YSI 5905 Operating Manual

YSI 5905, 5010,
200-BOD, and
Pro-BOD Probe
Instruction Manual

TABLE OF CONTENTS

I

NTRODUCTION ................................................................ 1

OPERATING PRINCIPLES .......................................................2

USING THE PROBE ............................................................. 3

Changing the Membrane Cap....................................................3

Warm Up.....................................................................................5

Electrode Cleaning...................................................................... 5

OPERATING PROCEDURES AND PRECAUTIONS ............................ 7

Air Calibration ............................................................................7

Checking the Probe Zero............................................................ 7

Membrane Life............................................................................ 7

Interferences................................................................................ 8

Acids ............................................................................................ 8

Erroneous Readings.................................................................... 8

Storage......................................................................................... 8

PROBLEM SOLVING ............................................................ 9

Trouble Shooting Guide.............................................................9

SERVICING..................................................................... 11

WARRANTY AND REPAIR ..................................................... 13

Authorized Service Centers...................................................... 14

Cleaning Instructions ...............................................................14

Packing Instructions................................................................. 15

PROBE SPECIFICATIONS .....................................................17

APPENDIX A ................................................................... 18

APPENDIX B ...................................................................19

i

INTRODUCTION

The YSI Model 5905/5010/200-BOD/Pro-BOD (Biochemical
Oxygen Demand) probe is used for measuring dissolved oxygen
in all popular size BOD bottles. These probes feature self stirring,
easily replaceable membrane caps, and a refurbishable electrode
system.

The 5905 probe is designed for use with all YSI grey-box-style
dissolved oxygen meters, except for the Model 55 or Model 550A.
It must be used with an adapter (5011) in order to be used on the
Model 5000 and 5100 bench top instruments.

The 5010 probe is specifically designed for use with the Model
5000 and 5100 only.

The 200-BOD probe is specifically designed for use with the
Model DO200 only.

The Pro-BOD probe is specifically designed for use with the
Pro20 and Professional Plus instruments.

This manual also applies to probes 5905-J, 5905-K, 5905-L, 5905­W (Appendix A), and probes 5010-J, 5010-K, 5010-L, and 5010­W (Appendix A)

---IMPORTANT---

Intended Use

The 5905/5010/200-BOD/Pro-BOD probe is intended for
laboratory use, not field use. It is not waterproof and should
never be immersed past the taper on the stem of the probe.

1

OPERATING PRINCIPLES

The 5905/5010/200-BOD/Pro-BOD probe is a polarographic
dissolved oxygen sensor. An oxygen permeable membrane covers
an electrolytic cell consisting of a cathode and an anode. This
membrane acts as a diffusion barrier and an isolation barrier
preventing the fouling of the cathode surface by impurities in the
environment. The cathode is the gold electrode, and the anode is
the silver electrode which completes the electrolytic cell and acts
as a reference electrode.

Upon entering the cell through the membrane, oxygen is reduced
at an applied potential of -0.8 V referenced to the silver electrode.
The reduction current at the cathode is directly proportional to
the partial pressure of oxygen in liquid (expressed as %-air
saturation) which is also proportional to the concentration of
dissolved oxygen (in mg/L) at a particular temperature. Thus the
same partial pressure of oxygen (%-air saturation) in liquid gives
different concentrations of dissolved oxygen (mg/L) at different
temperatures because of the different solubilities of oxygen at
different temperatures.

2

USING THE PROBE

The 5905/200-BOD/Pro-BOD must be plugged into a YSI meter
and the stirrer power plug must be plugged into its power
adapter. The 5010 must be plugged into a YSI meter only, as it
gets its stirring power from the 5000/5100 instrument.

Changing the Membrane Cap

---IMPORTANT---

New Probe Use

New probes are shipped with a dry membrane cap to protect the
electrodes. A new membrane cap must be installed before first
use. For the 5905/5010, use a Teflon membrane from a 5906
Membrane Kit. For the 200-BOD/Pro-BOD, use a PE membrane
from a 5908 Membrane Kit.

Follow these instructions to change membrane caps (Figure 1):

1. Remove the stir paddle from the probe by pulling it straight
out.

2. Unscrew the old membrane cap from the probe. Before
installing a new membrane, clean the probe tip with deionized
water in order to remove any contaminants.

3. Hold the membrane cap and fill it at least ½ full with the
electrolyte solution provided. Screw the membrane cap onto
the probe moderately tight. A small amount of electrolyte
should overflow.

4. Rinse off excess electrolyte from the probe with deionized
water.

5. Reinstall the stir paddle.

3

Remove

Stir Paddle

Fill Membrane Cap

with Solution

Unscrew Cap

Replace

Stir Paddle

Screw Cap on

moderately tight

Figure 1: Membrane Installation on the 5905/5010/200-BOD/Pro­BOD .

4

Warm Up

Every time the instrument is turned on, the 5905/5010/200­BOD/Pro-BOD Probe must be allowed to warm up for about 10­20 minutes before taking the first reading. This allows the probe
to use up all the oxygen retained in the cap.

---IMPORTANT---

New Probe Break In (motor off)

For best results, please allow the probe more than the usual 20
minutes to warm up after the first membrane is installed. The
process may be faster if the probe is allowed to warm up in a
BOD bottle filled with clean water. If possible, it’s a good idea to
let new probes warm up overnight (with a new membrane and
KCl) prior to first use.

Electrode Cleaning

The 5905/5010/200-BOD/Pro-BOD should be cleaned only when
erratic readings occur or after about every 500 hours of use (two
months). Each cleaning removes material and reduces the life of
the probe, so excessive cleaning should be avoided.

Gold Cathode

For correct probe operation, the gold cathode must be textured
properly (for its location, see figure 2). It can become tarnished
or plated with silver after extended use. The gold cathode can be
cleaned by using the sanding disc provided in the 5906 and 5908
Membrane Kits. Place the disc in the palm of your hand, then
sand the gold with a twisting motion about 3 times or until all
silver deposits are removed and the gold appears to have a matte
finish. If the cathode remains tarnished, return the probe for
service.

5