* • > * -

Fat determinationby solvent extractionwith Soxtec System

tecator

Sample prepa-ration(milling,homogenizationetc.)

weigh sample intothimble(Wi)

Dryingof samples

nnnnnHcm

Fix thimbles intoextraction unit

.

Fix weighed extrac-tion cups into Ex-traction Unit.

nnnonn 1Weigh extraction cups (W2) Add solvent to extraction cups

nnmnn

Boiling extraction withthimbles in submerged,boiling position (=^10 min)

- — iV™* *

Final extraction withthimbles in upper, rinsingposition (=^20 min) followed by sol-vent evaporation (=^5 min)

Remove extrac-tion cups

Dry extraction cups Weigh extraction fcups with extracted /o Ta i

fat(W3)

W3—W2 . i n n—wi—

>•£*„

L

L

Soxtec System

INTRODUCTION

UNPACKINGANDCHECKING

INSTALLATION 111:1 CONNECTION

FUNCTION IV:1 1040 EXTRACTION UNIT 8IV:2 1041 SERVICE UNIT 8IV:3 EXTRACTION CUPS AND CUP HOLDER 8IV:4 THIMBLE AND THIMBLE ADAPTERS 10IV:5 THIMBLE SUPPORT WITH HOLDER AND THIMBLE

STAND 10IV:6 THIMBLE HANDLER AND TONGS FOR EXTRACTION

CUPS 10

WTMWLM OPERATION

V:1V:2V:3V:4

V:5

PREPARATION OF SAMPLESTARTING UPEXTRACTIONSOLVENT RECOVERY, REMOVAL OF THIMBLESAND EXTRACTION CUPSSHUT DOWN

111111

1212

MAINTENANCEAND SERVICE Vl:1

Vl:2Vl:3Vl:4Vl:5Vl:6Vl:7

SERVICE UNIT 13WATER PUMP 13PRESSUREPUMP 13REPLACEMENT OF HEATING ELEMENT 13REPLACEMENT OF THERMOSTAT 15REPLACEMENT OF CONDENSERS 16REPLACEMENT OF SEALING MEMBRANE 16

Vl:8 REPLACEMENT OF RUBBER SLEEVE BETWEENCONDENSER AND EXTRACTION CUP 16

Vl:9. REPLACEMENT OF HOT PLATE 18VI:10 REPLACEMENT OF FLAT SPRING (HOT PLATE) 18Vl:11 ADJUSTMENT OF SPACE BETWEEN CONDENSER

AND HOT PLATE 18

TROUBLE-SHOOTING vil-1SCHEME Vll:2

FUNCTIONAL TROUBLE-SHOOTING SCHEMEMETHOD TROUBLE-SHOOTING SCHEME

1919

ELECTRICALDIAGRAM 20

ACCESSORIESAND SPAREPARTS 21

PROCEDURE ANDAPPLICATIONNOTES

MANUAL PART NO 1000-1540

INTRODUCTION

Crude fat is normally defined as what can be extracted by anappropriate organic solvent — such as diethyl ether. Traditio-nally, organic solvent fat extractions for quantitative fat de-terminations are carried out in Soxhlet or related extractors.Although time consuming and involving the handling of ex-plosive solvent these methods are universally used thanks togood accuracy and reproducibility.

The SOXTEC SYSTEM is designed to replace and improve thetraditional organic solvent methods. Still based on the tradi-tional Soxhlet procedure the patented design of the SOXTECSYSTEM makes it possible to carry out a quantitative deter-mination in only a fraction of the time needed for the traditio-nal procedures. In addition to the speed of the extraction,special attention has also been paid to make the SOXTECSYSTEM as safe as possible.

The SOXTEC SYSTEM has the flexibility to cope with manyorganic solvent extraction demands. This makes the SOXTECa convenient and versatile instrument whenever it comes toquantitative solvent extractions, e.g. in the food, feed andchemical/pharmaceutical industries as well as in researchand official laboratories.

The samples to be analysed are weighed into thimbles. Dur-ing the weighing the thimble is connected to the thimbleadapter and placed in the thimble support on the balance. Allhandling of the thimbles is done with the thimble handler. Norisk of fat contamination from fingers.

During the extraction in the Extraction Unit the fat is dissolvedin the solvent. After completion of extraction the solvent isevaporated from the extraction cup into the condenser. AMfat from the sample is now in the extraction cup.

The Service Unit provides hot water for heating up the hotplates in the Extraction Unit. The insulated tubing betweenthe Service and Extraction Units, makes it possible to placethe Service Unit in a separate room. This provides maximumsafety when working with diethyl ether. In the Service Unitthere is also a pump to give air flow into the extraction cupswhen evaporating the last residue of solvent.For specific method information please ask for applicationnotes.

UNPACKING AND CHECKING

Unpack the SOXTEC SYSTEM and its accessories with care.Remove all packing material. Use the packing list in this ma-nual or the one you find packed together with the unit, andcheck that you have received all parts. If any part is missing,contact your Tecator representative.

PACKING LIST

r

rPart no.

1040-001

1040-002

1040-003

1040-011

1041-011

Quant.

111

2111

3121

1331113113121

1

21121

Fig. pos.

A 123456789

10111212

A 13

1415161212

A:1 123

A:2 123

4

Description

Soxtec System M6 comprising:1040-011 Extraction Unit1041-011 Service Unit1000-1540 Manual

Soxtec System M12 comprising:1040-011 Extraction Unit1041-011 Service Unit1000-1461 AssemblyKit1000-1540 ManualSoxtec System M18 comprising:1040-011 Extraction Unit1041-011 Service Unit1000-1461 AssemblyKit1000-1540 Manual

Extraction Unit, complete, comprising:1040-012 Extraction Unit1000-1462 Extraction Cups (set of 6)1000-1431 CupHolder1000-1464 Thimble support (set of 7)1000-1080 Holder for thimble support1522-0018 Thimbles(setof25)1000-1466 Thimble Adapters (set of 6)1000-1467 Thimble Handler1529-0007 Tongs for extraction cups1000-1473 Thimble Stand1000-1476 Tubing (0 8/11 mm)1569-0010 Plastic strips1000-1469 Spare Part Kit A

Service Unit, complete, comprising:1041-012 Service Unit

(208—240 V, 50/60 Hz)1000-1432 Tubing for hot water1000-1477 Tubing for air1527-0019 Lubricatingoii1569-0009 Plastic strips1000-1468 Spare Part Kit B

Spare Part Kit A comprising:1000-1420 Sealing membranes (set of 6)1000-1424 Cylindricseals(setof 6)1569-0010 Plastic strips (set of 10)

Spare Part Kit B comprising:1577-0028 Shaft sealing (water pump)1577-0014 Membrane(pressurepump)1542-0026 Gasket (set of 4 for

hot water tubing)1569-0009 Plastic strips (set of 4)

Fig.A

Fig.A:1 Fig.A:2

INSTALLATION

Place the units on a laboratory bench. Depending on the sol-vent you are going to use, the Extraction Unit might be locat-ed in a fume cupboard separated from the Service Unit.

As an alternative there is a connection on the rear of the Ex-traction Unit which can be connected via fiexibie tubing to aventilation fan. The Extraction Unit must be placed close to acold water tap and drainage.

111:1. CONNECTIONConnect the PVC-tubing (0 8/11 mm) for cold water accordingtofig. B.Connect the insulated rubber tubing for hot water accordingto f ig. B. Make sure that the rubber seals are on place. (Fig. C)It is enough to fasten the connection by hand.

The Service Unit must be placed close to a wall socket. Neverconnect it without water in the tank. Connect the hot watertubing from the Extraction Unit and the PVC-tubing for air.Seefig. B.

If necessary the Extraction Unit can be placed further awayfrom the Service Unit (standard length of the hot water tubingis 3 m). For this purpose the 1000-1460 extension kit shouldbe used.

If you are going to connect an additional Extraction Unit usethe 1000-1461 assembly kit.

rr

Fig. B

1. Cold water inlet for con-densers (water flow 1—2 1/min.)

2. Water outlet from conden-sers

Hot water connections: 7 con-nected to 3 and 8 connectedto4Air tubing connection: 6 con-nected to 59. Electrical cable

1 2

6 o

708 O O9

3O

4O O

5o

Fig.C

Fig. D

When the Extraction Unit and Service Unit are connected, filldistilled (or deionized) water into the tank in the Service Unit(Fig. D). As soon as the element in the tank is covered withwater (ca 2 I), plug into the wall socket (208/240 V, 50/60 Hz, 10A) and switch on "MAINS". Open the valve "HEATING" onthe Extraction Unit to get rid of air in the hotplates and tub-ing. Fill more water into the tank. The water level should be afew cm below the edge of the tank. (ca 4 I with one ExtractionUnit and Standard tubings).

Fill about 50 ml of the lubricant oil (1527-0019) into the tank(this is in order to avoid unnecessary wear of the pump).

The thermostat is adjusted to about 90°C when the equip-ment is shipped to you. If you want a lower temperature, usea small screw driver and turn the screw on the thermostatcounter clock-wise. Fig. E. (Check temperature with a thermo-meter in the tank.)

Normal heating-up time from room temperature to 90°C isabout 15 minutes (220 V). Switch on "AIR" to check that theair pump is working.

NOTE: Always run a blank with the new equipment to get ridof deposits in the condensers.

Fig. E

FUNCTION rThe SOXTEC SYSTEM com-prises:— 1040 Extraction Unit— 1041 Service Unit— Extraction Cups— Cup Holders— Tongsfor extraction cups— Thimble Supports— Hoider for thimble sup-

ports— Thimbles— Thimble Adapters— Thimble Handler— Thimble Stands— Tubing for hot water and

air

IV:1. 1040 EXTRACTION UNIT (Fig. F)

In the Extraction Unit the fat extraction is done in two steps.First the thimble with sample is immersed in the boiling sol-vent. Most of the fat now dissolves in the solvent. In the sec-ond stage the thimble is raised above the solvent surface andthe fat residue in the sample is washed out by the solventdropping from the condenser.

After the extraction the knob above the condenser is turnedclockwise. This will close the outlet for condensing solvent.After some minutes most of the solvent is collected in thecondenser. The last residue of solvent is evaporated whenthe air valve is opened.

IV:2. 1041 SERVICE UNIT

The Service Unit provides hot water to the Extraction Unitfrom a built in tank. The thermostat in the tank is adjustablefrom the outside of the Service Unit (Fig. E). The hot water ispumped from the Service Unit to the hot plates in the Extrac-tion Unit. The pump can work even if the valve on the Extrac-tion Unit isclosed.

In the Service Unit there is also a pump to give the air flow forevaporating the solvent.

IV:3. EXTRACTION CUPS AND CUP HOLDER

With the cup hoider all six extraction cups are carried withone hand when inserting and removing them in the Extrac-tion Unit, or when moving them to the balance. The extractioncups are made of aluminium. Never place the extraction cupson a dirty surface during analysis. This might alter the tareweight. Before use check that the bottom surface of the cupsis clean, otherwise the heat transfer from the hot platosmight be disturbed and result in longer boiling start time.

8

Explanation of symbols in fi-gure F1. Recoveryknob2. Condenser3. Extraction mode knob4. Sliderail5. Extraction Cup6. Cup Hoider7. Hotplate8. Air valve9. Hot water valve

10. Fastening mechanism11. Lever for fastening

mechanism

IV:4. THIMBLE AND THIMBLE ADAPTERS

Standard size of thimbles is 0 26 mm and length 60 mm.Thimble adapters for other thimbles are also available (0 22mm, length 50 mm; part no: 1000-1486).

IV:5. THIMBLE SUPPORT WITH HOLDER AND THIMBLESTAND

Six thimble supports are fastened in the holder. (Fig. G) Thiscombination is used to fix the thimbles (in thimble adapters)to the magnets in the condensers of the Extraction Unit. Onethimble support is used on the balance when weighingsample into the thimble.

The thimbles are placed in the thimble stand during drying.

IV:6. THIMBLE HANDLER AND TONGS FOR EXTRACTIONCUPS

To avoid finger prints on thimbles, the thimble handler isused when moving a thimble from the balance to the thimblestand or the thimble support. (Fig. H) For the same reason thepair of tongs is used when placing extraction cups in a dryingoven oradesiccator.

rFig.G

fIL

Fig. H

10

OPERATION

V:1. PREPARATION OF SAMPLE

Samples must be ground or homogenized before weighed in-to the thimbles. Some types of samples e.g. meat, should bemixed with sand or asbestos. Follow the same procedure asfor traditional Soxhlet.

's.

Fig. I

m

fiSSüï

Fig.J

V:2. STARTING UP

A) Check water level in the Service Unit (should be a few cmsbelow the edge of the tank).

b) Press MAINS button (switch-lamp should light).

c) Open the left valve on the Extraction Unit to HEATING.This will allow the water to circulate. Normal heating-uptime (to 90°C) is about 15 minutes.

d) Open cold water tap for the reflux condensers. The flowrate should be adjusted to 1—2 l/min to prevent loss ofsolvent from the tops of the condensers.

V:3. EXTRACTION

a) Attach thimble to adapter (Fig. I).

b) Weigh sample into thimble (the thimble is placed in thesupport on the balance).

c) Move thimble to the thimble stand. Use thimble handler.The thimble is released when the handler is pressed. Dry inoven.

d) After drying, put defatted cotton plug above the sampleand place thimbles in thimble support (in holder). Usethimble handler. (Fig. J).

e) Insert the thimbles into the condensers. Raise the holderso that the support enters into the condensers. Note, thesix knobs (extraction mode) should be in the rinsing posi-tion (Fig. K).

f) Move each extraction mode knob up to boiling position.The magnet will now fasten the thimble adapter. Returnthe knob to rinsing position, the thimble will now hangjust under the membrane in the condenser.

g) Take out the thimble supports.h) Insert six extraction cups, tared with boiling chips and

loaded with about 50 ml of the solvent to be used (see pa-ra V.4.g). Use the cup holder. Lower the handle ensuringthat the safety latch engages. The cups are now tighte-ned to the condensers (Fig. L).

i) Move the extraction mode knobs to "boiling". The thimb-les will now be immersed in the solvent.

j) Open the valve "HEATING" and boil with the thimbles im-mersed. (Time depending on sample and solvent type.)Make sure that the knobs above the condensers are in up-

11

per position (full counter clock-wise) so that the conden-sing solvent can reflux back into the cups (Fig. M).

k) Move the extraction mode knobs to RINSING. The thimb-les will now hang above the solvent surf ace and any fatresidues will be rinsed out.

f

V:4. SOLVENT RECOVERY, REMOVAL OF THIMBLES ANDEXTRACTION CUPS

a) After the rinsing period turn the knob above the conden-ser clock-wise until the tube enters a few mm through themembrane. The tube will tighten and prevent the conden-sing solvent flowing back into the extraction cup.NOTE: If the tube is moved too f ar down it will stick to themembrane when all the solvent is evaporated.

b) When almost all solvent is collected in the condenser(about 4—5 minutes for 50 ml diethylether), Press AIR but-ton on the Service Unit and open the valve EVAPORATIONon the Extraction Unit. The last residues of solvent willnow be collected in the condensers.NOTE: If the Service Unit is located in another room theAIR pump can be on all day.If the EVAPORATION air flow is used earlier the time forevaporating the solvent will be shorter but some solventwill be lost.

c) Close the HEATING and EVAPORATION valves. Releasethe extraction cups with the safety hook (Fig. N). Lift outall six cups with the cup holder.

d) Place thimble supports (in holder) onto the hot plates andlower the handle so the supports enter the condensers.

e) Move extraction mode knobs so that the thimbles enterthe supports.

f) Release handle, follow the upward movement with thesupport holder. Bend the support holder (Fig. O) and re-move the thimbles.

g) If another extraction is to be performed immediately, in-sert a new batch of thimbles and cups (para V.3, e—h)and open the recovery valves by tuming the knobs abovethe condensers counter clockwise.NOTE: If diethylether is used make it a rule to empty therecovered solvent into a cup and check for peroxides be-fore reusirfg.NOTE: If recovered volume is too small, add more solventwith a syringe in the small hole in the white ring on thetop of the condenser (50 ml leve! is just below lower edgeof front panel) (Fig. P).

V:5. SHUTDOWNa) Turn off M Al NS.b) Turn off cold water tap.c) Check that all condensers are emptied of solvent. Leave

the knobs above the condensers in upper position (coun-ter clock-wise).

r

iFig. M

Fig.N

12

MAINTENANCE AND SERVICE

Vl:1. SERVICE UNIT (general for all work inside the ServiceUnit)

a) Take out electrical plug from wall socket.b) Unscrew the four screws (two on each long side) and lift

up the cover (Fig. Q and R, pos. 2).

Vl:2. WATER PUMP

If the pump leaks, the O-ring and shaft seal can be replacedasfollows:a) Empty the watertank.b) Loosen the screws on the two tubing clamps. (Fig. R, pos.

1)-c) Unscrew the nuts holding the pump motor. (Fig. R, pos. 3).d) Take avvay the pump.e) Loosen the eight screws holding the pump housing. (Fig.

R, pos. 18).f) Remove front part of the pump housing. (Fig. S, pos. 1).g) Remove the old O-ring. (Fig. S, pos. 2).h) Remove the pump rotor (Fig. S, pos. 3) by loosening the

centre screw (note screw clock-wise) (Fig. S, pos. 4).i) Loosen the four screws holding the rear part of the pump

housing and remove it (Fig. S, pos. 5).j) Unscrew the three screws holding the shaft seal and re-

place the seal (Fig. S, pos. 6, 7).k) Assemble the pump housing with a new O-ring.

Fig.Q

Vl:3. PRESSURE PUMP

1) To increase the air flow screw clock-wise on the plasticscrew on the side of the air pump (Fig. R, pos. 8).

2) Replacement of membrane:a) Unscrew the nut holding the pump and lift it out.b) Unscrew the screw for membrane (Fig. R, pos. 10).c) Remove the rubber base of the pump and change mem-

brane (Fig. R, pos. 9).d) Replace the base and f ix the pump into the unit.

Vl:4. REPLACEMENT OF HEATING ELEMENT

a) Empty the water tank.b) Unscrew the nut holding the tank (Fig. R, pos. 11).c) Loosen the screws on the two tubing clamps on the tank

(Fig. R, pos. 12).d) Loosen the nut on the thermostat body (Fig. R, pos. 13).e) Lift out the tank, carefully remove the thermostat body

from the tank.

13

14

Explanation of symbols inFig.R1. Tubing clampscrews2. Screws for cover3. Nuts holding motor4. Capacitor5. Thermostat6. Thermostat body7. Air pump8. Plastic screw for adjust-

ting of airflow9. Air pump membrane

10. Screw to be unscrewedbefore changing mem-brane

11. Nut holding watertank12. Screws to be loosened

before removing watertank

13. Nut for thermostat body14. Nutfor heating element15. Heating element16. Cableconnection on

thermostat17. Nut for thermostat18. Screw holding water

pump housing19. Watertank

f) Remove the cable connections.g) Remove the nuts holding the element (Fig. R, pos. 14).h) Replace the element (Fig. R, pos. 15). Make sure that the

sealings are inside the tank.

Vl:5. REPLACEMENT OF THERMOSTAT

a) Follow the procedure Vl:4, a—e.

b)

c)d)

Disconnect the two cables on the thermostat. (Fig. R, pos.16).Remove the nut on the thermostat. (Fig. R, pos. 17).Replace the thermostat and reassemble the Service Unit.

Fig.S

2.3.4.

5.

6.

7.

Explanation of symbols

1. Front part of pump hou-singO-ringPump rotorCentre screw to pump ro-torScrew holding rear part ofpump housingScrew holding the shaftsealShaft seal

15

Vl:6. REPLACEMENT OF CONDENSER (complete)

a) Raise all extraction mode knobs to middle position in theorange area.

b) Unscrew the three screws holding the front panel andgently pull the panel down. The six slides will come outfrom their plastic rails (Fig. T, pos. 1).

c) Remove the two nuts from the top plate (Fig. T, pos. 2).d) Lift away the top plate.e) Carefully loosen the glass condenser and pull it up until

it is clear of the seal (the condenser is pressed down intothe rubber sleeve).

f) Disconnect the PVC-tubing.g) Replace the condenser (Wet the glass before putting it in-

to the rubber sleeve).h) Assemble and run a blank to get rid of deposits.

Vl:7. REPLACEMENT OF SEALING MEMBRANE

a) Follow the procedure for replacement of condenser (Vl:6,a—d).

b) Lift away the knob on the recovery tube. The tube must bein its upper position (Fig. U, pos. 1).

c) Lift away the upper condenser holder and ease it over thecurved tube.

d) Carefully loosen the condenser (see Vl:6 e). Let the con-denser hang on its PVC-tubings.

e) Slide the flexible wire into the curved tube so that themagnet is free below the condenser (Fig. U, pos. 3,5).

f) Pull out the magnet with rod and flexible wire.g) Lift up recovery tube through the condenser (Fig. U, pos.

4).h) Take out the old membrane. To eliminate the risk of break-

ing the glass condenser, the best way is to cut the mem-brane with a knife or a scalpel.

i) Put in the new membrane. Wet it with water first. Press itin as far as possible using fingers. For the last part use aspatula. The membrane must fit into the groove in thecondenser.

j) Assemble the condenser and put it back in its place. Runa blank to get rid of deposits.

Vl:8. REPLACEMENT OF RUBBER SLEEVE BETWEEN CON-DENSER AND EXTRACTION CUP

r

a)

b)c)d)

16

Loosen the condenser. Follow the procedure for replace-ment of condenser (Vl:6, a—e). Let the condenser hang inthePVCtubings(Fig.V).Pull down the old sleeve.Withdraw the teflon tubing.Ease off the guide ring from the rubber sleeve and put iton the new sleeve. Make sure the hole in the ring fits overthe hole in the rubber sleeve (Fig. W).

r

Explanations to symbols inFig.T1. Screws holding the front

panel.2. Nuts holding top plate.

Fig.T

S B B P ^ '•"

Explanation of symbols

Knob on recovery rodUpper condenser holderFlexiblewireRecovery tubeCurved tubeMagnetwith holdingmechanismSealing membranePlastic rail forslideSlideExtraction mode Knob.

L_ 17

e) Put the teflon tubing into the hole, so it enters about 1 mminside the rubber sleeve. It might be necessary to use apin to clear the hole in the rubber part.

f) Put the new sleeve on place and replace the condenser.Run a blank to get rid of deposits.

Vl:9. REPLACEMENT OF HOT PLATE (Fig. X)

If distilled or deionized water is used in the Service Unit therewill be no problems with the hotplates. If for some reason tapwater is used, deposits inside the hot plate can disturb orclose the water f low.

r

Fig.X

Fig.X1. Hot plate2. Snap ring

a) Empty the water tank and disconnect the hot water tubing Explanation to symbols infrom the Extraction Unit.

b) Turn the apparatus so it is resting on the rear plate.c) Remove the tubing from the hotplate.d) Remove the snap ring. (Spring loaded).e) Lift up the hot plate.f) Put in the new hot plate. Make sure that the flat spring is

in place. Replace the snap ring and connect the tubingagain.

VI:10. REPLACEMENT OF FLAT SPRING (HOT PLATE)

a) Remove the hot plate (according to Vl:9, a—e).b) Replace the flat spring.

Vl:11. ADJUSTMENT OF SPACE BETWEEN CONDENSERAND HOT PLATE

Inside the lower part of the unit there are two adjustingscrews (Fig. Y, pos. 1). Loosen the nuts and adjust the spaceso that the extraction cups are firmly fixed.Fig.Y

Explanation of symbols inFig.Y1. Adjusting screws

18

TROUBLE-SHOOTING SCHEME

Vll:1. FUNCTIONALTROUBLESHOOTING SCHEMEFaultA. The waterpump does not

startB. The hotplates do not

heat up

C. Poor reflux of solvent

D. Solvent leakes out

F. Hotwater leakage

Probable Cause1. Nocurrentto the pump

1. Too low temperature intank

2.1.

2.

3.

4.

1.

2.

E. Too long evaporation time 1.

2.

3.

4.

1.

2.

3.

Heating valveclosedToo low water flow in thecondensersToo low temperature onthe hotplatesExtraction Cup contamina-ted on bottom surfaceRecovery Valve closed

Extraction Cup incorrectlyplacedRubber Sleeve betweencondenserand extractioncup isdamagedToo low temperature onthe hotplatesExtraction Cup contami-nated on bottom surfacePoor ornoairf low

Sealing membrane dama-gedUnsatisfactory tighteningof theconnectionsRubber seal in the connec-tion isdamagedShaft seal on the waterpump isdamaged

Corrective Measure

Connect the cable. Switch onMainsScrew the thermostat clockwise(Check temperature with a ther-mometer in the tank)Open the Heating valveIncrease the water flow

Adjust thermostat in watertank

Clean the Extraction Cup

Open Recovery Valve. Turncounter clockwisePlace Cups on center of the hotplatesReplace the rubber sleeve

Adjust thermostate in water-tankClean the Extraction Cup

Check that evaporation valve isopen and that the PVC-tubingbetween Service and ExtractionUnit is not blocked. Check thepressure pump according topara Vl:3Replace membrane accordingtopara Vl:7Fasten the connections

Replace the seal

Replace the shaft seal accord-ing topara Vl:2

Vll:2. METHOD TROUBLE SHOOTING SCHEMEFaultA. Too great deviation bet-

ween results from tests onthe same sample

B. Solvent (with fat) frothingup on the thimble duringrinsing or evaporation

Probable Cause1. Too coarse structure of

the sample

2. Unsatisfactory mixing ofsample prior to weighing

3. Unsatisfactory weighing inof sample or cups

4. Too short extraction time5. Poor reflux1. Too high fat content2. Too high temperatureon the hot plate

Corrective MeasureGrind or homogenize to a finerstructure

Check the mixing procedure

Check the weighing procedure

Check the extraction timeSee section C under Vll:1Weigh in less sampleAdjust the thermostat in thewatertank

19

ELECTRICAL DIAGRAMr

1041 Service Unitr

200—240V

MAINSWITCH

AIRSWITCH

THERMOSTAT

AIRPUMP

WATERPUMP

HEATINGELEMENT

20

ACCESSORIES AND SPARE PARTS

IX:1. ACCESSORIES(for one piece) Order no

Extraction cups (set of 6) 1000-1462Cup Holder 1000-1431Tongs for extraction cups 1529-0007Thimbles0 26mm(setof25) 1522-0018Thimbles0 22mm(setof25) 1522-0009Thimble support (set of 7) 1000-1464Thimble adapters (set of 6, 0 26 mm) 1000-1466Thimble adapters (set of 6, 0 22 mm) 1000-1486Holder for thimble support 1000-1080Thimble Handler 1000-1467Extension kit for distribution of hot water and air,

comprimising: 1000-14602 ea tubing for distribution of hot water (L = 3 m)

complete with connections1 ea tubing for distribution of air (L = 3 m

0 4/6 mm) complete with connectionsAssembly kit for additional Extraction unit,

comprising: 1000-14612 ea Tubing for distribution of hot water

(L = 0.75m)inclT-piececonnection1 ea Tubing for distribution of air

(L = 1 m, 0 4/6 mm)Lubricating oil (for Service Unit) 1527-0019

L-,

L

IX:2. SPARE PARTS

For extraction Unit:Condenser, complete, with recovery and

thimble mechanism 1000-1445Condenser, glass 1000-1419Sealing membrane in condenser 1000-1420Knob for recovery rod 1000-1423Cylindric seal between condenserand extrac-

tion cup 1000-1424Valve for hot water and air 1584-0006Tubing for cold water, 0 8/11 mm, per m 1582-0004Tubing for hot water, 0 6/12 mm, per m 1582-0023Tubing for air, 0 4/6 mm, perm 1582-0005Hot plate, complete 1000-1444Flat spring for hot plate 1000-1404Strips, big 1569-0010Timer 1562-0017

For Service Unit:Water Pump, complete 1577-0024Shaft sealing to water pump 1577-0028O-ring to water pump 1577-0027

p.t.o.

21

Air pump 1577-0008Air pump membrane 1577-0014Heating element 1000-1403Thermostat 1579-0007Strips, smal I 1569-0009Switch red 1563-0001Switch yellow 1563-0006Pump body to water pump 1577-0029

tecator

J

1980.01.15 RA/ML AN 23/80

RAPID DETERMINATION OF CRUDE FATIN FEED STUFFS

BY USING THE SOXTEC SYSTEM

(DIETHYLETHER)

I. INTRODUCTION

The classical Soxhlet extraction with diethylether has for a long time been

used for the determination of crude fat in feed stuffs. Bowever, the method

is tedious and labour intensive. The SOXTEC SYSTEM has been developed to

eliminate the drawbacks of the original procedure. A number of determinations

have been perforraed to evaluate the SOXTEC systera in comparison with the

classical Soxhlet method.

As most fats and waxes are more soluble in hot solvents than in cold ones,

the sample in the SOXTEC EXTRACTION UNIT is first submerged in the boiling

solvent after which the remaining fat is rinsed out by the refluxing solvent

with the sample raised above the solvent surface.

This application note describes crude fat determination on f eed stuffs and

raw materials using diethylether as solvent.

II. MATERIALS

The test samples used in this study included pig feed (3), cattle feed (3),

poultry feed (2), coconut oil meal (1), cotton seed meal (1), oats (1),

fish meal (1) and corn (1). The moisture content of the samples was in the

range of 8 - 12 per cent and the samples were ground on a Cemotec mill set

to pos. 1.

III. EQÜIPMENT

1. Cemotec Mill (1090 - 001) or a Cyclotec sample mill (1900 - 0300).

It should be kept in mind that the Cyclotec mill will dry the samples

to some extent and that the results must be adjusted accordingly.

2. Analytical balance with an accuracy - 0.1 mg.

3. Soxtec System M6 (1040 - 001) complete with accessories.

4. Thimbles 26 x 60 mm (1522 - 0018).

5. Graduated cylinder 50 ml.

6. Heating oven (95 - 100°C).

7. Desiccator.

IV. CHEMICALS

1. Diethylether (anhydrous) f ree from solids, and peroxides. Store in

dark place over metallic sodium. Check regularly for peroxides.

Procedure for peroxide test: 2 - 3 ml diethylether is shaken with

1 ml of a dichromate solution (1 % K,Cr9O7 in 0.1 N sulphuric acid).

If it turns blue the ether contains peroxides and should be discarded.

1980.01.15 RA/ML AN 23/80

C A U T I O N

DIETHYLETHER IS HIGHLY INFLAMMABLE AND SHOULD ONLY BE USED BY QUALIFIED

LABORATORY TECHNICIANS WHO HAVE BEEN PROPERLY TRAINED IN THE SAFETY ASPECTS

OF ITS USE. PIACE THE SERVICE UNIT IN A SUITABLE PLACE WELL APART FRCM THE

PLACE WHERE DIETHYLETHER IS HANDLED. MAKE SURE THAT VENTILATION IS ADEQUATE

AND THAT THE SOLVENT IS FREE FROM PEROXIDES.

2. Cotton wool (defatted).

3. Boiling chips (glass balls 0 •* 3 mm).

V. PROCEDURE

1. Turn on the Service unit in order to heat water to the working

temperature (75 C).

2. Fix thimble into thimble adaptor and place it in the thimble

stand. Put sorae cotton wool in the bottorn of the thimble. Always

use defatted thimbles and cotton wool. Never handje them with

your bare hands.

3. Place a thimble support on the balance. Use the thimble handler

to transfer thimble (fixed to adaptor) from the stand to the

support. Tare support plus thimble and weigh in the ground and

well mixed sample. Note the weight (W1) .

Use about 3 g if fat content < 10 %

use about 2 g if fat content > 10 %.

Put a plug of cotton wool on top of the sample.

4. Dry the thimbles with sample in an oven (95 - 100 C)

for two hours.

1980.01.15 RA/ML AN 23/80

5. Weigh clean and predried extraction cups with some boiling chips (W2).

Never touch the clean extraction cups with bare hands!

6. Transfer the dried thimbles with the thimble handler into the thimble

supports (6 pcs fixed to its holder).

7. Insert all six thimbles into the Extraction Unit and make sure they are

all properly held by the magnets. Place all thimbles in the "rinsing"

position and then remove the holder with the supports.

8. Put about 50 ml diethylether into the preweighed extraction cups

(6 pcs placed in a cup holder) .

9. Insert the extraction cups with the holder into the Extract ion Unit.

Make sure they are placed in the centre of the hot plates and lock them

in place by lowering the handle on the left of the Extraction Unit.

The cups will then tighten against the seals on the condensers.

10. First switch on cold water through the condensers and then switch on

the "heating" valve. Preheated water (^75 C) from the Service Unit

will then flow through the hot plates and heat the solvent to the

boiling point.

11. Move the thimbles to the "boiling" position and make sure that there

is good reflux from the condensers. Turn the recovery knob to f uil,

counter clock wise (upper) position.

12. After 10 or 15 minutes boiling, raise the thimbles above the ether

surf ace by moving the knobs on the panel to the "rinsing" position.

13. When the rinsing period is over turn the recovery knob clockwise

(until the tube enters a few mm through the membrane) and collect

the solvent in the "condenser trap".

1980.01.15 RA/ML AN 23/80

14. After the solvent has been col lected for 2 - 3 minutes move the ...

a i r valve to t he "evaporation" posi t ion and co l lec t the l a s t residue of

the solvent in t h e condenser t r a p . (Make sure tha t the a i r pump in the

Service Unit is switched on.)

15. Release the ex t rac t ion cups by r a i s ing the handle on the l e f t of the

uni t and remove the cups from the Extraction Unit using the cup holder

and place them in the oven (95 - 100°C)for 30 minutes .

16. Gooi the cups in a desiccator.Weigh them (WJ and calculate percentage

of fat according to formula:

W - W% crude f a t = - ^ - — x 100

w1

17. After analysis r i n se extract ion cups wi th ' su i t ab le solvent

and wipe dry with soft paper. Empty thimbles for reuse.

VI. RESULTS AND COMMENTS

The 13 samples were analysed using two different times for the

'boiling extraction" and "rinsing" periods respectively. As can

be seen in table 1 the shorter period was in most cases sufficient

to achieve reliable results. However, there is a slight tendency

to higher values on some of the samples after the longer extraction

period. Also the relative error was found to be slightly lower

(- 1.36 %) for the longer extraction period (45 min.) than for

.the shorter one (- 1.52 %) . Accordingly the 45 minutes extraction

period should be chosen for this type of samples if maximum relia-

bili ty is the ultimate goal.

As can be seen in table 2 the results achieved on the SOXTEC

system agreed quite well with the results from the three

laboratories using classical Soxhlet equipment and 18 hours dura-

tion of extraction in the same solvent. The differences between

1980.01.15 RA/ML AN 23/80

the three Soxhlet laboratories, of which two (A and C) are official

laboratories and the third (B) is a well reputed large laboratory in a

fcooperative organization, emphasxze the difficulties in gettxng comparable

xesults using the Soxhlet method. There is no doubt, hpwever, that there is

a remarkable good correlation between all the laboratories involved in the

tests. If laboratory A, one of the official laboratories, is used as a

reference, correlation coefficients and confidence intervals can be

calculated according to table 3.

In some recent studies it has been demonstrated that the par t ic le

size does have a significant effect on the extractabil i ty of the

fat . Both the Soxhlet and the SOXTEC methods show the same resu l t s .

In these studies it was also shown that the to ta l content of

extractable matter is generally higher with the SOXTEC system

than with the Soxhlet method. The differences between the two

methods are of course dependent on the solvent used,' the par t ic le

size and the duration of the extraction. For ultimate accuracy

the analysts are therefore requested to check the results achieved

on the SOXTEC system with official resul ts on the same samples.

Based on such data the extraction time in the SOXTEC system can

be adjusted to get directly comparable resul ts or a small correc-

tion factor can be applied. The la t t e r alternative is to be

recommended, when speed is of importance.

The influence of different laboratory technicians on the results was

tested in a small t r ial , the results of which are shown in table 4.

No differences were found.

Some samples may cause frothing in the extraction cups due to their fat

composition. To avoid this the temperature of the circulating water in

the Service Unit should not exceed 75 C, (usingdiethylether) . Another

cause of frothing is a too high fat concentration in the solvent. Therefore

we recommend lower sample weight if the fat content is high.

With low density samples such as cotton seed meal, the weight might have

to be reduced in order to prevent over filling of the thimble. The sample

in the thimble should not reach above the lower edge of the thimble adaptor.

1980.01.15 RA/ML m 23/8Q

TABLE 1

Comparison between two different extraction times on SOXTEC

SAMPLE

Pigfeed

Pigfeed

Pigfeed

Cattle

Cattle

Cattle

Poultry

Poultry

Coconut

Cotton

Oats

I

II

III

f eed I

feed II

feed III

feed I

feed II

oil meal

oil meal

Fish meal

Corn

-

10 +

2.26

3.50

2.32

3.23

5.82

5.84

2.34

4.29

15.88

8.96

3.66

11.25

1.98

5 0 X

20 minutes

2.25

3.39

2.31

3.39

5.83

5.99

2.35

4.36

16.21

8.85

3.68

11.52

1.98

X

2.26

3.45

2.32

3.31

5.83

5.92

2.35

4.33

16.05

8.91

3.67

11.39

1.98

T E

15 +

2.24

3.41

2.34

3.30

5.82

6.05

2.41

4.36

16.17

9.10

3.77

11.42

2.11

C

30 minutes

2.21

3.46

2.36

3.29

5.76

6.14

2.36

4.31

16.39

8.94

3.84

11.43

2.05

X

2.23

3.44

2.35

3.30

5.79

6.10

2.39

4.34

16.28

9.02

3.81

11.43

2.08

TABLE 2

Comparison between the SOXTEC and SOXHLET re su l t s from some different

labora tor ies .

SAMPLE

Pig feed I

Pig feed II

Pig feed III

Cattle feed I

Cattle feed II

Cattle feed III

Poultry feed I

Poultry feed II

Coconut oil meal

Cotton oil meal

Oats

Fish meal

Cornrel. error %

SOXTEC

2.23

3.44

2.35

3.30

5.79

6.10

2.39

4.34

16.28-

9.02

3.81

11.43

2.08

1.36

S O X H L E TLAB A

2.26

3.39

2.60

3.45

5.78

6.10

2.49

4.34

16.58

9.11

3.93

11.51

2.12

1.47

LAB B

2.39

3.74

2.86

3.47

6.00

6.16

2.79

4.64

16.83

9.26

4.20

11.75

2.13

1.69

LAB C

2.44

3.80

2.67

3.82

5.89

6.16

2.64

4.46

16.77

8.95

4.35

11.66

2.19

1.31

1980.01.15 RA/ML AN 23/80

TABLE 3

Linear regression with 9 5 % (t=2.20) confidence interval

at four fat levels (Gomparison against laboratory A)

F

Fat level S 0 X T E C

10+20 min 15+30 min

S O X H L E T

Lab B Lab C

2 %

5 %

10 %

15 %

1.8 - 2.0

4.8 - 5.0

9.6 - 9.!

14.6 -14.9

1.9 - 2.0

4.9 - 5.0

9.8 -10.0

14.7 -15.0

2.1 - 2.3

5.1 - 5.3

10.1 -10.3

15.0 -15.4

2.1 - 2.3

5.1 - 5.3

10.0 -10.3

14.8 -15.3

correl.

coeff.0.9995 0.9998 0.9997 0.9993

TABLE 4

Three samples analysed by two laboratory technicians on

the SOXTEC SYSTEM

Durationof extrac.

Lab. tech.

Sample I

Sample II

Sample III

30 min.

a

2.36 2.36

4.33 4.29

2.37 2.36

b

2.34 2.35

4.26 4.29

2.32 2.31

• 45 min.

a

2.39 2.33

4.33 4.35

2.38 2.37

b

2.36 2.35

4.31 4.36

2.36 2.34

1980.01.15 RA/ML AN 23/80