A New HPLC-ELSD Method for Simultaneous Determination of N-Acetylglucosamine and N-Acetylgalactosamine in Dairy Foods
Table 6
Stability results for GlcNAc and GalNAc standard solutions after ten days at 4, 20, and 40°C ( independent replicates).
Compound
ST
FC
Stability (, mean) (°C)
Day 1
Day 2
Day 3
Day 7
Day 10
AS
RSD
AS
RSD
AS
RSD
AS
RSD
AS
RSD
GlcNAc
4
25
100.16
0.04
98.32
0.28
102.16
0.77
104.72
0.52
104.20
1.54
150
99.72
1.04
101.84
0.27
101.59
1.25
100.33
0.28
102.00
0.80
20
25
98.32
3.32
98.76
3.60
99.64
2.92
102.64
1.85
96.20
3.99
150
99.72
1.11
99.69
0.83
101.79
0.79
101.49
1.29
102.21
0.75
40
25
102.36
3.27
103.44
2.65
101.72
3.73
104.56
0.66
104.16
1.74
150
101.99
1.12
102.88
0.46
102.30
0.15
101.84
0.43
97.99
1.34
GalNAc
4
10
103.50
1.81
102.50
1.23
103.70
2.79
105.70
0.20
103.10
4.64
100
98.58
1.11
98.54
0.42
105.04
0.38
104.86
0.53
101.25
0.49
20
10
98.00
1.75
103.40
3.95
105.08
3.54
102.50
1.27
105.70
3.63
100
102.36
1.05
103.53
1.08
103.05
0.78
104.24
1.14
98.68
0.37
40
10
99.00
1.08
106.50
3.83
102.10
4.98
100.90
3.84
98.40
4.37
100
101.58
0.21
100.77
2.16
101.66
3.34
100.24
2.96
100.46
0.17
ST = storage temperature (°C). FC = fortified concentration (mg/L). AS = accuracy of stability test for GlcNAc and GalNAc (%). RSD = relative standard deviation (%).
