This depends on how long you want to shut down your instrument for and what software version you are using.  If you are running the Biochrom 20 Control Software Version 3.02 or higher them you have a few more options please go to Section 1 below.  In any other situation you must decide how long you intend to leave the system shut down.  If you intend to leave it in a shutdown state longer than 1 month then please go to Section 2.  If the system is going to be unused for over a week then it is a good idea to remove the ninhydrin reagent please go to Section 4.

Section 1 (For Biochrom 20 Control Software (Version 3.02 or higher) users.)

At the end of a sample list there are three options for the shutdown procedure - Flush, Standby and Holiday Modes (see Section 3).  If the instrument is going to remain unused for a few days (e.g. over a weekend) and the instrument might be needed at short notice it is advisable to set up the Standby Mode at the end of the sample list so that the pumps are cycled and the coil and column are heated ready for a quick start up.

If the instrument is going to be unused for over a week then it is better to set up the Holiday Mode at the end of the sample list which enables the buffer pump to be cycled over a longer period.  In this case the ninhydrin reagent should be removed (and stored at 4ºC) as described in Section 4.

If the instrument is to remain shutdown for a period greater than one month then it is advisable to also perform remove columns, reagents as described in Section 2.

Section 2 (Shutting down instrument (removing column, reagents etc))

If the instrument is going to remain shutdown for a period greater than one month then the following should be performed:

1. Remove the analytical column and the prewash column (store at 4ºC ) and link the inlet and outlet pipes.
2. Replace the buffers with distilled water and pump each through the system.
3. Switch off the photometer lamp and the reaction coil.
4. For an Autoloader System make sure that the capsules are stored as described in AAA FAQ (How should I store my capsules?).  If the refrigeration unit is to be disconnected it must be defrosted and the excess water removed from the cabinet.

Section 3 (Standby / Holiday programs)

The Sample List Editor has an END line at the bottom of any sample list loaded and will display Flush by default to show that at the end of the Sample List the instrument will go through the automatic shutdown routine.  Double clicking on the End line will open the Post Run Mode Dialogue Box (see fig. 1) which enables one to change the post run mode.

Flush Mode - the instrument automatically shuts down:- switching of the coil and the ninhydrin pump, setting the column temperature to 37°C; then pumping buffer 1 for several minutes before switching off and the coil flush operating automatically.

Standby Mode - this allows the instrument to be left in a quick start mode, for example, over a weekend.  The column and coil temperatures will be set and selected buffers will be pumped for a defined duration (in minutes) over a chosen cycle duration (in hours).  Clicking on Setup will open up the Post Run Parameters Dialogue Box for this mode (see Fig. 2) and enable the various parameters to be set.

Holiday Mode - this allows the buffer pump and valves to be operated over a sustained shut down such as over a holiday period.   The coil is switched off (and it is recommended that the ninhydrin reagent is removed and stored at 4°C and the line flushed with water) but the column temperature is set and the selected buffers pumped for a defined duration over a chosen cycle duration (which is usually longer than that under Standby Mode).  Clicking on Setup will open up the Post Run Parameters Dialogue Box for this mode (see Fig. 3) and enable the various parameters to be set.

Section 4 (Removing the ninhydrin reagent)

To remove the ninhydrin reagent from the system the following should be performed:

1. Remove the ninhydrin reservoir and replace with a reservoir of distilled water.
2. Store the ninhydrin reservoir and any remaining contents at 4°C
3. Start pumping buffer 1, set the ninhydrin valve to DRAIN and start the ninhydrin pump. After 20 minutes set the ninhydrin valve to REACTOR and pump distilled water through the reaction coil for 15 minutes.

When the ninhydrin reagent is replaced after storage it is advisable to make sure there is no oxygen present by again de-gassing with nitrogen.