OHAUS ACROSS PRO AO-2 User manual

ACROSS PRO
Digital Adjustable
Manual Microliter Pipette
Micro Pipeta de Volumen Variable
Réglable numériquement
Manuel de la pipette Microliter
AO-2
AO-10
AO-20
AO-100
AO-200
AO-1000
AO-5000
AO-10ML
AO8-200
9 models for volume ranges from 0.1 μL to 10 mL
9 modelos para rangos de volumen de 0.1 μl a 10 ml
9 modèles pour des gammes de volumes de 0,1 µl à10 ml

ACROSS PRO
Digital Adjustable Manual Pipettes
CONTENTS
Description………………...……………………………………………………....1
Contents………………………..………………………………………………….2
Autoclaving…………………………..…………………………………………....2
Volume Indicator...........................................................................................2
Safety Filter, AO-5000 & AO-10ML...............................................................3
Operation......................................................................................................3
Tips Selection................................................................................................5
Tips Immersion Depth...................................................................................5
Pipetting Guidelines & Precautions...............................................................6
Pre-Rinsing Recommended..........................................................................6
Reverse Mode Pipetting................................................................................6
Pipetting Liquids of Varying Density..............................................................7
Temperature Considerations.........................................................................7
Acids and Corrosives....................................................................................7
Storage..........................................................................................................8
Maintenance………………………...…………................................................8
Calibration.....................................................................................................8
Warranty .......................................................................................................9
Removing/Replacing Tip Ejector Arm...........................................................9
TipEjector.................................................................................................. ...9
Performance Specifications........................................................................10
Replacement Parts / Accessories……………..………………………………11
FIGURES
Figure 1 ACROSS PRO AO-200……...………………….……………….……..1
Figure 2 Operating ACROSS PRO ……………..……………………………..4
Figure 3 Pipette Stand…………………….………..........................................8
Figure 4 Removing Tip Ejector Arm…………………………………………….9
Figure 5: Cam-actuated Tip Ejector…………………………………………. 10
DIAGRAMS FOR REPLACEMENT PARTS
Models AO-2, AO-10, AO-20, AO-100…….................................................12
Models AO-200, AO-1000, AO-5000, AO-10ML, AO8-200....................13 14
TABLES
Specifications…….......................................................................................10
Prices and specifications are subject to change without notice.

Digital volume indicator
Coupling nut
Shaft
Friction Ring/
Volume Adjustment
Precision Micrometer
Description
Nine models of ACROSS PRO continuously adjustable digital pipette cover
the entire volume range from 0.1μl to 10ml.
Piston stroke is set by adjusting a micrometer coupled directly to a digital
volume indicator, which reads in microliters.
All Ohaus ACROSS PRO models have a highly polished stainless steel
piston, polyethylene/Teflon seal and o-ring (except AO-10ML, which uses a
grease seal). ACROSS PRO requires no routine lubrication and will give
years of trouble-free service.
A plastic tip ejector is provided with all models (except AO-5000 and AO-
10ML) for safe disposal of used tips.
Figure 1. ACROSS PRO AO-200
Plunger Button/
volume adjustment
Tip ejector button
(except AO-5000
and AO-10ML)
Tip ejector arm
(except AO-5000
and AO-10ML)
High-impact,
low thermal
conductivity
body
1

Contents
ACROSS PRO Sample tips
Instruction Manual Test report / Warranty Card
Autoclaving
The Shaft and tip ejector are autoclavable: 121℃, 1 atm, 15-20 minutes).
(AO-5000, AO-10ML do not use tip ejectors.)
Volume Indicator
The volume indicator is read from top to bottom. Up to AO-200 black digits
indicate microliters and red digits tenths and hundredths of microliters. For
AO-1000 and AO-5000，red digits indicate milliliters and black digits
microliters. For AO-10ML, black digits indicate milliliters and red digit tenths
of a milliliter.
AO-2 AO-10 AO-20 AO-100 AO-200 AO-1000 AO-5000 AO-10ML
1
0
1
0
1
0
1
0
2
7
2
7
2
7
2
7
5
5
5
5
5
5
5
5
1.25 µL 7.5 µL 12.5 µL 75 µL 125 µL 750 µL 1.25 mL 7.5 mL
Sample values, volume ranges, and smallest increments for each ACROSS
PRO model are shown below:
Model Range (μL) Recommended (μL) Min. Increment (μL)
AO-2 0 to 2 0.1 to 2 0.002
AO-10 0 to 10 0.5 to 10 0.02
AO-20 0 to 20 2 to 20 0.02
AO-100 0 to 100 10 to 100 0.2
AO-200 0 to 200 20 to 200 0.2
AO-1000 0 to 1000 100 to 1000 2.0
AO-5000 0 to 5000 500 to 5000 2.0
AO-10ML 0 to 10mL 1mL to 10mL 20.0
AO8-200 0 to 200 20 to 200 0.2
2
Black Digits
Red Digits

Safety Filter, AO-5000 and AO-10ML
Models AO-5000 and AO-10ML use a safety filter in the shaft to help
prevent liquid entering the shaft and contacting the piston, if the plunger
snaps up during aspiration. This is particularly important using large
volumes. If the filter gets wet, replace it.
For AO-5000 insert the small diameter into the shaft, for AO-10ML insert
the large diameter into the shaft. Part number: 30079146 (pack of 100).
Operation
1. Turn the plunger button or the volume adjustment knob until the
volume indicator is 1/3 revolution above the desired setting, then turn
slowly clockwise until the desired volume shows on the indicator.
2. ALWAYS dial down to the desired volume. This prevents mechanical
backlash from affecting accuracy. If you pass the desired setting, turn
the dial 1/3 revolution higher than desired and dial down to reset the
volume. The friction ring prevents unintentional volume changes.
3. Attach a new disposable tip to the pipette shaft. Press into the volume
displayed on the indicator.
4. Holding Across PRO vertically, immerse the tip into the sample to
the proper depth; see table on page 5.
5 Allow the pushbutton to return slowly to the UP postion. Never let it
snap up! See figure 2A.
6. Pause briefly to ensure that the full volume of sample is drawn into
the tip.
END OF
5000 µL SHAFT
3
END OF
10 ML SHAFT

7. Withdraw the tip from the sample liquid. If any liquid remains on the
outside of the tip, wipe it carefully with a lint-free tissue, avoiding the
tip orifice.
8. To dispense sample, touch the tip end against the side wall of the
receiving vessel and depress the plunger slowly to the first stop. See
Figure 2B.
Wait 1 second: AO-2 ~ AO-200
1-2 secs: AO-1000
2-3 secs: AO-5000, AO-10ML
(Longer for viscous solutions).
Then press the plunger to the SECOND STOP (bottom of stroke),
expelling any residual liquid in the tip. See Figure 2C.
9. With the plunger fully pressed, withdraw the pipette from the vessel
carefully, with the tip against the vessel wall.
10. Allow the plunger to return to the up position.
11. Discard the tip by depressing the tip ejector button. A fresh tip should
be used for each sample to prevent sample carryover.
Figure 2. Operating ACROSS PRO
TOP OF STROKE
1st STOP
2nd STOP
A
B
C
4

Tip Selection
Tips must seal properly on the shaft to assure an air-tight seal and
avoid leaks or poor accuracy.
Tips must be soft and flexible so that the shaft is not scratched or
worn prematurely.
The tip orifice must be the correct size, and orifice size and
geometry must be consistent from tip to tip. Otherwise, accuracy
and precision will be affected.
Interior and exterior surfaces must be clear, smooth, and
hydrophobic to avoid retention of liquid. Too much retention results
in poor accuracy and reducibility.
Specified performance is guaranteed only when OHAUS disposable
tips are used as recommended in this manual.
OHAUS cannot accept responsibility for poor performance resulting from
the use of tips by other manufacturers. OHAUS tips are molded from
premium-grade virgin polypropylene plastic. Samples from each lot of tips
are inspected microscopically to ensure that every lot meets OHAUS’s high
standards.
Tip Immersion Depth
The recommended depth for tip insertion into the sample for each ACROSS
PRO model is shown in the table below:
Model Immersion Depth
2 - 10 μL 1 –2 mm
20 - 100 μL 2 –3 mm
200 - 1000 μL 3 –6 mm
5000μL –10 ml 6 - 10 mm
Tip immersion depth is important. If exceeded, the volume measured will be
inaccurate, possibly out of specification.
Tip angle is also important. Hold the pipette vertically, or within 20 degrees
of vertical.
5

Pipetting Guidelines＆Precautions
Consistency in all aspects of pipetting will significantly contribute to
optimum reproducibility.
1. Consistent pickup/dispense rhythm while pipetting.
2. Consistent speed and smoothness when you press and release the
pushbutton.
3. Consistent pushbutton pressure at the first stop.
4. Consistent immersion depth.
5. Minimal angle (＜20°from vertical)
6. Never invert or lay the pipette down if liquid is in the tip.
Pre-Rinsing Recommended
Some solutions (e.g. serum, protein-containing solutions, and organic
solvents) can leave a film on the inside tip wall, resulting in an error larger
than the tolerance specified. Since this film remains relatively constant in
successive pipetting with the same tip, excellent precision may be obtained
by refilling the tip and using the refilled volume as the sample. Successive
samples from this same tip will exhibit good reproducibility.
Reverse Mode Pipetting
Reverse mode pipetting is recommended for highly viscous, biological or
foaming liquids, or very small volumes of liquid.
1. Mount a disposable tip on the pipette shaft.
2. Press the pushbutton fully to the second stop.
3. Immerse the tip in liquid and return the plunger slowly to the full up
position. Wait a moment for the liquid column to reach equilibrium in the
tip.
4. Wipe any excess liquid from outside of the tip without
touching the orifice.
5. To dispense, rest the end of the tip against the vessel
wall and press the plunger to the first stop only. Hold at
the first stop for a few seconds-long enough for the liquid
column to reach equilibrium again.
6. Remove the tip from the receiving vessel without blowing
out the remaining liquid.
7. Return excess sample in the tip to the original sample
container, if desired. Discard the used tip.
6

Pipetting Liquids of Varying Density
ACROSS PRO let’s you compensate for solutions of density much different
from water, by setting the volume slightly higher or lower than that required.
The compensation amount must be determined empirically.
E.g., if pipetting 10μl of CsCl solution, you determine that the volume
delivered is actually 8.5 μl (average of 5 samples). Try increasing the
volume setting to 11.8μl and repeat the measurements. If the volumes
delivered are still not close enough to 10μl, make another slight volume
adjustment until the measurements are as desired.
Very dense liquids may not be suitable for air displacement pipetting.
Temperature Considerations
Warm or cold liquids can be measured with good precision by using a
consistent pipetting rhythm. This will help minimize any differences in
heating or cooling effects within the pipette. Use a new tip each time for
best accuracy and precision when measure samples with temperatures
greatly different from ambient, and do not pre-rinse. You will get best
results if there is no delay between picking up the
sample and dispensing it.
If working in a cold room, allow the pipette to stabilize at ambient
temperature before operation.
Acids and Corrosives
After pipetting concentrated acids or highly corrosive solutions, you should
disassemble, inspect and clean (if necessary) the piston, shaft, and seal
assemblies.
Extensive contact with corrosive fumes may corrode the piston. This will
result in premature seal wear and may require refinishing or replacement of
the piston. Exposure of internal components to corrosive fumes can be
reduced by using aerosol-resistant tips. These tips have an internal filter
which acts as an aerosol barrier.
7

Storage
ACROSS PRO is a precision instrument and should be treated with the level
of care appropriate for laboratory instrumentation. A stand is available to
hold ACROSS PRO securely when not in use.
Figure 3. Pipette stand
Maintenance
1. Selecting optimized volume ranges, setting the volume by rotating the
operating button, do not rotate the operating button outside the volume
range of the pipette.
2. Tips need to be changed with different samples.
3. Pre-rinse the new tip before aspirating the liquid by filling and emptying
the tip for three to five times.
4. To avoid contamination, do not rest the pipette on its side horizontally
especially with the tip attached.
5. For convenience and safety always keep the pipette vertically on its
hanger when not in use.
Calibration
Each ACROSS PRO is factory calibrated and carefully checked
gravimetrically before shipment using distilled water and an analytical
balance. The test room shall have a constant (±0.5℃) temperature. Water
temperature is stabilized at 21.5±1℃.Use an analytical balance with a
readability of 0.1mgs or 0.001mgs.
8

Warranty Information
ACROSS PRO pipettes are covered by warranty for 1 year against defects
in materials and workmanship. Any warranty will, however, be deemed as
void if fault is found to have been caused by maltreatment misuse,
unauthorized maintenance of service or negligence of regular maintenance
and service, accidental damage, incorrect storage or use of the ducts for
operations outside their specified limitations, outside their specifications,
contrary to the instructions given in this manual or with other than the
manufacturer’s original tips.
Removing / Replacing Tip Ejector Arm
Figure 4. Removing the Tip Ejector Arm
Removing the Tip Ejector Arm
1. Press and hold the tip ejector fully down.
2. With the other hand, pull the tip ejector arm straight down.
Tip Ejector
Figure 5: Cam-
actuated Tip Ejector
Ohaus ACROSS PRO AO8-200 has a cam-
actuated tip ejector which consists of an eject
rake moving under action of a double cam. The
cam is activated by turning the winged tip ejector
knob 45°in either direction then releasing the
knob. A bearing follows the cam and decreases
friction to provide smooth, efficient removal of all
eight tips.
CAUTION:
Do not take the ejector mechanism apart.
Fasteners on the inside of the mechanism have
been permanently secured. If disassembled,
reassembly will be impossible.
Hold the handle with
one hand and the tip
ejector in the other
hand.
1
Pull the Tip
Ejector Arm off
2
9

Performance Specifications
Each ACROSS PRO is factory calibrated and carefully checked
gravimetrically before shipment using distilled water and an analytical
balance. Water temperature and ambient conditions are stabilized at
21.5±1℃.Volumetric corrections are made for both the density of water and
evaporation where applicable.
When used in accordance with the pipetting procedures in this manual and
with OHAUS tips, ACROSS PRO pipettes will perform to the following
specifications.
Model
Volume
µL
Increment
µL
Accuracy
Precision
%
µL(±）
%
µL(≤）
AO-2
0.2
12
0.024
6
0.012
1.0
0.002
2.7
0.027
1.3
0.013
2.0
1.5
0.030
0.7
0.014
AO-10
1
2.5
0.025
1.2
0.012
5
0.02
1.5
0.075
0.6
0.03
10
1
0.1
0.4
0.04
AO-20
2
0.02
7.5
0.15
2
0.04
5
3
0.15
0.9
0.045
10
1.5
0.15
0.5
0.05
20
1
0.2
0.3
0.06
AO-100
10
3.5
0.35
1
0.1
50
0.2
0.8
0.4
0.24
0.12
100
0.8
0.8
0.15
0.15
AO-200
20
2.5
0.5
1.0
0.2
100
0.2
0.8
0.8
0.25
0.25
200
0.8
1.6
0.15
0.3
AO-1000
100
3
3
0.6
0.6
500
2
0.8
4
0.2
1
1000
0.8
8
0.15
1.5
AO-5000
500
2.4
12
0.6
3
2500
2
0.6
15
0.2
5
5000
0.6
30
0.16
8
AO-10ML
1mL
5mL
10mL
20
5
1
0.6
50
50
60
0.6
0.2
0.16
6
10
16
AO8-200
20
50
100
200
0.2
2.5
1.0
1.0
1.0
0.5
0.5
1.0
2.0
1.25
0.5
0.5
0.5
0.25
0.25
0.5
1.0
10

These manufacturer’s specifications should be used as guidelines when
establishing your own performance specification.
Specifications are subject to change without notice.
Accessories
ACROSS PRO is a precision instrument and should be treated with the level
of care appropriate for laboratory instrumentation. A pipette stand is
available to hold ACROSS PRO securely when not in use.
Replacement Parts of ACROSS PRO
Part
Model
A0-2
AO-10
AO-20
AO-100
AO-200
AO-1000
AO-5000
AO-10ML
AO8-200
A
Plunger Button
30079034
30079035
30079036
30079037
30079038
30079039
30079110
30079111
Page 14
B
Coupling Nut
30079112
30079112
30079112
30079112
30079112
30079112
n.a.
n.a.
C
Shaft
30079113
30079114
30079115
30079116
30079117
30079118
30079119
30079120
D
Tip Ejector
30079121
30079121
30079122
30079123
30079124
30079125
n.a.
n.a.
E
O-ring
30079126
30079127
30079128
30079129
30079130
30079131
30079132
30079133
Seal
n.a.
F
Large Spring
Positioner,
Small Spring
Positioner,
Small Spring,
Seal assy
holder
30079134
30079134
30079135
30079136
30079137
n.a.
n.a.
n.a.
G
Piston,
Large Spring
30079138
30079139
30079140
30079141
30079142
n.a.
n.a.
n.a.
H
Piston Assy
n.a.
n.a.
n.a.
n.a.
n.a.
30079143
30079144
30079145
N
Filter
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
30079146
30079146
See Replacement parts diagrams on page 12 - 14.
11

AO-2
AO-10
AO-20
AO-100
A
B
C
G
E
12
A
B
C
D
D
G
F
E
A
B
C
D
E
F
G
A
B
D
G
F
E
F

AO-200
AO-1000
A
B
C
D
E
F
G
A
B
B
C
D
E
A
C
E
A
C
E
H
AO-5000
13
AO-10mL
H
H

30125444
SP Nozzel 1 Unit AO8-200
30125445
SP Piston 1 Unit AO8-200
30125446
SP Nozzel 8 Units AO8-200
30125447
SP Piston 8 Units AO8-200
14
AO8-200
A

ACROSS PRO
Micro Pipetas de Volumen Variable
CONTENIDO
Descripción……………...……………………………………………………....1
Contenido……………………..………………………………………………….2
Uso en autoclave………………………..……………………………………....2
Indicador de volumen...................................................................................2
Filtro de seguridad, AO-5000 y AO-10ML....................................................3
Operación................................................................................................3
Selección de puntas..................................................................................... 5
Profundidad de inmersión de las puntas...................................................... 5
Pautas y precauciones de pipeteo...............................................................6
Pre-enjuagado recomendado.......................................................................6
Pipeteo en modo inverso.............................................................................6
Pipeteo de líquidos de densidad variable....................................................7
Consideraciones de temperatura...............................................................7
Ácidos y sustancias corrosivas................................................................7
Almacenamiento..........................................................................................8
Mantenimiento………………...…………................................................8
Calibración...................................................................................................8
Garantía ....................................................................................................9
Retiro y reemplazo del brazo expulsor de puntas....................9
Expulsor de puntas...................................................................................... 9
Especificaciones de desempeño.............................................................10
Partes de reemplazo y accesorios……………..……………………11
FIGURAS
Figura 1 ACROSS PRO AO-200……...………………….……………….……..1
Figura 2 Operación de la ACROSS PRO ……………..…………………..4
Figura 3 Soporte de pipetas…………………….………...........................8
Figura 4 Brazo de expulsión de puntas…………………………………….9
Figura 5: Expulsor accionado por leva…………………………..…………. 10
DIAGRAMAS PARA PARTES DE REEMPLAZO
Modelos AO-2, AO-10, AO-20 y AO-100….................................................12
Modelos AO-200, AO-1000, AO-5000, AO-10ML y AO8-200................13 14
TABLAS
Especificaciones…......................................................................................10
Los precios y especificaciones están sujetos a cambio sin previo aviso.