Flow Injection Analysis orSegmented Flow Analysis –

which method to use foryour application

William LippsMarket Specialist – Water Analyzer Products

Why do laboratories automate?

• Automationincreasesproductivity

• Automationdecreases laborcost

• Automationincreases day today reproducibility

When laboratories should notautomate

• it takes more time and effortthan it did before youautomated

Analytes that can be measuredusing automated chemistry

• Alkalinity• Ammonia• Chloride• Nitrate• Nitrite• Nitrogen, Total

Kjeldahl (TKN)• Cyanide

• Phenolics• ortho-

Phosphate• Total

Phosphorus• Silica• Sulfide• Sulfate

Laboratory costs that can bereduced by automation

Laboratory Cost

10 – 20 %OperationalSupplies

7 – 12 %Indirect Labor

20 – 28 %Direct labor

Reagent usage is decreased byautomation

0

5

10

15

20

25

ManualMethodsFlow Methods

DiscreteMethods

Milliliters

Waste generation is decreased byautomation

0102030405060708090

100

ManualMethodsFlow Methods

DiscreteMethods

Milliliters

The potential profit and cost savingsis high using automated methods

$ 10, 360$100Potential Profit

$25$25Per Test Price

48010Capacity (day)

$37.5$150Labor + OH

14Labor hours

$15$15Wage

OIA 1677CATC

The grand daddy of automation isthe continuous flow analyzer

• Segmented Flow Analysis (SFA)– 1954 by Leonard Skeggs– Technicon Autoanalyzer – introduced

1957

• Flow Injection Analysis (FIA)– About 1975 by Ruzika and others– Perstorp Tecator

All continuous flow analyzers havecommon parts

• Autosampler• Peristaltic Pump• Chemistry Cartridge• Flow through Detector• Signal Processor

Segmented Flow Analysis (SFA) - thefirst wet chemistry automation tool

• Established, mature technique• Multiple methods in literature and

as approved regulatory testmethods.

Sample is pumped into a segmentedcontinuous stream of reagent

R2

Sample/Wash

AIR

Det

WasteR1

Waste

Sample + Wash Pumpedinto Tubing

Pump

Flow Injection Analysis wasintroduced as an alternative to SFA.

• An acceptable alternative to SFAmethods.

• Multiple literary references, ATPapprovals.

Sample is injected into a continuousstream of reagent

CARRIER

R1

WasteR2

DET

Sample

Mixing

Sample does not passthrough pump

SFA and FIA are both continuous flowmethods

• narrow bore tubing, mixing coils,and finally a detector.

• reaction is determined by theconfiguration and placement of thetubing the sample and reagentspass through.

Comparison between SFA and FIA

ValveInjection intoflowingstream

Peristalticpumping intoflowingstream

SampleIntroduction

0.020 – 0.034”0.034 – 0.050”Conduits

Non-Segmented

SegmentedReagent System15 minutes15 minutesStartup time

FIASFA

Comparison between SFA and FIA

< 1%< 1%Reproducibility

rarelyAlmost alwaysSteady State

ControlledDispersion

“end over end”(inversion)

Sample mixing

30 - 120/hour30 - 120/hourSample rate

20 – 2500 ul20 – 500 ulSample VolumesFIASFA

Comparison between SFA and FIA

15 minutes15 minutesShutdown

yesyesDialysis/Gasdiffusion

< 2 minutespreferred

Up to 20minutes or more

Incubation Times

FIASFA

Reasons to use a continuous flowanalyzer

• Method requires it• Eliminate interferences• Decrease manual labor• Lower your MDL

Choosing between FIA and SFA isnot personal preference

• use the best approach for theintended purpose

• methods must be adapted to suit thetechnique chosen– Redox reactions require long contact

times– Exposure to air causes extraneous

results

There are some methods best by FIAand some best by SFA

• Some flow methods cannot be doneas well by FIA– Dialysis– Distillation

• Some flow methods cannot be doneas well by SFA– Gas diffusion– Alkalinity

SFA has significant detection limitadvantages with dialysis methods

FIAMDL (mg/L)

SFAMDL (mg/L)

Analyte

0.10.02PO4

0.050.004NO3/NO2

0.20.01NH3

SFA has a significant throughputadvantage in in-line distillation

FIASamples / hour

SFASamples / hour

Analyte

1733Phenol

17*30CN

* Competitor data

Reaction rates are independent ofthe technique used

• Reaction rates are determined by thetemperature and concentration of thereagents.

• The rate of a color reaction is thesame whether by FIA or SFA.

Matrix interferences could cause FIAresults to be biased low.

Standards inDI water

Sample matrix

FIA SFA

When to use SFA or FIA is based onoptimum method performance

• FIA– Full color in < 2 minutes– Simplicity– Ease of Use

• SFA– More than 2 minutes for reaction– Complex matrices– Dialysis– On-line distillations / digestions

We will help you choose the best auto-analyzer for you.

• Depends entirely upon yourapplication.

• We will determine the optimumsolution for you.

• We assume you desire to automatesome aspect of your laboratory.

OI flow analyzers are capable of SFAand FIA on the same instrument

• User flexibility• Modular design• Increased capability• Low operating cost

Multiple channel instruments shouldrun every channel at the same time

SFA cartridges traditionally use glasscoils

A SFA cartridge A broken glass coil

Plastic cartridges that do not break;both SFA and FIA

• Flow IV cartridge

• FS3100 cartridge

Pins

Plastic cartridges are easier tointerchange than glass

• Reagentconnections – Luerlock

• Mixing coils– Nut and ferrule– Teflon or EVA

Comparison of SFA and FIA on theOI FS3100

2 - 42 - 3Reagent(mL)

< 2%< 2%RSD30 - 12040 - 90Sample/hour

1 - 2minutes

10 minutesMax delaytime

~200 µL~200 µLVolumelooptimeSample introFIASFA

Method comparison of SFA and FIAon the FS3100

FIAthroughput

FIAMDL

SFAthroughput

SFAMDL

Analyte

600.001450.001PO4

600.002550.0005NO3/NO2

510.002720.003NH3

OI Flow methods enjoy a largecalibration range

FIA CalibrationRange (mg/L)

SFA CalibrationRange (mg/L)Analyte

0.01 – 5.00.01 – 2.0PO4

0.005 - 100.005 - 10NO3/NO2

0.01 - 200.01 - 25NH3

Choosing between SFA and FIA bylaboratory requirement

Simple Chemistry Minimal Training Ability to AddModules Later

Complex andVariable Matrices

SFAFIA