Determination of Nitrogen Fractions - Comments

Ammonium and Nitrate

Comments

Pretreatment and losses of analytes

Extraction conditions:

Reference to preatreatmentstudy and „interferences anderrors“

Changed: fresh samplesextracted in one step in 1M KCl, different ratios forsoil (1:5) and sludge andtreated biowaste (1:20-1:80)Measure an aliquot of thefiltrate or supernatant

Other Comments

Use of other extractants (AUST):

water, CaCl2 (0,02M), 2,5 M KCl

Dialysis step for purification from

humic acids (NEN)

Comparison to Recovery in prEN 14671 (FIN)

Analysis in different matrices 

Extractant 1:10 Ammonium mg/l

KCl 2 M 3,4 +/- 0,4

KCl 1 M 3,6 +/- 0,2

KCl 0,2 M 3,1 +/- 0,1

CaCl2 0,02 M 2,7 +/- 0,1

H2O, tridest 1,6 +/- 0,1

 

n = 2

Recovery in soilWEPAL soil, < 2 mm

KCl Ratio: (w/V)

Shaking time ( hours)

NH4-N

Recov. %

NO3-N

Recov. %

1 M 1 : 10 1 x 1 h 96 96

1 M 1 : 10 2 x 1 h 98 101

1 M 1 : 10 3 x 1 h 98 101

Recovery in treated biowasteKCl Ratio: sample /

extractantShaking time ( hours)

NH4-N % Recovery

2 M 1 : 5 1 x 1 h 71 +/- 6

2 M 1 : 10 1 x 1 h 85 +/- 7

2 M 1 : 5 2 x 1 h 87 +/- 7

2 M 1 : 10 2 x 1 h 92 +/- 7

1 M 1 : 5 1 x 1 h 66 +/- 6

1 M 1 : 10 1 x 1 h 88 +/- 7

1 M 1 : 10 2 x 1 h 81 +/- 7

1 M 1 : 10 1 x 2 h 76 +/- 6

1 M 1 : 10 16h standing at 20°C, then 1x1h

60 +/- 6