You can adjust the spray direction to maximize sensitivity and robustness. Typically, you adjust the spray direction while optimizing the API source parameters for the analytes. The position of the spray insert needle is controlled by adjustment knobs on the API source housing.

The following figure shows the adjustment knobs on the OptaMax Plus ion source.

Figure OptaMax Plus ion source
12324
No.DescriptionNo.Description

1

Front-to-back adjustment knob

3

Depth adjustment lever and locking thumbscrew

2

Retainer knob to secure the spray insert

4

Side-to-side rotational adjustment knob

 

The spray direction adjustments are described as follows:

 

Front-to-back Position

The following figure shows the front-to-back adjustment marks on the left and right side of the source housing.

Figure Front-to-back adjustment marks

You can adjust the spray direction from front-to-back over a range of -2 mm to 10 mm (12 mm total). The spray is the closest to the entrance of the MS at the -2 mm position and is farthest from the entrance at the 10 mm position.

The top-left side of the source housing has the following positions engraved:

  • 0 mm: (H-ESI mode) Use this position to calibrate the MS and for low liquid flow rates of less than 50 µL/min.
  • 5 mm: Use this position for liquid flow rates greater than 50 µL/min.
  • 10 mm: Use this position for enhanced robustness (that is, when you use a biological matrix, as one example).

The top right-side of the source housing has the following positions engraved:

  • HESI: This position is equivalent to 0 mm.
  • APCI: This position is equivalent to 2.5 mm.

 

Side-to-side Position

The following figure shows the side-to-side adjustment marks that are engraved on the top front-side of the source housing. There are two sets of marks.

Figure Side-to-side adjustment marks

You can adjust the spray direction from side-to-side over a range of ±3 degrees. The adjustment marks represent the left, center, and right positions. The spray is closest to the entrance of the MS at the center position.

 

Depth Adjustment Position

The following figure shows the depth adjustment marks that are engraved on the top of the probe.

Figure Depth adjustment marks

You can adjust the probe depth position using an adjustment range between low and high. The adjustment marks represent the low (L), low-medium, medium (M), medium-high, and high (H) positions.

NOTE

A position between low and medium is suitable in most cases. When using APCI mode and high flow rates, use a depth position between medium and high.