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Automating Wet Chemical Analysis

William Lipps Market Specialist for Water Analyzer Products

December 11, 2008

The advantages of automating wet

chemical analysis.

• Save time

• Decrease cost

• Improve quality

• Reduce waste

• Do more samples

• Do more samples

• Do more samples

The benefits of automating wet

chemical analysis

The economic advantage of

automation is greater throughput.

More Samples = More Money

“Silent Hours” – 3X Throughput

The simplest forms of automation are

now common laboratory tools.

• Magnetic stirrer

• Auto filling burettes

• Vacuum filtration

• Bottle top dispensers

Almost any chemistry can be

automated.

• Alkalinity

• Ammonia

• Chloride

• Nitrate

• Nitrite

• Nitrogen, Total

Kjeldahl (TKN)

• Phenolics

• ortho-

Phosphate

• Total

Phosphorus

• Silica

• Sulfide

• Sulfate

Automate the labor intensive

extractions and digestions.

• Digestion

• Distillation

• Solvent extraction

• Gas diffusion

• Dialysis

Make your life easier by automating

time consuming, manual methods.

Detector

Automated methods should be easy

and obtain better results.

• “easy-to-use”

• Better results

• Lower cost per test

Potential profit and cost savings is

high.

CATC OIA 1677

Wage $15 $15

Labor hours 4 1

Labor + OH $150 $37.5

Capacity (day) 10 480

Per Test Price $25 $25

Potential Profit $100 $ 10, 360

Two important questions to answer

before choosing an analyzer.

• Will I have a lot of samples for the

same tests?

• Or, will I have a lot of tests for a few

samples?

Two important automated chemistry

technologies.

Automated Wet Chemistry

SFA FIA Discrete

Continuous Flow Robotic

Continuous flow analyzers move liquid

continuously through tubing.

• Continuous flowing stream

• Mixing coils

• Detector

Segmented Flow Analysis minimizes

dispersion with air bubbles.

• Original Automated Analyzer

• Approved in regulatory test methods

The air bubbles minimize carryover

from one segment to the next.

The air segments ensure mixing and

maximum color formation.

The limited dispersion results in

rectangular peaks with flat tops.

Summation of Multiple Segments

A real example of segmented flow

peaks

Segmented flow limits dispersion

and enables steady state reactions.

• Low MDL

• Excellent Precision

• Steady state reactions

• Limited dispersion

• High throughput

• Easily expandable

Flow injection analysis injects sample

into an unsegmented stream.

Flow injection does not segment with

air and sample mixes by dispersion.

The FIA peak is shaped like a bell

curve.

Example of real FIA peaks

Flow injection analysis has high

throughput and is easy to use.

• High throughput

• Excellent Precision

• Ease of use

• No de-bubbling

• Rapid startup and shutdown

Segmented flow peaks reach

steady state and maximum color

SFA allows longer reactions for greater

color; FIA has greater throughput.

SFA FIA

Sample intro time loop

Volume ~200 µL ~200 µL

Max delay

time

10 minutes 1 - 2

minutes

Sample/hour 40 - 90 30 - 120

RSD < 2% < 2%

Reagent

(mL)

2 - 3 2 - 4

* OI Analytical FS 3100

Use Continuous Flow Analysis (CFA)

when you have a lot of samples to run.

• Choose CFA when automating a lot

of samples for a few tests!

• Exception – CNSolution

– No distillation makes CN analysis

economical regardless of sample

load

What is a Discrete Analyzer?

• Reactions in individual cuvettes

• Mixing within the cuvette

• Measurement within the cuvette

A discrete analyzer is a multi-

chemistry analyzer

• Batch Selective Analysis

• True Random Access

• Automatic Method Interchange

• “Hands off” operation

A discrete analyzer simplifies

automated chemistry.

A discrete analyzer uses cuvettes

instead of pump tubes

• Sample dispensed into cuvette

• Sample is blanked

• Reagents added to sample

• Sample incubates in cuvette

• Instrument measures absorbance

• Result calculated

The cuvette contains each individual

reaction.

• No peaks – single absorbance

reading

• No interaction between samples

• Equilibrium reactions (maximum

color)

Startup is easy because there are

no pump tubes or flows

• Reduces Turn-Around-Time

• Unattended Operation

• Only runs requested tests

• Standards Prepared Automatically

• Automatically Dilutes over-range samples

• No pump tubes

Use discrete analyzers for widely

differing matrices and daily routines.

• Choose discrete when automating a

few samples for a lot of tests.

• Choose a discrete analyzer when

running a variety of matrices, or

parameters.

CFA methods are faster than discrete

methods.

Discrete CFA

Reagents per test Continuously

flowing

Carryover None Need wash

solution

Throughput Function of #

reagents

Determined by

peak width

Discrete analyzers can run any method

without operator intervention.

Discrete CFA

Sensitivity Standard

Detector

ER Detector

# Tests per

run

Limited by

programming

Limited by #

detectors

Fluid System Disposable

cuvettes

Pump tubes

Discrete analyzers require almost no

maintenance

Discrete CFA

Operator

maintenance

Limited Change

pump tubes

Initial setup

per test

none 5 – 10

minutes

Final

teardown

per test

none 5 – 10

minutes

OI Automated Analyzers cover all

needs

FS IV FS3100 DA3500

Mode Continuous

or batch

Continuous

or batch

Batch

Selective no no yes

Random no no yes

Fast yes yes no

Choose an automated chemistry based

on your needs

• The technique to use depends on:

– Sample load

– Tests per sample

– Analytical Requirements (MDL,

etc)

• Make educated choice on what is

best for your application

For Additional Information

Questions and Comments?

Please visit our website at:

www.oico.com