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Table 1 Ratio of compounds identified per treatment tested in relation to fresh samples

From: Freeze-drying: an alternative method for the analysis of volatile organic compounds in the headspace of urine samples using solid phase micro-extraction coupled to gas chromatography - mass spectrometry

Treatment

Mean

Median

S.E.

Mann–Whitney

Freeze-dry

5.18

6.03

0.45

Fresh

1.00

1.03

0.02

<0.001

HCl

5.96

6.15

0.35

0.231

NaCl

0.99

1.02

0.02

<0.001

NaOH

2.97

2.82

0.09

<0.001

Frozen

0.99

1.06

0.05

<0.001

  1. The number of compounds identified by each treatment were normalized by the average number of compounds identified in urine samples analysed fresh (SE = standard error). Mann–Whitney U test compared the number of metabolites reported by each treatment in relation to Freeze-dry