before thecolour change, wait a few seconds after each drop isadded, swirling the test vessel each time.

9. At the lower edge of the black plunger seal, read off theoxygen content in mg/l.


Notes:

� Analyze samples immedi-ately after sampling. If thisis not possible, immediatelyperform steps 1 and 2 to fixthe oxygen contained in thesample. The closed reactionbottle, which must be free ofair bubbles, can then be stored for a maximum of 24 hours, instead of 1 min asstated in step 2 (in a coolplace protected from light).

� Some liquid overflows whileadding reagents 1 and 2 andwhile inserting the ground-glass stopper. The glass bottleshould therefore be placed, ifnecessary, in a bowl or on aninsensitive surface (e.g. filterpaper).

� In the case of very highconcentrations of oxygen, anadditional 1 to 3 drops ofreagent 3 must be added tocompletely dissolve the precipitate.

� Should a blue coloration ofthe solution recur after thetitration has been completed,this must not be taken intoaccount.

13

Oxygen consumptionReagents:

see under “Oxygen”

Procedure:

1. Determine the oxygen content immediately after samplingand – if necessary – aeration of the sample:Rinse the oxygen reaction bottle several times with samplewater or, respectively, with aerated sample water.Subsequently fill bubble-free to overflowing, and performsteps 2 to 10 stated under “Oxygen” (result A).

2. Rinse the oxygen reaction bottle several times with samplewater or, respectively, with aerated sample water. Then fillbubble-free to overflowing as in step 1, but this time donot add any reagents. Close the bottle and store for ndays in the dark at 20 °C. (In most cases 5 days are appro-priate; see “Principles and definitions”.) Subsequently per-form anew steps 2 to 10 stated under “Oxygen” (result B).

Oxygen consumption in mg/l O2 = result A– result B

Notes:

� In the case of a low oxygencontent and a high oxygenconsumption (high organicload), the samples must beaerated at 20 °C prior to thedetermination (e.g. by stirringwith a glass rod). Enrichmentwith oxygen is essential if –for the unaerated sample –result B is lower than 2 mg/lO2.

� Samples containing higherorganisms (zooplankton) yieldfalse-high oxygen consump-tion values.

14

Tolerable concentrations of foreign substances in mg/l – matrix influence

for ammonium:

Al3+ 100Ca2+ 100Cl– 1000Cr3+ 100Cr2O7

2– 100Cu2+ 100F– 1000Fe2+ 10Fe3+ 100Mg2+ 100Mn2+ 10Na+ 1000

NO2– 100

NO3– 1000

PO43– 1000

Polyphosphates 1000S2– 1SiO3

2– 1000SO3

2– 100SO4

2– 1000Zn2+ 1000

Free chlorine 100EDTA 1000Cationic surfactants 100Anionic surfactants 10Oxidizing agents 100

Seewater andbrackish water:suitable as samplematerial

Water containinghumic substances:suitable as samplematerial

for carbonate hardness:

Al3+ 10

Cl– 1000Cr3+ 100Cr2O7

2– 10Cu2+ 1000F– 100Fe2+ 10Fe3+ 10

Mn2+ 1000Na+ 1000NH4

+ 1000NO2

– 100NO3

– 1000PO4

3– 1000Polyphosphates 1000S2– 100SiO3

2– 100SO3

2– 100SO4

2– 1000Zn2+ 1000


Seewater andbrackish water:not suitable as samplematerial


for total hardness:

Al3+ 100

Cl– 1000Cr3+ 10Cr2O7

2– 100Cu2+ 1F– 100Fe2+ 10Fe3+ 10

Mn2+ 10Na+ 1000NH4

+ 1000NO2

– 1000NO3

– 1000PO4


2– 1000SO3

2– 1000SO4

2– 1000Zn2+ 10




for nitrate:

Al3+ 10Ca2+ 100Cl– 1000Cr3+ 1Cr2O7

2– 1Cu2+ 10F– 100Fe2+ 10Fe3+ 1Mg2+ 100Mn2+ 100Na+ 100NH4

+ 100NO2

– 0.5

PO43– 100


2– 100SO3

2– 100SO4

2– 1000Zn2+ 100




Influence of foreign substances

The concentrations of foreign sub-stances given in the following tableslie below the limits at which theindividual determinations are inter-fered with.

The influence of surfactants wastested using the following substances:

Cationic surfactants:N-cetylpyridinium chloride Anionic surfactants:Na-dodecyl sulfate

Hydrogen peroxide was used asoxidizing agent.

Seawater and brackish water were

prepared in the following densitiesusing natural sea salt:

Seawater 1.024 g/mlBrackish water 1.015 g/ml

Water containing humic substanceswas prepared by diluting peatextract.

15

Tolerable concentrations of foreign substances in mg/l – matrix influence

for nitrite:

Al3+ 1000Ca2+ 1000Cl– 1000Cr3+ 100Cr2O7


+ 1000

NO3– 1000

PO43– 1000


2– 100SO3

2– 10SO4

2– 1000Zn2+ 1000

Free chlorine 0,1EDTA 1000Cationic surfactants 100Anionic surfactants 10Oxidizing agents 1



for phosphate:

Al3+ 1000Ca2+ 1000Cl– 1000Cr3+ 1Cr2O7


+ 1000NO2

– 1000NO3

– 1000

S2– 1SiO3

2– 1000SO3

2– 1000SO4

2– 1000Zn2+ 1000




for oxygen:

Al3+ 100Ca2+ 1000Cl– 1000Cr3+ 1Cr2O7


+ 1000NO2

– 10NO3

– 1000PO4


2– 1000SO3

2– 100SO4

2– 1000Zn2+ 100

Free chlorine 1EDTA 10Cationic surfactants 10Anionic surfactants 10Oxidizing agents 0.1



for pH:



Water containinghumic substances:yields false-low results

16

Method control

The correct function of the test rea-gents, the auxiliaries, and the modeof working can be checked easilyfor some of the tests described here.For this purpose, a correspondingstandard solution is diluted to aconcentration that lies roughly inthe middle of the measuring rangeof the respective test. The resultantsolution is then analyzed in thesame way as a normal sample. Ifthe measurement result equals thedesired value (concentration of

the standard solution x dilutionfactor), the reagents and auxiliariesare in good order and the analysishas been performed correctly.

In the case of the pH test, an un-diluted buffer solution with a pH of7.00 is analyzed at 20 °C.

By analyzing the water sample afterthe addition of a defined quantity ofstandard solution (standard addi-tion, spiking), it is possible to check

the tests for ammonium, nitrate,nitrite, and phosphate as to whetherthe measurement results areinfluenced by other substances pre-sent in the water sample (matrixeffect). If there is no matrix effect,the recovery rate must be 100 %.

The standard solutions given beloware available for the described con-trol measurements.

Item

Ammonium standard solution Ammonium chloridein water

Nitrate standard solution Sodium nitrate in water

Nitrite standard solution Sodium nitritein water

Buffer solution

Phosphate standard solution Potassium dihydrogen phosphate in water

Ordering No.

1.19812.0500

1.19811.0500

1.19899.0500

1.09439.1000

1.19898.0500

Content / pH

1000 mg/l NH4+

1000 mg/l NO3–

1000 mg/l NO2–

pH 7.00 (at 20 °C)

1000 mg/l PO43–

17

Refill packsItem

Aquamerck® Ammonium Test with colour card

Aquamerck® Carbonate Hardness Test – with titration pipetteAcid binding capacity (ABC)

Aquamerck® Total Hardness Test with titration pipette

Aquamerck® Total Hardness Test, without titrationRefill pack for 1.08039.0001 pipette

Aquamerck® Total Hardness Test,H-1Refill pack for 1.08039.0001

Aquamerck® Total Hardness Test,H-2Refill pack for 1.08039.0001

Aquamerck® Nitrate Test with colour card

Aquamerck® Nitrite Test with colour card

Aquamerck® pH Test with colour card

Aquamerck® Phosphate Test with colour cardin freshwater and seawater

Aquamerck® Oxygen Test with oxygenreaction bottle andwith titration pipette

Aquamerck® Oxygen Test, without oxygenRefill pack for 1.11107.0001 reaction bottle and

without titration pipette

Aquamerck® Oxygen Reaction Bottle

Flat-bottomed tubes for Microquant® tests(= test tubes with screw caps)

Ordering No.

1.08024.0001

1.08048.0001

1.08039.0001

1.08033.0001

1.11122.0001

1.08203.0001

1.11170.0001

1.08025.0001

1.08027.0001

1.14661.0001

1.11107.0001

1.11152.0001

1.14663.0001

1.14902.0001

Number of determinations /Package contents

50 determinations

300 determinations at 12.5 °e(“ABC” 3.6 mmol/l)

300 determinations at 12.5 °e

300 determinations at 12.5 °e

600 Tests in combinationwith 1.08203.0001

600 Tests in combinationwith 1.11122.0001

200 determinations

200 determinations

400 determinations

100 determinations

100 determinationsat 8.5 mg/l O2

100 determinationsat 8.5 mg/l O2

1 bottle

12 test tubes

18

Auxiliary tables

Orientational values for grading the quality of water bodies

Quality class I II III IV

Organic load unpolluted to very moderately strongly extremelyslightly polluted polluted polluted polluted

BOD5 value in mg/l 1–2 2–8 8–20 >20

Oxygen minimum in mg/l >8 >6 >2 <2

Oxygen saturation in % 86–100 50– 85 20–40 <10100–110 110–150 150–200 >230

pH acidic 6.5–7.0 6.0–6.5 5.0–5.5 <5.0alkaline 7.0–7.5 8.0–8.5 9.0–9.5 10.0

Ammonium in mg/l <0.1 0.1–1 >2 >5

Nitrate in mg/l <1.0 1–5 >5

Nitrite in mg/l <0.1 0.2–0.5 4.0–6.0 8.0

Orthophosphate in mg/l <0.03 <0.5 >0.5

Total hardness in mmol/l ca. 3.6 ca. 5.3 ca. 7.1

Acid-binding capacityin mmol/l 0.5–1.0 0.25–0.5 0.03–0.1 0.05

Iron in mg/l 0–0.1 0.1–0.2 ca. 0.5 1.0

Chloride in mg/l <80 80–500 1500–3500 >3500

Conversion of hardness values

Conversion mmol/l mg/l (ppm) German degree English degree French degree mg/l (ppm)Ca2+ + Mg2+ Ca2+ °d °e °f CaCO3

1 mmol/l1 40.08 5.60 7.02 10.00 100.0Ca2+ + Mg2+

1 mg/l (ppm)0.025 1 0.140 0.175 0.25 2.5Ca2+

1 German degree °d 0.18 7.14 1 1.25 1.78 17.8

1 English degree °e 0.14 5.71 0.799 1 1.43 14.3

1 French degree °f 0.10 4.00 0.560 0.700 1 10.0

1 mg/l (ppm)0.01 0.40 0.056 0.070 0.10 1CaCO3

1

2

Factors for the approximate calculation of the concentration of free carbonic acid (CO2) from the acid-binding capacity (ABC) as a function of pH (from Hütter, 1990)

pH Factor pH Factor pH Factor pH Factor

6.1 94 6.6 30.0 7.1 9.4 7.6 3.0

6.2 75 6.7 24.0 7.2 7.5 7.7 2.4

6.3 59 6.8 19.0 7.3 5.9 7.8 1.9

6.4 47 6.9 15.0 7.4 4.7 7.9 1.5

6.5 37 7.0 12.0 7.5 3.7 8.0 1.2

Example:Measured values: ABC 1.5 mmol/l; pH 7.1Factor from table = 9.4Concentration of free carbonic acid = ABC x factor = 1.5 mmol/l x 9.4 = 14.1 mg/l CO2

3

19

Oxygen saturation concentration of water (in mg/l) as a function of water temperature (acc. to Oehme and Schuler, 1983)

The stated values relate to oxygen concentrations of pure water in equilibrium with atmospheric air (air-saturated water and water-vapour-saturated atmosphere) and apply for standard pressure, i.e. 1013 hPa (1013 mbar resp. 760 Torr).

There are slight variations in the values given in diverse publications for the oxygen saturation concentration ofwater. The data in the table correspond to the latest scientific status.

Temperature°C .0 .1 .2 .3 .4 .5 .6 .7 .8 .9

0 14.64 14.60 14.55 14.51 14.47 14.43 14.39 14.35 14.31 14.27

1 14.23 14.19 14.15 14.10 14.06 14.03 13.99 13.95 13.91 13.87

2 13.83 13.79 13.75 13.71 13.68 13.64 13.60 13.56 13.52 13.49

3 13.45 13.41 13.38 13.34 13.30 13.27 13.23 13.20 13.16 13.12

4 13.09 13.05 13.02 12.98 12.95 12.92 12.88 12.85 12.81 12.78

5 12.75 12.71 12.68 12.65 12.61 12.58 12.55 12.52 12.48 12.45

6 12.42 12.39 12.36 12.32 12.29 12.26 12.23 12.20 12.17 12.14

7 12.11 12.08 12.05 12.02 11.99 11.96 11.93 11.90 11.87 11.84

8 11.81 11.78 11.75 11.72 11.69 11.67 11.64 11.61 11.58 11.55

9 11.53 11.50 11.47 11.44 11.42 11.39 11.36 11.33 11.31 11.28

10 11.25 11.23 11.20 11.18 11.15 11.12 11.10 11.07 11.05 11.02

11 10.99 10.97 10.94 10.92 10.89 10.87 10.84 10.82 10.79 10.77

12 10.75 10.72 10.70 10.67 10.65 10.63 10.60 10.58 10.55 10.53

13 10.51 10.48 10.46 10.44 10.41 10.39 10.37 10.35 10.32 10.30

14 10.28 10.26 10.23 10.21 10.19 10.17 10.15 10.12 10.10 10.08

15 10.06 10.04 10.02 9.99 9.97 9.95 9.93 9.91 9.89 9.87

16 9.85 9.83 9.81 9.78 9.76 9.74 9.72 9.70 9.68 9.66

17 9.64 9.62 9.60 9.58 9.56 9.54 9.53 9.51 9.49 9.47

18 9.45 9.43 9.41 9.39 9.37 9.35 9.33 9.31 9.30 9.28

19 9.26 9.24 9.22 9.20 9.19 9.17 9.15 9.13 9.11 9.09

20 9.08 9.06 9.04 9.02 9.01 8.99 8.97 8.95 8.94 8.92

21 8.90 8.88 8.87 8.85 8.83 8.82 8.80 8.78 8.76 8.75

22 8.73 8.71 8.70 8.68 8.66 8.65 8.63 8.62 8.60 8.58

23 8.57 8.55 8.53 8.52 8.50 8.49 8.47 8.46 8.44 8.42

24 8.41 8.39 8.38 8.36 8.35 8.33 8.32 8.30 8.28 8.27

25 8.25 8.24 8.22 8.21 8.19 8.18 8.16 8.15 8.14 8.12

26 8.11 8.09 8.08 8.06 8.05 8.03 8.02 8.00 7.99 7.98

27 7.96 7.95 7.93 7.92 7.90 7.89 7.88 7.86 7.85 7.83

28 7.82 7.81 7.79 7.78 7.77 7.75 7.74 7.73 7.71 7.70

29 7.69 7.67 7.66 7.65 7.63 7.62 7.61 7.59 7.58 7.57

30 7.55 7.54 7.53 7.51 7.50 7.49 7.48 7.46 7.45 7.44

31 7.42 7.41 7.40 7.39 7.37 7.36 7.35 7.34 7.32 7.31

32 7.30 7.29 7.28 7.26 7.25 7.24 7.23 7.21 7.20 7.19

33 7.18 7.17 7.15 7.14 7.13 7.12 7.11 7.09 7.08 7.07

34 7.06 7.05 7.04 7.02 7.01 7.00 6.99 6.98 6.97 6.96

35 6.94 6.93 6.92 6.91 6.90 6.89 6.88 6.87 6.85 6.84

36 6.83 6.82 6.81 6.80 6.79 6.78 6.77 6.75 6.74 6.73

37 6.72 6.71 6.70 6.69 6.68 6.67 6.66 6.65 6.64 6.63

38 6.61 6.60 6.59 6.58 6.57 6.56 6.55 6.54 6.53 6.52

39 6.51 6.50 6.49 6.48 6.47 6.46 6.45 6.44 6.43 6.42

40 6.41 6.40 6.39 6.38 6.37 6.36 6.35 6.34 6.33 6.32

Example:

Measured values: water temperature 10.5 °C; oxygen concentration 9 mg/lOxygen saturation concentration from table = 11.12 mg/l

4

20

5

6

The oxygen concentration measured at a specific water temperature and the oxygen saturation concentration given in the table for the same temperature can be used to calculate the oxygen saturation index (relative oxygensaturation in %):

Oxygen saturation index =Oxygen concentration (measured value)

x 100 %Oxygen saturation concentration (from table)

Example:Measured values: water temperature 10.5 °C; oxygen concentration 9 mg/l Oxygen saturation concentration from table = 11.12 mg/lOxygen saturation index = 9 x 100 / 11.12 = 80.9 %

Assuming a constant oxygen concentration, according to the equation given above the oxygen saturation indexincreases when the oxygen saturation concentration of water decreases. The latter is the case at increasing heightabove sea level, i.e. when the atmospheric pressure drops.

Table 5 gives the correction factors for the oxygen saturation index as applicable for various heights above sea level.

Dissolved salts reduce the oxygen saturation concentration.

Correction factors for the oxygen saturation indexas a function of height above sea level resp. of atmospheric pressure (from Schwoerbel, 1979)Height Pressure Factor Height Pressure Factorm hPa (mbar) m hPa (mbar)

0 1013 1.00 1300 862 1.17

100 1000 1.01 1400 852 1.19

200 988 1.03 1500 841 1.20

300 976 1.04 1600 830 1.22

400 964 1.05 1700 820 1.24

500 952 1.06 1800 810 1.25

600 940 1.08 1900 801 1.26

700 928 1.09 2000 792 1.28

800 916 1.11 2100 782 1.30

900 905 1.12 2200 773 1.31

1000 894 1.12 2300 764 1.33

1100 884 1.15 2400 754 1.34

1200 873 1.16 2500 746 1.36

Example:Height above sea level 400 m resp. atmospheric pressure 964 hPa; calculated oxygen saturation index 80.9 %Corrected oxygen saturation index = calculated oxygen saturation index x factor from table = 80.9 % x 1.05 = 84.9 %

Conversion of different pressure units:1 hPa (hectopascal) = 1 mbar (millibar) = 0.75 Torr1 Torr = 1 mm Hg = 1.333 hPa

Optimum ranges, threshold values, and lethal limits of pH and water temperature for carp and rainbow trout (from Steffens, 1981)

Fish species pHOptimum range Threshold value Lethal limit

Carp 6.5–8.0 5.5 ; 10.0 4.8 ; 10.8

Rainbow trout 6.5–7.5 5.5 ; 9.0 4.8 ; 9.2

Fish species Water temperature in °COptimum range Threshold value* Lethal limit

Carp 22–28 0 ; 36 38

Rainbow trout 12–16 20 26

* with habituation

21

8

7

Limits for free ammonia (NH3) for various fish species (from Bohl, 1982)

Fish species Limit in mg/l NH3

Rainbow trout, fry (rt0–1) 0.006

Rainbow trout, 1–2 years old (rt1–2) 0.01

Carp 0.02

Eel 0.01

Percentage of free ammonia (NH3) in the total ammonium concentration as a function of water temperature and pH (from Steffens, 1981)

Temperature pH°C 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0

0 0.00827 0.0261 0.0826 0.261 0.820 2.55 7.64 20.7 45.3

1 0.00899 0.0284 0.0898 0.284 0.891 2.77 8.25 22.1 47.3

2 0.00977 0.0309 0.0977 0.308 0.968 3.00 8.90 23.6 49.4

3 0.0106 0.0336 0.106 0.335 1.05 3.25 9.60 25.1 51.5

4 0.0115 0.0364 0.115 0.363 1.14 3.52 10.3 26.7 53.5

5 0.0125 0.0395 0.125 0.394 1.23 3.80 11.1 28.3 55.6

6 0.0136 0.0429 0.135 0.427 1.34 4.11 11.9 30.0 57.6

7 0.0147 0.0464 0.147 0.462 1.45 4.44 12.8 31.7 59.5

8 0.0159 0.0503 0.159 0.501 1.57 4.79 13.7 33.5 61.4

9 0.0172 0.0544 0.172 0.542 1.69 5.16 14.7 35.3 63.3

10 0.0186 0.0589 0.186 0.586 1.83 5.56 15.7 37.1 65.1

11 0.0201 0.0637 0.201 0.633 1.97 5.99 16.8 38.9 66.8

12 0.0218 0.0688 0.217 0.684 2.13 6.44 17.9 40.8 68.5

13 0.0235 0.0743 0.235 0.738 2.30 6.92 19.0 42.6 70.2

14 0.0254 0.0802 0.253 0.796 2.48 7.43 20.2 44.5 71.7

15 0.0274 0.0865 0.273 0.859 2.67 7.97 21.5 46.4 73.3

16 0.0295 0.0933 0.294 0.925 2.87 8.54 22.8 48.3 74.7

17 0.0318 0.101 0.317 0.996 3.08 9.14 24.1 50.2 76.1

18 0.0343 0.108 0.342 1.07 3.31 9.78 25.5 52.0 77.4

19 0.0369 0.117 0.368 1.15 3.56 10.5 27.0 53.9 78.7

20 0.0397 0.125 0.396 1.24 3.82 11.2 28.4 55.7 79.9

21 0.0427 0.135 0.425 1.33 4.10 11.9 29.9 57.5 81.0

22 0.0459 0.145 0.457 1.43 4.39 12.7 31.5 59.2 82.1

23 0.0493 0.156 0.491 1.54 4.70 13.5 33.0 60.9 83.2

24 0.0530 0.167 0.527 1.65 5.03 14.4 34.6 62.6 84.1

25 0.0569 0.180 0.566 1.77 5.38 15.3 36.3 64.3 85.1

26 0.0610 0.193 0.607 1.89 5.75 16.2 37.9 65.9 85.9

27 0.0654 0.207 0.651 2.03 6.15 17.2 39.6 67.4 86.8

28 0.0701 0.221 0.697 2.17 6.56 18.2 41.2 68.9 87.5

29 0.0752 0.237 0.747 2.32 7.00 19.2 42.9 70.4 88.3

30 0.0805 0.254 0.799 2.48 7.46 20.3 44.6 71.8 89.0

Example:Measured values: water temperature 12 °C; pH 7.5; ammonium concentration 2 mg/lPercentage of free ammonia from table = 0.684 %Concentration of free ammonia = measured ammonium concentration x percentage from table / 100 = 2 mg/l x 0.684 / 100 = 0.014 mg/l NH3

ReferencesBohl, M.; 1982: Zucht und Produktion von Süßwasserfischen. DLG-Verlag, Frankfurt (Main)Hütter, L. A.; 1990: Wasser und Wasseruntersuchung. Otto Salle Verlag, Frankfurt (Main) and Verlag Sauerländer, AarauOehme, F., & Schuler, P.; 1983: Gelöst-Sauerstoff-Messung. A. Hüthig Verlag, HeidelbergSchwoerbel, J.; 1979: Einführung in die Limnologie. UTB; Gustav Fischer Verlag, Stuttgart, New YorkSteffens, W.; 1981: Moderne Fischwirtschaft – Grundlagen und Praxis. Verlag J. Neumann-Neudamm, Melsungen

Merck KGaA64271 Darmstadt, GermanyTel. (0 6151) 720Fax (0 6151) 72 20 00 9.

7111

1.51

20/0

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0040

8686

analisis de agua merck (1)

Environment

determinations ph

function of water temperature

conversion of hardness

residual hardness

determinationstotal

general instructions

d oxygen

number of determinations