HELWAN UNIVERSITY

FACUILITY OF ENGINEERING

BIOMEDICAL DEPARTMENT

Presented By:

FATMA FATMA FATMA FATMA KAMAL KAMAL KAMAL KAMAL

HEBA ABD HEBA ABD HEBA ABD HEBA ABD ELSABOURELSABOURELSABOURELSABOUR

MAGAD MAGAD MAGAD MAGAD AHMEDAHMEDAHMEDAHMED

NASHWA NASHWA NASHWA NASHWA ADELADELADELADEL SUPERVISORS:

DR.MohamedDR.MohamedDR.MohamedDR.Mohamed EldsokyEldsokyEldsokyEldsoky

EngEngEngEng .Ahmed .Ahmed .Ahmed .Ahmed mostfamostfamostfamostfa

*Definitions

*Types of measurements*Component*Technical specifications

-Electrolytes are positively and negatively

charged molecules called ions, that are found

within the body's cells and extracellular

fluids, including blood plasma.

-Electrolytes play multiple roles in the

maintenance of body functions:

1-They sustain osmotic pressure which

control fluids distribution in the body (related related related related

to sodium levelto sodium levelto sodium levelto sodium level).

2-Maintain proper body Ph .

3-Regulate the function of the heart and

other muscles.

4- Assist in electron transfer reactions.

5- Participate in enzymatic reactions .

� Some of the disorders associated with

electrolyte imbalances include:

5-overhydrationn and dehydration.

(When When When When water water water water loss is greater than intake, or loss is greater than intake, or loss is greater than intake, or loss is greater than intake, or

vice versavice versavice versavice versa).

1-Congestive heart failure.

2-Respiratory alkalosis (occurs occurs occurs occurs when when when when

blood pH falls blood pH falls blood pH falls blood pH falls above above above above 7777....35353535), and acidosis

occurs( when blood pH falls below when blood pH falls below when blood pH falls below when blood pH falls below 7777....35353535).

3-Diabetes insipidus (water water water water loss by the loss by the loss by the loss by the

kidneyskidneyskidneyskidneys).

4-Gastrointestinal and kidney diseases.

-Because abnormal electrolyte levels can

result from or cause various disorders,

their analysis is a key factor in patient

diagnosis and treatment.

-Electrolyte Analyzers measure these

electrolytes in serum, plasma and urine.

-Doctors refer to a low electrolyte level with

the prefix “hypo_” and to a high level

With the prefix “hyper_”.

ELECTROLYTE PANEL

Electrolyte analyzers measure electrolyte

concentrations in body fluids - typically

whole blood, plasma, serum, or urine

specimens.

Electrolytes typically measured by an

Electrolyte Analyzer are called the

“Electrolyte Panel” which consists of:

- Sodium (Na+)

- Potassium (K +)

- Chloride (CL+)

-Bicarbonate(HCO3+)

-Calcium, the most abundant mineral in

the body, is also measured by many

electrolyte analyzers. The concentration

of ionized calcium (Ca++), total calcium,

or both can be measured in the same

body fluids as electrolytes.

-Sodium is the principal extracellular

cation and potassium the principal

intracellular cation. A cation is an ion

with a positive charge.

Anions have a negative charge.

AlD(2)

AlD(1) Micro_

processor

DC

motor

Peristlatic

pump

Bubble

Detector

LCDAny

Electrolyte

REF.

1-what analyte you want to measure ?

The external reference electrode and

measuring electrode are exposed to the

unknown sample solution, potential of

the sample solution is measured

relative to the external reference.

2- Buffering the voltage generated by

ion selective electrode by operational

amplifier.

3- Analong multiplexer selecting signal.

6- Digital display for showing results

and displaying messages and questions

7- The motor driver turns drives D.C

motor.

8- D .C motor drives the Peristaltic

Pump

5- Micro-processor based computer

control mechanical functions of the

analyzer.

4- An (AlD 1) converter for converting the

signal into digital domain .

9-Bubble detector verifies the presence

of air or fluid in the sample tubing.

10-An (AlD 2) converts the bubble

detector reading into digital form to

the computer.

METHODS OF ELECTROLYTIC

ANALYSIS

1-Flame Emission Photometry(FEP)

2-Ion Selective Electrode(ISE)

Flame Emission Photometry

Flame photometry can be used to measure

Na+, K+, and lithium Li+ .This method is

based on the fact that some metallic

elements absorb thermal energy, exciting

their electrons to a higher energy state .As

the electrons return to the stable ground

state, they emit photons light at

wavelengths characteristic of the particular

element and at intensities proportional to

the element’s concentration.

The concentration of the test solution

is determined by comparing its signal

with that obtained for standard

solutions.

-There is a different colored filter for

each analyte measured

-The output of the photo-detector is

directly proportional to the

concentration of the analyte being

measured.

- The brighter the flame (in in in in that that that that

wavelengthwavelengthwavelengthwavelength), the greater the

concentration of the analyte

• Sodium is yellow with a

wavelength of about 590 nm

• Calcium is red with a wavelength

of about 640 nm

-There is a different colored filter

for each analyte measured.

• Potassium is blue with a

wavelength of about 490 nm

• Lithium is dark red with a wavelength

of about 710 nm

-The output of the photodetector is

directly proportional to the

concentration of the analyte being

measured

-The brighter the flame in that

wavelength, the greater the

concentration of the analyte

Each analyte emits a specific color

when burned.

Reported problems

Flame photometry measurements can be

compromised when insufficient attention

is paid to maintenance procedures,

optimal flame size, and aspiration rate .In

addition, a warm-up period is usually

required to stabilize the system .Because

of the gas used to fuel the system, flame

photometry systems should be used in a

well-ventilated area.

Problems can arise when results from

methods using direct measurements

undiluted specimens are compared with

those from methods using indirect

measurements diluted specimens .Flame

photometry provides an indirect

measurement of total concentration,

particularly in Na +and K +analyses, while

ISE methods provide direct measurements

of activity .

Because hyperproteinemic or

hyperlipidemic specimens have

decreased amounts of plasma water,

indirect measurements can yield

falsely lowered results.

Direct methods are not subject to

this type of error.

Ion-Selective Electrodes

(ISE)

Principles of operation

This method measures the voltage that

develops between the inner and outer

surfaces of an ion selective electrode.

Most electrolyte analyzers use ISE

methodology in which measurements

of the ion activity in solution are made

potentiometrically using an external

reference electrode and an ISE

containing an internal reference

electrode .

The external reference electrode and

ISE are exposed to the unknown

sample solution, and the potential of

the sample solution is measured

relative to the external reference

electrode .As the specific ions under

analysis are selectively bound to the

ISE, the internal reference electrode

detects the potential difference

between an internal filling solution

and the sample solution potential

The ISE system is calibrated with

solutions containing known

concentrations of analytes; the

concentration of an unknown

solution is derived by comparing

its potential with that of a solution of

known concentration .

between the external reference

electrode and the ISE, which is a

function of the specific ion’s activity

concentration, is amplified and liter

L displayed in millimoles per liter

Different types of ISEs provide

measurements for specific analytes .The

Na +- sensitive electrode is made of glass

specially formulated to provide high

selectivity for Na .+The K +- sensitive

electrode consists of polyvinyl chloride

PVC impregnated with valinomycin, an

antibiotic that is selective for K .+The Cl--

sensitive

Samples can be diluted before analysis

“indirect method” or analyzed without

dilution “direct method.”

electrode consists of a liquid membrane

containing quaternary amines, which are

selective for chloride ions, in a PVC

support .A calcium ISE uses an ion

selective calcium sensor that consists of

either a neutral membrane PVC

impregnated with uncharged calcium

selective organic molecules dissolved in a

plasticizer or a negatively charged

membrane PVC impregnated with an

organophosphate.

Some errors observed when using ISEs

occur because of proteins coating the

membranes, lack of selectivity , or

contamination with ions that compete

with selected ion.

Calibration standardization has been

recommended to minimize deviations

among different ISE analyzers.

-Reagents

-Electrode Module

-Peristaltic Pump

-Sample Probe

-Waste Chamber

ELECTROLYTE ANALYZER

COMPONENTS

1 - Reagents

• Refers to the Cal and Slope standards

and the Wash solution.

• Cal and Slope solutions are two

calibration fluids of different

concentrations used during a Two Point

Calibration more on that later.

2 - Electrode Module

• Also referred to as a Flow Cell or

Electrode Train.

• Houses the:

- Air/fluid detector

-Measuring electrodes

- Reference electrode

• Wash solution may also be

referred to as a flush or rinse

solution and does just what it

implies, it cleans and rinses the

tubing after each analysis.

*Air Fluid Detector

• Located at the entrance or exit of the

Electrode Module.

• Verifies the presence of air or fluid in

the sample tubing.

– A small light source shines through the

tubing into a photodetector.

–The photodetector is monitored by the

μP which monitors the air/fluid detector

so it knows when to start and stop.

Reference Electrode

• Supplies a continuous electrical

potential that is used as a reference to

measure the electrical potential

produced by each ISE.

• Constant 756 mV potential

3-Peristaltic Pump

• Pushes the reagent fluids and

patient sample through the tubing to

the sample probe and Electrode

Module out to the waste bottle.

• Fluid is drawn into the analyzer as

the flexible tubing is pressed by the

rollers of the pump and drawn

through the tubing via the squeezing

action of the rollers on the tubing.

Flexible Rubber

Tubing

• Peristaltic Action

4-Sample Probe

• Aspirates fluids into the analyzer

via the peristaltic pump.

• The probe accepts fluids in the

STAT position up or Automatic

position down.

-Performed with the probe in the up position

- The probe accepts a handheld sample for a

single analysis.

- Performed with the probe in the

down position.

- The probe automatically accepts

samples from a test tube or a

cuvette in a tray or carousel.

-This is the position of the probe

during normal operation.

TWO POINT CALIBRATION

-A ‘Two Point Cal’ is a full calibration

usually run on a daily basis that

establishes the calibration and slope for

each electrode.

-Two standards of known analyte

concentrations are analyzed.

-Each electrode measures the analyte

concentration in both standards in order

to obtain the electrode’s slope

curve.

ONE POINT CALIBRATION

- Used to monitor and correct the

instrument for electrode drift.

• Electrode drift is a gradual change in

electrode potential that can adversely

affect electrode performance.

- Normally performed prior to every

analysis and involves just running the

cal standard through the instrument.

Very

important

The electrolyte analyzer must match

the facility’s present and future

testing requirements and

performance needs

Several performance features can

be used to assess accuracy and

reliability, including the following:

• Analytical range.

The concentration range over which an

instrument can measure a particular

Analyte.

Purchasers should check these values

carefully under conditions in their own

laboratories because actual ranges

may vary significantly from those

stated by the manufacturer

• Linearity. The linearity of an analyzer

determines how accurately the unit can

measure analyte concentration over a

certain concentration range as determined

against a given control or standard.

Instruments with large linear ranges can

analyze samples with awide range of

analyte concentrations without diluting or

manipulating them in any way. This feature

provides a faster turnaround of results and

may save operator time if dilutions must

be manually performed.

• Specificity. This is the ability of an

instrument to measure only the

analyte selected. In electrochemical

analyzers, this is a function of

electrode design and construction

• Precision .A high degree of

precision, which is a measure of

how closely a test result can be

reproduced, not only provides a

more sensitive determination

of changes in the patient’s

condition,

but also reduces the need for duplicate

testing to verify the accuracy of initial

test results .Precision is expressed

numerically in terms of the coefficient

of variation CV, with a small CV

indicating a highly precise instrument.

• Stability. Analyzers that give readings

with a high degree of precision for

extended periods of use have very stable

calibration curves. These units may be

less costly to operate than analyzers with

more labile curves because.

• Carryover .Residue left over on an ISE

from a previous sample is called

carryover .This results from incomplete

cleaning of the electrode with the wash

solution .Carryover can cause

erroneously higher or lower readings in

samples and result in unnecessary

duplicate testing.

they do not require recalibration

as often; the unit thus uses less buffer

and control and runs fewer non

patient analytical tests

• Downtime .Downtime occurs when

the analyzer is undergoing routine

maintenance or is shut down for

troubleshooting and repairs .A unit

that requires frequent maintenance

or has a poor reliability record cannot

consistently handle a normal

workload and will cost the laboratory

money to service (even with a good

service contract )and to compensate

for lost testing revenue .Under these

circumstances, a reliable backup

analyzer is a necessity.

Technical features

• Equipment Interface 4 line, 128 × 64 dots

LCD display with backlight and three keys.

• Analysis principle Direct “Flow Thru” Ion

selective electrodes (ISE).

. • Sample volume 100μl

• Sample type Whole Blood, Serum, Plasma,

Urine.

• Sample Application From Syringe, Sample

Cup, Capillary or Collection Tube.

• Throughput 60 samples/hour

without printout, 50 samples/hour

with printout.

• Calibration Automatic two-point

calibration with additional option for

carrying out one-point and two-point

calibration manually.

• Display 128 × 64 Dot LCD display with

backlight.

• Printer Built in Stationary Head

Graphical Thermal Printer.

• Normal Reference Range Users can adjust

reference range for all parameters according to

their requirements. Flagging of abnormal

samples provides easier analysis.

• Storage Capacity Patient Result: 250 samples.

• Interface port RS 232 Interface.

• Power Voltage: 165-250 V, 50 Hz; Power < 35VA.

• Dimensions 300(H) × 350(W) × 230(D) mm.

• Weight 6 Kg approx.

• Operating environment.

• Temperature 15° to 40°C.

• Relative humidity 20%~ 80%.