Major Ions

• Two samples on different concentration levels
• Two bottles (2 x 500 mL) per sample
• Natural samples: one ground water sample, one surface water sample (partly fortified)
  Details: UBA and Annual Programme 2023.
• Synthetic samples (IFA): Concentration comparable to ground and surface water, more details can be found here.
  
• The specified standard deviations for proficiency assessment (z-score-criteria in %) and lower limits apply to synthetic samples in the year 2023 and are calculated from interlaboratory comparisons 2012-2022. At regular intervals the standard deviations are recalculated and updated.



Parameter	standard deviation for proficiency assessment based on the target value	Lower limit
Alkalinity KS 4.3 (as H+)	1.9 %	0.2 mmol/L
Ammonium	11 %	0.01 mg/L
Boron	7.3 %	0.012 mg/L
Calcium	3.2 %	9 mg/L
Chloride	2.9 %	2 mg/L
Conductivity (25°C)	1.2 %	50 µS/cm
Cyanide 1)	16 %	0.01 mg/L
DOC	5.4 %	1 mg/L
Fluoride 4)	7.0 %	0.2 mg/L
Hydrogen carbonate	2.4 %	20 mg/L
KMnO4-Index (as O2) 2)	10 %	1 mg/L
Magnesium	3.5 %	1 mg/L
Total-N 3)	-	-
Nitrate	3.1 %	2 mg/L
Nitrite	5.4 %	0.01 mg/L
Orthophosphate	9.5 %	0.015 mg/L
pH value 3)	-	-
Potassium	4.3 %	0.5 mg/L
Silicon 4)	4.6 %	0.9 mg/L
Sodium	3.2 %	1 mg/L
Sulphate	3.1 %	3 mg/L
Total hardness	2.8 %	0.1 mmol/L
Total-P (as PO43-) 5)	9.4 %	0.015 mg/L


¹⁾ Easily liberatable cyanide EN ISO 14403-2:2012; ISO 6703-2:1984 (DIN 38405-D13) in round N168
²⁾ KMnO₄-Index (EN ISO 8467-H5) in rounds N167 and N169
³⁾ Total-N and pH value in N165 (natural samples)
⁴⁾ Total-Si (as Si) and fluoride in rounds N166 and N168
⁵⁾ Total-P (as PO₄^3-) (dissolved) after digestion (EN ISO 6878:2004)




Round	Dispatch	Organisation	Samples	Additional	Closing date
N165	07.02.2023	UBA	natural	Total-N, pH value	07.03.2023
N166	06.03.2023	IFA	synthetic	Si, F-	31.03.2023
N167	22.05.2023	IFA	synthetic	KMnO4-Index	23.06.2023
N168	04.09.2023	IFA	synthetic	Cyanide, Si, F-	29.09.2023
N169	06.11.2023	IFA	synthetic	KMnO4-Index	01.12.2023




• Contact IFA: Uta Kachelmeier, Ing.
  Phone: +43(0) 1 47654 97361
• Contact UBA: Martha Schmid, MSc.
  Phone: +43(0) 1 31304 4334