Line Filter NH2P-LF
For the analyses with Asahipak NH2P-50 column, it is recommended to use a line filter, NH2P-LF. Here, the way how to connect NH2P-LF is explained.
As shown in the figure below, NH2P-LF should be installed upstream of the injector. NH2P-LF is used to trap the extraneous substances in the eluent and not in the sample. Therefore, sample pretreatment and/or use of guard column is still necessary to prevent the deterioration of column by the impurities in the sample.
Asahipak NH2P-50 can be more easily with using a line filter, NH2P-LF. Figure (b) is a chromatogram after using NH2P-50 without NH2P-LF for 50 hours, and it is clear that the column performance has changed compared with the initial chromatogram (figure (a)). The reason of the change is not the deterioration of the column but the contamination of the column by extraneous substances such as heavy metals from devece and anions in the eluent. Figure (c) is a chromatogram after using NH2P-50 with NH2P-LF for 135 hours. We can see that there is almost no change between (a) and (c). Regarding the way how to connect NH2P-LF, refer to Connection of NH2P-LF.
Column : Shodex Asahipak NH2P-50 4E (4.6mmID*250mm) Eluent : CH3CN/H2O=75/25 Flow rate : 1.0mL/min Detector : Shodex RI Column temp. : 25deg-C
When Asahipak NH2P-50 is used, it is recommended to use line filter, NH2P-LF with it. Figure (A) and (B) show the effect of NH2P-LF. Figure (A) shows that the column resolution is same for about 135 hours, however, figure (B) shows that the column resolution decreases just after it is used.
Regarding figures (a), (b) and (c), refer to Effect of Line Filter NH2P-LF (1).
Sample : 0.2% each, 5micro-L
1. meso-Erythritol, 2. Xylitol, 3. Fructose, 4. Mannose, 5. Glucose
6. myo-Inositol, 7. Sucrose, 8. Lactose, 9. Maltose, 10. Raffinose
Column : Shodex Asahipak NH2P-50 4E (4.6mmID*250mm) Eluent : CH3CN/H2O=75/25 Flow rate : 1.0mL/min Detector : Shodex RI Column temp. : 25deg-C
When Asahipak NH2P-50 is used, it is recommended to use NH2P-LF with it. Here, the way how to clean NH2P-LF and NH2P-50 is explained.
(1) When NH2P-LF is not used with NH2P-50, the column performance will deteriorate from just after it is used.
(2) When NH2P-LF is used with NH2P-50, the column performance is unchanged for considerably long time.
(3) Although NH2P-LF is used with NH2P-50, the column performance will deteriorate after it is used for a certain period. To prevent the deterioration, it is necessary to clean NH2P-LF at regular interavals.
(4) Before the deterioration of the column start, it is necessary to clean just NH2P-LF to maintain the column performance.
(5) After the deterioration of the column start, it is necessary to clean both NH2P-LF and NH2P-50 to regenerate the column performance.
(Cleaning method)
Dismount NH2P-LF and NH2P-50 from the HPLC system, and connect NH2P-LF or NH2P-50 to the pump in the reverse way. The flow rate should be 1.0mL/min for NH2P-LF and 0.5mL/min for NH2P-50. NH2P-LF and NH2P-50 should be cleaned separately according to the way described in the right table.
Do not connect anything after NH2P-LF or NH2P-50. If a detector is connected, detector cell may be damaged by the alkaline solvent. And if NH2P-50 is connected after NH2P-LF, the extraneous substances in the NH2P-LF may move to NH2P-50 and cause the deterioration of NH2P-50.
| Cleaniong solvent |
NH2P-LF | NH2P-50 4D | NH2P-50 4E |
|---|---|---|---|
| 1. H2O |
5min
|
6min
|
10min
|
| 2. 0.1M HClO4 |
60min
|
75min
|
120min
|
| 3. H2O |
5min
|
6min
|
10min
|
| 4. 0.1M NaOH |
5min
|
6min
|
10min
|
| 5. H2O |
60min
|
75min
|
120min
|
| 6. Eluent |
10min
|
12min
|
20min
|