It should never be assumed that measurement results arebasically correct; there is always a possibility that they errorsmay have occurred at some stage of the analysis procedure.

In the field of chemical analysis, possible sources of error arethe materials used, the handling routines associated with theanalytical system, and the water samples to be analyzed(matrix influences).

The errors influence the accuracy and precision of the resultsof the measurements.

Accuracy: deviation of the results from the actual con-centration;

Precision: scatter of the results among each other.

Accurate and precise results of measurements are howeverthe prerequisite for:

• complying with and monitoring limiting values• the control of production• conditioning and purification processes.

Moreover, these measurements are used as a basis formaking decisions that often involve large financial expen-diture. As the responsibility for the measurement results liesin principle with the user, he must be certain about thequality of his results.

In the operation analysis sector Dr. Lange has developed anAQA system which is specially tailored to the requirements ofthe user – the 4-pillar concept. This allows the user to achieveaccurate, precise and comparable analytical results.

The basis of this 4-pillar concept is addista .

AnalyticalQuality Assurance (AQA)(The 4-pillar concept)

Assurance with addista

Summary:

Consistent application of the 4 pillars of the analytical quality assurance system provides the user with an effective means ofchecking and monitoring his analysis results.The fundamental advantages for the user are:

• reproducible analysis results• reliable measurement data as an aid to assessment and decision-making• analytical security through recognition of interferences and handling errors

The 4-pillar concept

Control of handling Analysis External check Comparabilityand materials of a water sample for of the measuring system to reference method

interferences and handling

addista Standard solutions Spikings solutions Ring test solutions Ref./cuvette test compara-components bility investigation in the

Dr. Lange standard laboratory

Recommended every 10th sample, every 20th sample, Twice per year Twice per yearminimum frequency at least once per month at least once every 3 month per cuvette test per paramter

(depends on person)

Documentation Standard control card Recovery control card Ring test evaluation Investigation reportwith diploma

Quality AssuranceLCA addista

Data table addista

Edition: 4/02

GB

Test expressed as Standardnominal value max. deviation

mg/l mg/l

Spiking resultnominal value max. deviation

mg/l mg/l

LCA 701 LCK 306LCK 321LCK 329LCK 337LCK 353LCK 360

Pb (II)Fetot.

Cu (II)NiSO4

Zn

0.5 ± 0.13 ± 0.152 ± 0.12 ± 0.1

500 ± 502 ± 0.15

0.25 ± 0.151.5 ± 0.21 ± 0.151 ± 0.15

250 ± 601 ±0.2

LCA 702 LCK 301LCK 308LCK 313

LCK 353

AlCdCr (VI)Crtot.

SO4

0.3 ± 0.020.2 ± 0.030.5 ± 0.050.5 ± 0.05500 ± 50

0.15 ± 0.030.1 ± 0.040.25 ± 0.060.25 ± 0.06250 ± 60

LCA 703 LCK 049

LCK 114LCK 303

LCK 311LCK 339

LCK 350

LCK 353LCK 384

PO4-PPO4

CODNH4-NNH4

ClNO3-NNO3

PO4-PPO4

SO4

TOC

10 ± 130.5 ± 3500 ± 3025 ± 1.5

32.2 ± 250 ± 36 ± 0.4

26.6 ± 1.810 ± 1

30.5 ± 3500 ± 50160 ± 25

5 ± 1.515.3 ± 4.6250 ± 4012.5 ± 216.1 ± 2.625 ± 43 ± 0.5

13.3 ± 2.25 ± 1.5

15.3 ± 4.5250 ± 6080 ± 30

LCA 704 LCK 153LCK 305

LCK 311LCK 314LCK 340

LCK 349

LCK 383

SO4

NH4-NNH4

ClCODNO3-NNO3

PO4-PPO4

TOC

100 ± 155 ± 0.5

6.4 ± 0.650 ± 350 ± 625 ± 2

110.7 ± 91 ± 0.1

3.05 ± 0.316 ± 2.5

50 ± 202.5 ± 0.63.2 ± 0.7725 ± 425 ± 8

12.5 ± 2.555.4 ± 110.5 ± 0.151.53 ± 0.46

8 ± 3

LCA 700 LCK 238LCK 304

LCK 311LCK 328LCK 348

LCK 414

Ntot.

NH4-NNH4

ClKPO4-PPO4

COD

20 ± 21 ± 0.1

1,28 ± 0.1350 ± 330 ± 52,0 ± 0.26,1 ± 0.6130 ± 3

10 ± 2,50.5 ± 0.150.64 ± 0.1925 ± 415 ± 61 ± 0.25

3.05 ± 0.7615 ± 4

LCA 705 LCK 014LCK 302LCK 311

CODNH4-NNH4

Cl

5000 ± 30080 ± 10103 ± 1350 ± 3

2500 ± 40040 ± 15

51.5 ± 19.325 ± 4

LCA 706 LCK 521LCK 529LCK 537LCW032

Fetot.

Cu (II)NiMn

0,2 ± 0.030,5 ± 0.050,5 ± 0.050,5 ± 0.1

0.1 ± 0.040.25 ± 0.060.25 ± 0.060.25 ± 0.15

LCA 707 LCK 341

LCK 348totalLCK 614

NO2-NNO2

PO4-PPO4

COD

0.3 ± 0.030.99 ± 0.1

2 ± 0.26.1 ± 0.61200 ± 8

0.15 ± 0.040.5 ± 0.131 ± 0.25

3.05 ± 0.76100 ± 10

LCA 709 LCK 138LCK 342

LCK 349totalLCK 614

Ntot.

NO2-NNO2

PO4-PPO4

COD

6 ± 0.93 ± 0.3

9,85 ± 11 ± 0.1

3.05 ± 0.3200 ± 8

3 ± 1.51.5 ± 0.44.9 ± 1.30.5 ± 0.151.53 ± 0.46100 ± 10

Ntot.

PO4-PPO4

COD

60 ± 610 ± 1

30.5 ± 31000 ± 40

30 ± 85 ± 1.5

15.3 ± 4.5500 ± 50

LCA 708 LCK 338LCK 350totalLCK 514

Quality AssuranceLCA addista

Data table addista

Edition: 4/02

Test expressed as Standardnominal value max. deviation

mg/l mg/l

Spiking resultnominal value max. deviation

mg/l mg/l

GB

CODLCK 414 (5 – 60 mg/l) 3.0 LCA 700 COD 30 mg/l +/- 3 mg/l 15 mg/l +/- 4 mg/l

CODLCK 514 (100 – 2000 mg/l) – LCA 708 COD 1000 mg/l +/- 40 mg/l 500 mg/l +/- 50 mg/l

CODLCK 014 (1.000 – 10.000 mg/l) 2.5 LCA 705 COD 5000 mg/l +/- 300 mg/l 2500 mg/l +/- 400 mg/l

CODLCK 114 (150 – 1.000 mg/l) 2.0 LCA 703 COD 500 mg/l +/- 30 mg/l 250 mg/l +/- 40 mg/l

CODLCK 314 (15 – 150 mg/l) 3.0 LCA 704 COD 50 mg/l +/- 6 mg/l 25 mg/l +/- 8 mg/l

Cuvette-Test max. VC addista Evaluation Confidence Interval Confidence Interval(Measuring range) [%] as . . . nom. value of max. nom. value of max.

stand. concen. deviation spiking solut. deviation

Ammonium-NitrogenLCK 303 (2 – 47 mg/l) NH4-N 3.5 LCA 703 NH4-N 25 mg/l +/- 1.5 mg/l 12,5 mg/l +/- 2 mg/l

(2.5 – 60.0 mg/l) NH4 NH4 32.2 mg/l +/- 2 mg/l 16,1 mg/l +/- 2.6 mg/l

Ammonium-NitrogenLCK 302 (47 – 130 mg/l) NH4-N – LCA 705 NH4-N 80 mg/l +/- 10 mg/l 40 mg/l +/- 15 mg/l

(60 – 167 mg/l) NH4 NH4 103 mg/l +/- 13 mg/l 51,5 mg/l +/- 19,3 mg/l

AluminiumLCK 301 (0.02 – 0.50 mg/l) 3.0 LCA 702 Al 0.3 mg/l +/- 0.02 mg/l 0.15 mg/l +/- 0.03 mg/l

Ammonium-NitrogenLCK 304 (0.015 – 2.0 mg/l) NH4-N 3.0 LCA 700 NH4-N 1 mg/l +/- 0.1 mg/l 0.5 mg/l +/- 0.15 mg/l

(0.02 – 2.50 mg/l) NH4 NH4 1.28 mg/l +/- 0.13 mg/l 0.64 mg/l +/- 0.19 mg/l

Ammonium-NitrogenLCK 305 (1 – 12 mg/l) NH4-N 3.0 LCA 704 NH4-N 5 mg/l +/- 0.5 mg/l 2.5 mg/l +/- 0.6 mg/l

(1.3 – 15.0 mg/l) NH4 NH4 6.4 mg/l +/- 0.6 mg/l 3.2 mg/l +/- 0.77 mg/l

CadmiumLCK 308 (0.02 – 0.3 mg/l) 5.0 LCA 702 Cd 0.2 mg/l +/- 0.03 mg/l 0.1 mg/l +/- 0.04 mg/l

Chlorine/Ozone/Chlorine dioxideLCK 310 (0.05 – 2.0 mg/l) Chlorine/Ozone 3.0 – – – – – –

(0.09 – 3.8 mg/l) ClO2

ChlorideLCK 311 (1 – 70 mg/l) 3.0 LCA 700 Cl 50 mg/l +/- 3 mg/l 25 mg/l +/- 4 mg/l

LCA 703LCA 704LCA 705

Chromium (total +VI)LCK 313 (0.03 – 1.0 mg/l) 3.0 LCA 702 Cr (VI) 0.5 mg/l +/- 0.05 mg/l 0.25 mg/l +/- 0.06 mg/l

Cr tot. 0.5 mg/l +/- 0.05 mg/l 0.25 mg/l +/- 0.06 mg/l

Quality of Dr. Langeprecision Cuvette-TestsDefinitions of the used statistical data

VC: Variation coefficient [%] = precision(Procedure variation coefficient)

German standard refering to DIN 38402-A51. Scale for thedeviation in % all over the total measuring range of a specifiedtest and all over Dr. Lange’s different types of instruments.Max. VC: max. variation coefficient [%]

(max. procedure variation coefficient)

Dr. Lange companies’ internal standard concerning the abovementioned DIN but evaluated under stronger conditions.Confidence interval: scale for accuracyThe standard for addista standard should be determinedwithin this range.Max. deviation range [mg/l]:Acceptable tolerance around the addista standard-concen-tration or standard-concentration in mg/l.

PhenolsLCK 346 (5 – 50 mg/l) I 3.0 – – – – – –

(20 – 200 mg/l) II – – – – – – –

NitriteLCK 342 (0,6 – 6 mg/l) NO2-N – LCA 709 NO2-N 3 mg/l +/- 0.3 mg/l 1.5 mg/l +/- 0.4 mg/l

(2 – 20 mg/l) NO2 NO2 9.85 mg/l +/- 1 mg/l 4.9 mg/l +/- 1.3 mg/l

CODLCK 614 (50 – 300 mg/l) – LCA 707 COD 200 mg/l +/- 8 mg/l 100 mg/l +/- 10 mg/l

LCA 709

ManganeseLCW 032 (0.02 – 5.0 mg/l) – LCA 706 Mn 0.5 mg/l +/- 0.1 mg/l 0.25 mg/l +/- 0.15 mg/l

Copper 50 mm Cuvette-TestLCK 529 (0.01 – 1.0 mg/l) – LCA 706 Cu (II) 0.5 mg/l +/- 0.05 mg/l 0.25 mg/l +/- 0.06 mg/l

CopperLCK 329 (0.1 – 8.0 mg/l) 2.0 LCA 701 Cu (II) 2 mg/l +/- 0.1 mg/l 1 mg/l +/- 0.15 mg/l

FormaldehydeLCK 325 (0.5 – 10.0 mg/l) 2.0 – – – – – –

CyanideLCK 315 (0.01 – 0.6 mg/l) 5.0 – – – – – –

Cuvette-Test max. VC addista Evaluation Confidence Interval Confidence Interval(Measuring range) [%] as . . . nom. value of max. nom. value of max.

stand. concen. deviation spiking solut. deviation

LeadLCK 306 (0.1 – 2.0 mg/l) 5.0 LCA 701 Pb (II) 0.5 mg/l +/- 0.1 mg/l 0.25 mg/l +/- 0.15 mg/l

IronLCK 321 (0.2 – 6.0 mg/l) 2.0 LCA 701 Fe tot. 3 mg/l +/- 0.15 mg/l 1.5 mg/l +/- 0.2 mg/l

® Total NitrogenLCK 138 (1 – 16 mg/l) – LCA 709 Nges 6 mg/l +/- 0.9 mg/l 3 mg/l +/- 1.5 mg/lLATON

Total NitrogenLCK 238 (1 – 40 mg/l) – LCA 700 Ntot. 20 mg/l +/- 2 mg/l 10 mg/l +/- 2.5 mg/lLATON

Total NitrogenLCK 338 (20 – 100 mg/l) – LCA 708 Ntot. 60 mg/l +/- 6 mg/l 30 mg/l +/- 8 mg/lLATON

NitrateLCK 339 (0.23 – 13.5 mg/l) NO3-N 2.5 LCA 703 NO3-N 6 mg/l +/- 0.4 mg/l 3 mg/l +/- 0.5 mg/l

(1 – 60 mg/l) NO3 NO3 26.6 mg/l +/- 1.8 mg/l 13.3 mg/l +/- 2.2 mg/l

NitrateLCK 340 (5 – 35 mg/l) NO3-N 4.0 LCA 704 NO3-N 25 mg/l +/- 2 mg/l 12.5 mg/l +/- 2.5 mg/l

(22 – 155 mg/l) NO3 NO3 110.7 mg/l +/- 9 mg/l 55.4 mg/l +/- 11 mg/l

NitriteLCK 341 (0.015 – 0.6 mg/l) NO2-N 3.0 LCA 707 NO2-N 0.3 mg/l +/- 0.03 mg/l 0.15 mg/l +/- 0.04 mg/l

(0.05 – 2.0 mg/l) NO2 NO2 0.99 mg/l +/- 0.1 mg/l 0.5 mg/l +/- 0.13 mg/l

PhenolsLCK 345 (0.05 – 5.0 mg/l) 3.0 – – – – – –

Iron 50 mm Cuvette-TestLCK 521 (0.01 – 1.0 mg/l) – LCA 706 Fe tot. 0.2 mg/l +/- 0.03 mg/l 0.1 mg/l +/- 0.04 mg/l

FluorideLCK 323 (0.1 – 1.5 mg/l) 3.0 – – – – – –

MagnesiumLCK 326 (0.5 – 10.0 mg/l) I 3.5 – – – – – –

(10 – 50 mg/l) II – – – – – – –

NickelLCK 337 (0.1 – 6.0 mg/l) 2.0 LCA 701 Ni 2 mg/l +/- 0.1 mg/l 1 mg/l +/- 0.15 mg/l

Nickel 50 mm Cuvette-TestLCK 537 (0.05 – 1.0 mg/l) – LCA 706 Ni 0.5 mg/l +/- 0.05 mg/l 0.25 mg/l +/- 0.06 mg/l

Phosphate-phosphorus ortho + totalLCK 348 (0.5 – 5.0 mg/l) PO4-P 2.0 LCA 700 PO4-P 2 mg/l +/- 0.2 mg/l 1 mg/l +/- 0.25 mg/l

(1.5 – 15.0 mg/l) PO4 LCA 707 PO4 6.1 mg/l +/- 0.61 mg/l 3.05 mg/l +/- 0.76 mg/l

OrthophosphateLCK 049 (1.6 – 30 mg/l) PO4-P 2.0 LCA 703 PO4-P 10 mg/l +/- 1 mg/l 5 mg/l +/- 1.5 mg/l

(5 – 90 mg/l) PO4 PO4 30.5 mg/l +/- 3 mg/l 15.3 mg/l +/- 4.6 mg/l

SilverLCK 355 (5 – 400 mg/l) I 3.0 – – – – – –

(400 – 2500 mg/l) II – – – – – – –

Water HardnessLCK 327 (1 – 20 °dH) 5.0 – – – – – –

Phosphate-phosphorus ortho + totalLCK 349 (0.05 – 1.5 mg/l) PO4-P 1.5 LCA 704 PO4-P 1 mg/l +/- 0.1 mg/l 0.5 mg/l +/- 0.15 mg/l

(0.15 – 4.5 mg/l) PO4 LCA 709 PO4 3.05 mg/l +/- 0.3 mg/l 1.53 mg/l +/- 0.46 mg/l

Phosphate-phosphorus ortho + totalLCK 350 (2 – 20 mg/l) PO4-P 2.0 LCA 703 PO4-P 10 mg/l +/- 1 mg/l 5 mg/l +/- 1.5 mg/l

(6 – 60 mg/l) PO4 LCA 708 PO4 30.5 mg/l +/- 3 mg/l 15.3 mg/l +/- 4.5 mg/l

PotassiumLCK 328 (8 – 50 mg/l) 5.0 LCA 700 K 30 mg/l +/- 5 mg/l 15 mg/l +/- 6 mg/l

SulphateLCK 153 (40 – 150 mg/l) 5.0 LCA 704 SO4 100 mg/l +/- 15 mg/l 50 mg/l +/- 20 mg/l

SulphateLCK 353 (150 – 900 mg/l) 9.0 LCA 701 SO4 500 mg/l +/- 50 mg/l 250 mg/l +/- 60 mg/l

LCA 702LCA 703

ZincLCK 360 (0.2 – 6.0 mg/l) 3.0 LCA 701 Zn 2 mg/l +/- 0.15 mg/l 1 mg/l +/- 0.2 mg/l

Cuvette-Test max. VC addista Evaluation Confidence Interval Confidence Interval(Measuring range) [%] as . . . nom. value of max. nom. value of max.

stand. concen. deviation spiking solut. deviation

TOCLCK 383 (5 – 50 mg/l) – LCA 704 TOC 16 mg/l +/- 2.5 mg/l 8 mg/l +/- 3 mg/l

TOCLCK 384 (50 – 500 mg/l) – LCA 703 TOC 160 mg/l +/- 25 mg/l 80 mg/l +/- 30 mg/l