CEM SMART System 5 Operation Manual

600141

Rev.3

CEM

P.O. Box 200

Matthews, North Carolina 28106-0200

[phone] FAX: [phone]

e-mail: [e-mail]

Copyright 2000 by CEM Corporation

All Rights Reserved

This manual contains proprietary information which shall not

be reproduced or transferred to other documents or disclosed

to others without prior written permission

of CEM Corporation

SMART System5™ is a trademark of CEM Corporation

CEM is a registered trademark of CEM Corporation

U.S. patent 4,291,775; 4,438,500; 4,457,632;

4,554,132; and 4,753,889

Other U.S. and foreign patents pending

MANUFACTURED IN THE

UNITED STATES OF AMERICA

This instrument complies with United States Code of Federal Regulations (CFR) Title
21, Part 1030 for microwave leakage. A verification report is on file.

This instrument complies with United States Code of Federal Regulations (CFR) Title
47, Federal Communications Commission (FCC) Part 18 – Industrial, Scientific and
Medical (ISM) Equipment – emissions requirements. A verification report is on file.

i

NOTICE

The following precautions should be observed to avoid possible exposure to excessive
microwave energy:

• Do not tamper with the safety interlocks. The SMART System5 is equipped
with three safety interlocks which prevent the instrument from producing
microwave power if the cover is open.

• Do not place any object between the microwave cavity and the cover or allow
soil or cleaner residue to accumulate on sealing surfaces.

• Do not operate the instrument if it is damaged. It is particularly important that
the instrument cover close properly and that there is no damage to the cover
(bent), hinges and latch (broken or loosened), or sealing surfaces.

• The instrument should be adjusted or repaired only by qualified service
personnel.

The following precautions should be observed to avoid instrument-induced electromagnetic
interference:

• The possibility of instrument-induced electromagnetic interference (EMI) is
minimal if precautions outlined above are followed.

• The instrument should not be placed close to any electrical device susceptible
to EMI. It is suggested that the user post a sign warning pacemaker wearers
that a microwave device is in operation.

• If the instrument is suspected of inducing EMI, the cover should be carefully
inspected. A microwave leakage measurement should be performed as
outlined in the Troubleshooting, Maintenance and Service section of this
manual. Leakage measured above the legal limit of 5 mW/cm2 should be
reported to the CEM Service Department.

This instrument utilizes high voltages and microwave radiation.

Instrument service and
repair should be performed only by those trained in repair and maintenance of high
voltage and microwave power systems.

ii

To the best of our knowledge, the information contained herein is accurate. However,
CEM cannot accept liability of any kind for the accuracy or completeness of the
information contained in this manual. The final determination of the suitability and
proper use of the instrument described herein, the accuracy of the information and data
obtained from such use, and whether such use infringes any patents or the legal
safeguards of others are the sole responsibility of the user.

Warnings, Cautions and Notes

Warnings, cautions and notes are included throughout this manual and should be read
thoroughly and strictly followed.

WARNING: A warning is inserted for essential information used to emphasize
dangerous or hazardous conditions to the operation, cleaning and maintenance of the
instrument which may result in personal injury.

CAUTION: A caution is inserted for essential information used to emphasize
procedures which, if not strictly followed, may result in damage or destruction to the
instrument or improper instrument operation.

NOTE: A note is inserted for emphasis of procedures or conditions which may
otherwise be misinterpreted or overlooked and to clarify possible confusing situations.

iii

iv

Table of Contents

Introduction......................................................................................................1

System Installation...........................................................................................3

External Printer ..........................................................................................7

External Balance ........................................................................................7

Personal Computer or Serial Printer Setup ................................................8

Instrument Description ...............................................................................9

Sample Analysis ............................................................................................13

Sampling ..................................................................................................13

Preparation ...............................................................................................14

Weight ......................................................................................................16

Holders .....................................................................................................16

Application ...............................................................................................18

Method Information .................................................................................22

Bias Identification ....................................................................................23

Determining Ash/COH for Processed Meats ...........................................25

Ash Contents of Meats .............................................................................26

Methods Development .............................................................................29

System Operation

Quick Test ................................................................................................31

Constant Weight..................................................................................31

Set Time ..............................................................................................37

Edit/Create Method ..................................................................................43

Edit Method ........................................................................................45

Create Method.....................................................................................47

Moisture/Solids - Standard Test ....................................................47

Moisture/Solids - Wastewater - TSS .............................................53

Moisture/Solids - Wastewater - TSS/TVSS ..................................59

Moisture/Solids - Dilution .............................................................65

Moisture/Solids - Syringe Weigh - Internal Balance ...................73

Moisture/Solids - Syringe Weigh - External Balance ..................79

Moisture/Solids - Ash....................................................................87

Moisture/Fat or Moisture/Fat/Protein - Standard ..........................93

Moisture/Fat or Moisture/Fat/Protein - Dilutions .......................101

Moisture/Fat or Moisture/Fat/Protein - Modified .......................111

Load Method ..........................................................................................121

Setup.......................................................................................................123

System Options .................................................................................123

System Information...........................................................................125

Printer................................................................................................125

Communication Port .........................................................................126

Contrast .............................................................................................126

Clock .................................................................................................127

Calibration.........................................................................................128

Security .............................................................................................129

Company Name ................................................................................133

Delete Method...................................................................................134

Serial Options....................................................................................135

Unit Serial Number ...........................................................................136

v

vi

Table of Contents (Continued)

Print..............................................................................................................137

Statistics .......................................................................................................139

External Components...................................................................................141

Maintenance, Troubleshooting and Service.................................................143

Cleaning Recommendations...................................................................143

Routine Maintenance .............................................................................143

Special Tools and Kits ...........................................................................143

Troubleshooting .....................................................................................144

Error Messages .......................................................................................146

Standard Solution Test ...........................................................................147

Microwave Leakage Measurement ........................................................148

Intelli-Temp Calibration.........................................................................149

Intelli-Temp Verification .......................................................................151

Service and Repair .................................................................................153

Specifications .........................................................................................155

Warranty.................................................................................................156

1

Introduction

The CEM SMART System5™ Moisture/Solids Analyzer is designed to provide a
rapid moisture/solids analysis on a broad range of products. The patented weighing
technology provides continuous weighing of the sample during the drying process.
The system determines the precise time the sample is dry, and the moisture or
solids content of the sample is then automatically calculated based on weight loss.

Microwave energy is used to dry the samples. Polar compounds such as water,
polar organic solvents such as alcohols or ketones, and ions in the solution will
absorb microwave energy and volatilize. Once water and/or other solvents have
volatilized, the remaining solid material does not usually absorb microwave energy
and will remain relatively cool. Thus, the weight loss is due only to the volatile
solvents present in the sample. “Moisture” is used throughout this manual to refer
to any volatile substance for which the system can measure weight loss after
drying the sample.

The SMART System5 delivers 150 - 300 watts of microwave energy when

programmed for 100 percent power. Voltage of the incoming electrical service is
measured and the microwave power is adjusted by the power control system in
order to normalize the power and provide repeatable power conditions. Magnetron
power automatically adjusted to deliver appropriate wattage to the instrument cavity.
The magnetron fan remains on for 15 minutes after the end of the specified drying
time to cool the instrument.

System components consist of a microwave drying chamber, an electronic balance,
a 1/4” VGA black and white screen, an infrared temperature controller, a
microprocessor and an internal impact printer. The Octawave™ cavity is designed
to effectively deliver the microwave energy directly to the sample to achieve rapid
test times. The 50 gram four-place analytical balance has a ±0.1 mg sensitivity.
Infrared temperature measurement permits automatic adjustment of microwave
power based on user defined temperature setpoint. The microprocessor controls
and monitors system operations, automatically calculates sample results and
enables interface with external printers, external balances and/or computers.

The system is equipped with three safety interlock switches to monitor the mating
of the cavity cover and floor and one safety interlock switch to monitor the cavity
cover latch. A flame detector with an infrared feedback automatically turns off the
microwave power if excessive burning is detected.

The SMART System5 software is user friendly and easy to operate. It is capable of
storing up to 100 methods and 300 test results, and is multilingual (English,
German, Spanish, and French).

2

3

System Installation

1. Following the instructions provided in the packing carton, carefully remove
the SMART System5 from its shipping carton and place it on a vibration-free
workbench or laboratory table in a location that:

a. provides at least 8 in (20 cm) open space on each side and 6 in. (15 cm)

open space in the rear of the instrument for ventilation.

b. is free from vibration of large equipment and/or excessive walk-through

traffic.

c provides a temperature range of 41 °F (5 °C) to 104 °F (40 °C) and a

humidity range of 10-85 percent relative humidity.
d. provides adequate bench space for sample handling.
e. allows the instrument to be connected to a dedicated, grounded 120 or

240 VAC outlet. The SMART System5™ should be operated on a

stabilized, constant voltage AC power supply. To operate properly, the

voltage must be within ±10% of the specified level.

2. Retain all packing materials.

3. Inspect the instrument for cracks, dents or warping.

4. Remove the tape from the instrument cover. Inspect the top cover for proper
alignment. The cover must open and close freely with no binding or
restriction of movement.

WARNING

If damage is noted, do not attempt instrument operation.

AVERTISSEMENT

Ne pas mettre en marche si l’instrument est endommagé.

5. If the instrument has been damaged in shipping, contact the freight

carrier to report the damage and to file a damage report. Contact the
CEM Service Department or the nearest subsidiary or distributor (page 4)
to request service information.

6. Verify that all accessories illustrated and listed in figure 1 are included.

7. Lift the instrument cover. Install the balance stem into the balance stem
retainer in the opening of the cavity floor, ensuring that the balance stem is
firmly seated. Install the balance pan onto the stem.

Note: If the balance stem requires removal, lift the stem straight up from its
installed position. Moving the balance stem from side to side can cause damage to
the balance assembly.

4

CEM Corporation

Service Department

P.O. Box 200

3100 Smith Farm Road

Matthews, NC 28104 -5044 USA

Within the continental United States

Telephone: [phone]

Fax: [phone]

Outside the United States

Telephone: [phone]

Fax: [phone]

Subsidiary Offices

CEM Ltd.

2 Middle Slade

Buckingham Ind. Part

Buckingham MK18 1WA

United Kingdom

Tel: [phone]

Fax: [phone]

CEM GmbH

Carl-Friedrich-Gauss-Str. 9

47454 Kamp-Lintfort

Germany

Tel: [phone]

Fax: [phone]

CEM S.r.l.

Via Dell’Artigianato, 6/8

24055 Cologno al Serio

Italy

Tel: [phone]

Fax: [phone]

5

Figure 1. Accessories

• Starter Accessory Kit containing:

• Balance Stem (159600) (2)

• Balance Pan (004120) (2)

• Air Shield (568055M) (Installed in Instrument)

• Standard Solution (302600)

• Dispensing Bottle (230230)

• Spatula (302001)

• Disposable Pipette (302150)

• Glass Fiber Sample Pads (200150)

• 10 g Weight (260111)

• Fuses, 10AMP (2) (188340) and 5AMP (2) (188331)

• Operation Manual (600140)

• Printer Paper Holder (159065)

• Printer Ribbon (315122) (Installed in Instrument)

• Printer Paper (1 Roll) (315120)

Glass Fiber

Sample Pads

Reorder part # 200150

C

E

M

C

o

r

p

o

r

a

t

io

n

P

.

O

.

B

o

x

2

0

0

M

a

t

t

h

e

w

s

,

N

C

2

8

1

0

6

1

-

8

0

0

-

3

3

4

-

6

3

1

7

(

in

N

C

:

1

-

7

0

4

-

8

2

1

-

7

0

1

5

)

T

e

le

x

:

8

0

2

1

1

8

F

A

X

:

7

0

4

-

8

2

1

-

7

0

1

5

Moisture/Solids Analyzer

Operation Manual

6

8. Using a voltage meter, measure the voltage of the dedicated power outlet to
verify voltage (120 VAC, 60 Hz or 220/240 VAC, 50 Hz).

9. Facing the back of the instrument, use a small screwdriver to pry the dual
voltage supply from the power module.

10. Install the voltage slide switch in the proper direction for the measured
voltage (120V, 60Hz or 220/240V, 50Hz).

11. Based on the voltage selected in step 9, install the proper fuses in the dual
voltage supply – 10 AMP (60 Hz) or 5 AMP (50 Hz).

12. Install the dual voltage supply with the appropriate fuses and the properly
installed voltage slide switch in the power module.

13. If applicable, install the exhaust hose.

14. Plug the power cord into the power cord receptacle in the rear of the
instrument and into a grounded, dedicated electrical outlet. Note: If using
external components such as a printer, computer or balance, install these
components as outlined in this manual.

15. Position the power switch located in the rear of the instrument above the
power cord receptacle in the “on” position.

CAUTION

Permit the SMART System5™ to warm up (power switch on,
microwaves not being produced) for at least 45 minutes prior to
operation. If the instrument is switched off for an extended
period of time (weekend, holidays, etc.), ensure that warmup
time is permitted prior to use.

Mise en garde

Permettre une période de 45 minutes de réchauffement du
SMART System5 avant l’utilisation (interrupteur de courant en
marche, aucune micro-onde n’est émise). Lorsque l’instrument

est en mode fermé pour un temps prolongé (fin de semaine,
vacances, etc. . .) il est important que la période de
réchauffement de 45 minutes soit observée.

16. Refer to the “Maintenance, Troubleshooting And Service” section of this
manual and perform the Standard Solution Test at least five times.

Note: CEM Corporation recommends that the power cord be connected to an AC
power outlet and the power switch remain in the “on” position at all times. After
15 minutes of idle time, the SMART System5 assumes a “sleep” mode.

7

Instrument Description

Display – displays menu choices, instructional messages and analysis results on a
1/4 VGA black and white screen

Keyboard – controls operation of the SMART System5. Temperature, time, or
other numeric data may be entered with the numeric keys as requested on the
display.

Internal Printer – provides printout of methods, data and results.
Cavity – decreases test times due to its patented compact Octawave™ design.
Air Shield – prevents air flow within the microwave cavity from affecting weight

measurements.

Balance Pan – holds sample and sample pads during analysis.
Interlock Assembly – monitors mating of cavity cover and instrument skirt.

Display

Keyboard

Internal

Printer

Cavity

Air Shield

Balance

Pan

Figure 2. Smart System5 Front View

Interlock

Assembly

Interlock

Assembly

Interlock

Assembly

8

Enter – Press to store entered parameters and data in the computer memory.
Exit – Press to exit screen.
Ready – Press to initiate current method for a test or to reset method for next test.
Start/Pause – Press to begin or pause sample analysis. Microwave heating begins

when the Start/Pause button is pressed unless the cavity cover is open. Operation
will continue through the analysis unless the Start/Pause button is pressed to
interrupt the analysis or the operation key indicating “Stop Test” is pressed.

Tare – Press to tare or zero the weight of the sample pads prior to sample analysis.
0 - 9 – Press to select items from menus such as the Main Menu, setup screens, etc.

and to select values for parameters such as time and power.
▲ Operation Keys – Press to select specific operation options such as “Stop

Test,” “Print,” “Main Menu,” Prev. Page,” etc.

Figure 3. Smart System5 Keyboard

9

Fuses – prevent electrical power overload.
Power Cord Receptacle – receives the female end of the power cord.
Power Switch – turns electrical power to the instrument on and off.
Nameplate – lists model and serial number.
Dual Voltage Selector Switch - permits electrical voltage for the instrument to be

switched from 110 VAC to 220 VAC.
PC Port – permits connection and communication with a personal computer for

data storage, etc.

Printer Port – permits connection and communication with an external printer.
External Balance Port – permits connection and communication with an external

balance for specific applications.

Internal

Printer

Power

Switch

Power

Cord

Receptacle

Dual Voltage

Selector

Switch &

Fuses

Printer

Port

External

Balance

Port

PC

Port

Figure 4. Smart System5 Rear View

CE

CEM

Nameplate

10

11

Sample Analysis

Proper sample preparation and testing are critical to obtaining accuracy and
precision. Each sample has a specific characteristic composition; therefore, each
sample may require an individual method of analysis. However, guidelines can be
established for analysis of general sample types.

• Sampling – A representative sample is critical to obtain proper analysis.

• Preparation – As with any chemical analysis, a homogeneous sample is

critical to obtaining precision and accuracy.

• Weight – A consistent sample size helps ensure precision and accuracy.

Most CEM applications specify a sample size of 2-5 grams, emphasizing
the importance of a homogeneous sample.

• Holders – Absorbent pads to which a sample can be applied are used for

most analyses. Glass fiber pads are recommended because glass fibers do
not absorb microwaves. Other holders include Teflon coated glass fiber
mesh, a drying basket and a thermapad.

• Application – Most samples should be spread smoothly, avoiding lumps,

peaks or any uneven areas. Sample spread must be consistent.

• Drying Time – The drying time is determined by the type of sample and its

microwave absorbency. Constant weight drying permits drying of a sample
until a constant weight is achieved. Set time drying permits the control of
the sample analysis by entering a specified time and power level.

• Infrared Temperature – The infrared temperature measurement may be

used to operate at temperatures used in standard or vacuum oven
procedures.

• Microwave Power – The power necessary to dry a sample is determined by

sample composition. A sample should be tested at the highest possible
power without burning or degradation of the sample.

Sampling

Proper sampling of a product or process is critical in achieving proper moisture/
solids analysis. A representative sample is required to ensure that the test results
are representative of the entire batch or lot of material.

Many standard procedures such as AOAC, USDA and ASTM methods reference
sampling techniques. It is extremely important to follow techniques outlined in
these procedures for a particular sample type.

Proper handling and storage of the sample prior to analysis is also critical in
achieving accurate and representative results. Samples should not be exposed to
the air for long intervals prior to analysis. Proper storage also ensures that no
moisture is lost.

12

Preparation

Sample preparation is critical to achieving precise and accurate test results. The
sample should be properly prepared to achieve repeatable moisture results between
duplicate analyses of the same sample. Sample preparation is either a physical or
chemical modification of the sample. Physical modification may be as simple as
stirring or shaking the sample to ensure homogeneity or more complex such as
particle size reduction, dilution or deaeration.

Chemical modification is the addition of an enzyme to hydrolyze chemically
bound fat. The objective is to create a homogeneous sample and to improve the
correlation of the test method to standard methods. Some products, such as a beef
emulsion or comminuted poultry, may require no additional preparation. Other
materials will require particle size reduction, dilution or dearation prior to testing.
Samples should be kept cool and in sealed containers to prevent loss of moisture.
If repeatable results cannot be obtained on the same sample, re-blend the sample to
improve the homogeneity and repeat tests. Sample preparation methods include:

1. Mixing of Sample – Thoroughly stir or shake sample to ensure

homogeneity.

2. Particle Size Reduction – Many products require particle size reduction

prior to being applied to the glass fiber pad. Reduction, based on product
sample, can be accomplished with a meat grinder, either an industrial or
consumer grade food processor, a coffee mill or a cheese grater. The
meat grinder is the best choice for all meat products. USDA procedure
specifies three to four passes through a 1/8” or 5/64” blade with mixing
between grinds. A USDA inspector or outside laboratory can make
recommendations. An industrial grade food processor is a good
alternative for grinding meat products. A consumer grade food processor
is ideal for grinding frozen potatoes, breaded products, or “dry” snack
foods such as cookies, crackers, and chips. A coffee mill can be used to
grind or mix “dry” snack foods. A cheese grater can be used to grate
small quantities of hard cheese samples or soap.

3. Dilution – Products with a high carbohydrate content are strong

microwave absorbers and have a tendency to burn. These samples may
require either a water or salt dilution.

A. Water Dilution – A specified amount of sample is diluted with a

specified amount of water and mixed in a blender. Typical samples
include doughs, cheese powders, corn syrups, dried meat bases and
sauces. An external balance and a blender are required for this
procedure.

(1) Interface an external balance with the SMART System5.
(2) Tare the blender cup on the external balance.
(3) Add product sample to the blender cup.

13

(4) Add water to the product sample in the blender cup.
(5) Blend until a homogeneous mixture is obtained.
(6) Use the diluted sample to perform analysis.

B. Salt Dilution – A specified amount of salt is added to the product

sample prior to analysis. Typical samples include
frozen potatoes and frozen breaded products. This procedure
requires a teflon basket and dry table salt (sodium chloride).

(1) Line a teflon basket (CEM p.n. 200090) with two square glass

fiber pads.

(2) Place the lined basket on the balance of the Moisture/Solids

Analyzer. Press “Tare.”

(3) Place approximately 8g of salt in the lined basket. Press

“Tare.”

(4) Place the product sample on top of the salt. Press “Start” to

record the initial weight.
(5) Press “Stop.”
(6) Thoroughly mix the salt and sample in the basket.
(7) Return the basket to the balance of the Moisture/Solids

Analyzer. Press “Start” to continue the sample analysis.

4. Deaeration – Frozen dairy and imitation dairy products must be

deaerated to remove the excess air in order to provide reproducible test
results. This procedure requires a 125 mL Erlenmeyer flask, a 1 liter
beaker, a magnetic stirrer, a 11/2” x 3/8 magnetic stirring bar, and a #5
rubber stopper.

(A) Place 100 mL of sample in a 125 mL Erlenmeyer flask.
(B) Place a 11/2” x 3/8” magnetic stirring bar in the flask. Using a #5

rubber stopper, loosely cap the flask.

(C) Place flask in a 1 liter beaker containing 250 mL of water which has

been heated to 70°C.

(D) Place beaker with flask on a magnetic stirrer. Mix for 5 - 7 minutes.
(E) Cool sample to ambient temperature and thoroughly mix sample

prior to testing.

14

5. Enzymatic Hydrolysis – The fat in processed cheese and dairy products

is often tightly bound to the protein. In order to achieve accurate test
results, the fat must be released from the protein prior to the fat extraction
process. This can be accomplished by a protease enzymatic hydrolysis of
the sample. Note: The sample must be in a liquid or “pourable” state for
the enzymatic hydrolysis to be effective.

(A) Thoroughly mix approximately 100g of sample. Heat sample in a

water bath at 60°C (± 5°C) for five minutes.

(B) Add eight (8) drops of CEM Enzyme (p.n. 302630) and mix well.
(C) Return sample to water bath for five minutes.

Weight

Sample weight can be very critical to the final test result. As with most analytical
procedures, a consistent sample size helps ensure precision and accuracy. Sample
sizes can vary, based on type of sample, from 1 gram on the low end (high percent
solids level) to 10-15 grams on the high end (very low percent solids level). Test
procedures documented by CEM and included in this manual, are for specific
sample types and suggested sample size. Sample size should remain within the
weight guidelines. CEM has determined that the suggested sample size results in
the most consistent drying and test results. Heavier sample weights may cause
sample degradation or burning, resulting in high moisture results. Lower sample

weights may result in under-drying of the sample.

Holders

Sample holders should be transparent to microwave energy.
CEM Square Sample Pad – The square pad is the most commonly used sample

holder. Typically, two (2) pads are used with the sample “sandwiched” between
the pads. For heat sensitive samples, only one pad is recommended to minimize
heat buildup. For low solids samples, three or four pads are used for absorption.

CEM Round Sample Pad – The round pad is used as a collection pad for fat
extraction and is recommended, but not required, for thermapad applications.

Sample Pads – CEM glass fiber pads are designed to provide optimum
conditions for rapid, thorough and repeatable drying. CEM Corporation
follows strict specifications in the manufacture of sample pads. Specifications
include low moisture content and optimum absorbency, density, porosity, and
strength for microwave drying.

• Moisture Content – Excessive moisture in sample pads will cause

moisture or solids values to be incorrect. Controlling the moisture
ensures that residual moisture is maintained to very close
tolerances.

15

• Absorbency – The pad material must be absorbent enough to form a
wick for a liquid sample and to be a sample holder for more viscous
type samples.

• Density – The sample medium must have uniform density to guarantee
that the moisture will volatilize rapidly and evenly, without causing
residual heating.

• Porosity – Correct porosity of the pad material ensures maximum
surface area for liquid samples in order to increase
volatilization of moisture. Correct porosity helps prevent
sample degradation or burning.

• Strength – The tensile strength of the medium has a direct effect on the
ability of the sample pad to withstand the stress imposed during sample
application.

Teflon Coated Glass Fiber Mesh – The mesh is used as a holder for fiber
samples or as a “spacer” between multiple sheets of paper samples.

Drying Basket – The basket is made of Teflon coated glass fiber mesh. It is
typically lined with two square pads. It is used to hold large samples and for salt
dilutions.

16

Application

The viscosity of the sample plays an important role in determining how the sample
is spread onto the pad for analysis. If a sample is thin, it can be pipetted onto the
pad and can be tested at high power levels. A thin sample spread over a large area
permits moisture to evaporate rapidly with little residual heat buildup. Glass fiber
pads may be stacked for increased absorbency.

High viscosity samples (samples that do not flow well) require a different
technique. If the sample can be easily spread across the glass fiber pad, no dilution
is required. A thick sample will tend to puddle and form a crust, sometimes trap­ping volatiles within the bubble. Overheating or burning can also occur on thick
samples. If repeatable results cannot be obtained by spreading the sample, a
dilution may be necessary. The sample must be soluble in the diluting agent, and
the diluting agent must be a microwave absorber.

To generate the appropriate amount of heat and achieve optimum moisture results,
different types of samples must be spread to different thicknesses over different
areas of the glass fiber sample pad. As a general guideline, the sample will
generate heat in direct proportion to the thickness of the sample layer on the pad.
A sample spread too thickly can cause sample burning; a sample spread too thinly
can cause insufficient drying. The prepared sample should be applied to a glass
fiber sample pad. Once the sample is properly applied to the sample pad, it should
be covered with a second glass fiber pad to ensure heat retention and to eliminate
splattering.

Liquid samples should be pipetted onto the pad. Solids samples should be spread
onto a pad placed on the edge of a clean, flat surface, such as a countertop. The
spatula should be held level with the pad when spreading the sample to ensure a
smooth, uniform application of sample to the pad surface.

If the sample is an organic solvent-based liquid, special handling is required.
Equipment and method modification may be required. CEM recommends using
the SMART System5 Exhaust Kit when analyzing solvent based samples.

Non-polar organic solvents do not absorb microwave energy; therefore, samples
containing this type of solvent will not dry unless they are mixed with a diluent
which absorbs microwave energy and has a higher boiling point than the non-polar
solvent.

If the sample is a polar organic solvent-based liquid, samples will absorb
microwave energy and dry as readily as a water-based liquid. If the organic solvent
is an alcohol, a ketone, or an ester, samples should be tested with water-based
techniques.

17

Some base resins are microwave absorbers. Polyester is a known base resin that is
an absorber of microwaves. Titanium dioxide and calcium carbonate have also
been found to be microwave absorbent. If these materials are present in a sample,
usually enough heat is generated to remove most high boiling non-polar solvents
and any other volatiles. Oils become very hot when placed in the microwave field.
Some metal based samples can be tested. If carbon black is present in a sample, it
will heat very quickly and possibly burn even at low power levels.

It is recommended that CEM Corporation or a local distributor be consulted prior
to testing any solvent based sample.

General Sample Application Technique

If the sample is in a paste, semi-solid, or crumb form or a raw or skeletal meat
product such as fresh pork, ground beef, or chicken, place the sample on the end
of a spatula and spread it across one end of the pad. Then spread the sample to a
uniform thickness covering approximately 90% of the pad surface area.

1 Spread Thin Layer Across 90% of Pad

18

If the sample contains bound water such as an all-meat emulsion, cooked all-meat
sausage, sausage with extenders, semi-dry sausage, or ham, place the sample on
the end of the spatula and apply the sample to the middle of the pad. Then spread
the sample around the pad in a circle to generate thermal heat.

2 Spread Layer on Pad

If the sample is a heat sensitive sample such as a water-based or solvent-based
liquid, use a pipette to dispense the sample onto the pad(s). Sample size should be
2-5 grams, based on solid content of the sample – 2-3 grams for high solids
samples, 4-5 grams for samples containing less than 15 percent solids. Samples
containing less than two percent solids may require as much as 10 grams for
analysis. Large quantity samples should be pipetted onto the pads in a thin even
layer. Additional glass fiber pads may be used for increased absorbency. A
sufficient number of pads should be used to ensure that liquid samples do not drip
onto the floor of the instrument cavity.

3 Puddle, Spread with Pipette and Cover

19

4 Puddle and Cover

5 Swirl or Zig-Zag Pattern, No Cover

Standard application used for heat sensitive samples if sample burns when using

the puddle and spread technique.

If the sample is a water-based liquid or solvent-based chemical, use a pipette to
puddle the sample onto the pad(s). Cover the sample with an additional pad. A
sufficient number of pads should be used to ensure that liquid samples do not drip
onto the floor of the instrument cavity.

20

Method Information

Most water based samples should achieve constant weight settings in 1 - 3
minutes.

The microwave power and temperature settings should be appropriate to the
sample. The standard oven or vacuum oven temperature recommended in a
reference method for the sample should be followed. If no reference method is
available, a starting temperature of 100 °C should be programmed. Because the
power level in the instrument is adjusted based on temperature feedback, most
samples can be dried using a 100% power level setting. If a sample contains a
strong microwave absorber such as carbohydrates, the power level will likely need
to be adjusted. In most instances, a 10% power change will be sufficient to prevent
overheating.

During the initial testing of a new sample, the weight display should be monitored
to ensure that the sample does not ignite and that a stable weight reading is
displayed. Sharp declines in weight indicate excessive sample heating. If ignition
occurs, the flame detection sensor will abort the analysis.

Samples that are strong absorbers of microwave energy should be diluted or tested
at reduced power levels. These products usually contain simple carbohydrates or
tightly held moisture that will not readily escape, causing overheating and/or
burning and non-reproducible results. These samples should be tested at a low
power. Examples of heat sensitive samples include powders, paper fibers, candy
and black liquor.

21

Bias Identification

Most samples can be analyzed for percent moisture content with a CEM drying
method, and results will compare precisely with the standard test method.
Occasionally, however, all volatiles in a particular sample cannot be removed with
microwave power. Different spread techniques can be used to eliminate the need
for a moisture bias in most samples. Sometimes browning of the sample in the
same manner as in the air oven will also produce test results comparable to the
standard test.

If microwave moisture test results are repeatable, but not comparable to the
standard test results, a bias can be identified. With most samples, the bias will
amount to only a few tenths of a percent. To determine a moisture bias, prepare a
sample for testing, ensuring that the sample is homogeneous. Test this sample by
both a standard method and the CEM microwave method. Perform at least ten tests
by each method to check repeatability, then figure an average of the ten results.
Subtract the average of the microwave test results from the average of the standard
test results. Enter the resulting number (moisture bias) into the CEM moisture/
solids instrument. Corrected moisture test results will be displayed and printed. If
the difference in the average test results is a negative number, the power level
should be reduced and the tests should be repeated.

Some meat and poultry products, whether raw or cooked, show a fat bias when
analyzed with the CEM instruments. Less fat is extracted by a short solvent
extraction than by the longer ether extraction of the traditional Soxhlet technique.
The bias will be a constant for a given product and should be considered when
generating data.

Cooked sausage (i.e. wieners, bolognas, etc. with extenders) and other cooked
products tend to bind fat in the carbohydrate/protein structure of the cooked
product and will generally yield a lower fat value when extracted in the CEM
instrument than when extracted with the Soxhlet.

For proper determination and use of biases, results from the CEM instrument
should be compared with the results from traditional “long” or standard methods
used by USDA laboratories for compliance testing. Standard methods consist of an
air oven (four hours, 125°C) for moisture and Soxhlet (four hour ether extraction)
for fat. USDA recommends correlation of rapid fat and moisture methods with
these long methods.

USDA Processed Products Inspection Division encourages the use of rapid
methods for fat and moisture analysis to assist in better process control and
compliance. USDA recommends periodic back-up analysis (one in every 10 - 20
analyses) by standard long methods when rapid methods are used in approved
Total and Partial QC (TQC/PQC) Programs. Backup checks can be performed less
frequently as laboratories gain confidence in the established biases. CEM
Corporation also recommends a Quality Assurance Program for establishing and
maintaining biases and to ensure USDA compliance.

Prior to establishing a fat bias for the Fat Analysis System, a laboratory should be
confident of obtaining the best possible results for moisture, since precision of the
fat results will depend on the moisture results. Moisture results should have
repeatability between duplicate analyses of the same sample and a mean or

22

”average” moisture values that are close to the values being generated on the same
samples by standard oven. To obtain the best possible results for moisture, and
thus for fat, there are three factors to consider: 1) sample preparation, 2) sample
application technique and 3) power and time parameters.

After establishing moisture repeatability and achieving moisture results as close to
standard ”long” methods as possible, use the following procedure to identify fat
biases for different product categories.

1. Select three or more samples (approximately two pounds each) from
different lots of the same product.

2. Prepare each sample according to standard procedures (3 - 4 passes
through a 5/64” blade, with mixing between grinds, or equivalent).

3. Divide each ground sample in half and package and label sub-samples in
two separate, air-tight containers.

4. Analyze one set of the sub-samples (from step 3) in duplicate by standard
”long” methods – oven for moisture, Soxhlet for fat. If facilities and/or
personnel are not available for these tests, use an independent laboratory.
Request raw data (individual tests) from the laboratory, not the mean or
”average” value.

5. After obtaining the results from the standard ”long” methods, analyze the
other set of subsamples in the CEM Moisture/Solids Analyzer for
moisture only. Adjust power and spread technique until acceptable
moisture repeatability is achieved.

6. After obtaining acceptable moisture repeatability, use the Fat Analysis
System and perform 3 - 5 moisture and fat analyses for each sample. As
with moisture, fat results should be repeatable. To obtain optimum fat
results, use a sufficient redry time. Two minutes is typical, although some
samples may require more time. The sample weight should be stable
(<0.2 mg weight change in the last five seconds). An insufficient redry
time will yield artificially low fat results since the true dry, extracted
weight will not be reached.

7. Subtract values obtained from the SMART System 5 from Soxhlet values.
Average the differences to identify the average bias for a specific product
or product group.

Sample A B C

Average Soxhlet fat xx xx xx

- Average CEM fat xx xx xx
= Bias xx xx xx

(A + B + C)/3 = Average Fat Bias

8. The bias should be relatively less than 2.0% and must be added to the fat
results from the SMART System 5 to produce results that correlate closely
with official methods. Repeat this process on a regular basis to confirm
that the bias is consistent. Raw meats and blends will produce smaller
biases than cooked products with extenders.

23

Determining Ash/COH for Processed Meats

For samples that contain salt, sugar, spice, cure or other added components, ash/
carbohydrate (COH) values must be determined by analysis. For purposes of
calculating the protein by difference, the specific amount of each component (salt,
spice, bone, etc.) is not important, only the total amount.

To determine ash/COH values for finished products or blends with sugar, salt,
spice, etc., use the following procedure:

1. Collect and prepare three (3) samples from different lots of the same
product. Store the samples in airtight containers until tested.

2. Analyze the 3 samples in duplicate for fat and moisture in the
SMART System 5 and Fat Analysis System and for protein using “long”
methods (Kjeldahl). If necessary, an independent laboratory can provide
this analysis.

3. Average the results of the duplicate analyses for each sample, then total
the % Protein + % Fat + % Moisture for each sample.

4. Subtract the sum from 100% to get an Ash/Carbohydrate factor. For
example, if the composition of a sample is:

Moisture 52.54%
Fat 28.36%
Protein 11.25%
Total 92.15%

Ash/COH = 100% - 92.15%
Ash/COH = 7.85%

5. Calculate an average of the the ash/COH values for each of the 3
samples and program that factor into the SMART System 5.

Check samples periodically to verify the ash/COH values. Variations in the
amount of added constituents (salt, sugar, spice, extenders, etc.) can cause the ash/
COH factor to vary.

7.85%

11.25%

8.36%

52.54%

Moisture
Fat
Protein
Ash/COH