Standard Operating Procedure

Standard Operating Procedure (vario MACRO CHNS Analyzer) Sample Preparation •

Aggressive chemicals, acids, alkaline solutions, solvents, explosives or materials that can create explosive gas mixtures are explicitly forbidden.

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Brief sample chemistry must be known, which the client will provide.

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Samples (only solid sample matrix) should be well homogenized, ground and dried.

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Sampling area and sample preparation tools (tweezers, spatula, etc.) must be contaminant free and swept with acetone.

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Use tin foils or tin boats for sample packing.

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Counterbalance tin boat or tin foil so that the balance scale shows “0.0000”.

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Weigh sample (1 mg to 1g) and note down the required information in “Sample Weighing Log Book”.

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Add sample additive (WO3 powder) to the sample in ratio of 1:1.

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Close tin tightly above the sample with the help of tweezers and micro spatula and shape sample into a cube and press the air out.

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Make sure that no bits of tin foil protrude from the fold.

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Place prepared samples in appropriate sample trays.

Operation of the vario MACRO

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Note down the temperature and humidity of the working area. Ambient temperature should be between 15 – 350C while relative humidity should be 30 – 80%.

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Make sure that during operation of the equipment there will be no electric power failure. Generator and UPS must be ready in case of any power failure.

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Only well-trained and authorized persons are allowed to work on CHNS elemental analyzer.

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Check and note pressure from two stage regulators of oxygen and helium gas cylinders.

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Switch on PC with screen and printer, and wait for booting procedure to be ended.

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Remove carousel.

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Switch on the equipment by pressing green button inside the right side front door.

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The instrument will carry out a reference run of ball valve and carousel automatically.

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Replace the carousel.

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Load software by clicking “varioEL” icon.

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Turn on operation gases o

For helium gas cylinder, set pre-pressure approximately 2.0 bar so that inlet pressure gauge shows 1.25 bar.

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For oxygen gas cylinder, set pressure 2.5 bar.

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Open file “template” and save as with new name.

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Confirm that analysis mode is CHNS in “Mode” option.

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Set CHNS parameters by clicking “Options” → “Parameters” (See page 5 – 12 of operation manual).

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Observe in the status field, the furnace temperatures will rise up. Approximately 45 – 60 minutes are required for heaters to reach the set temperatures.

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Perform leakage test by clicking “Options” → “Miscellaneous” → “Rough Leak Check”.

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Position the pointer at the end sample number by clicking “Edit” option.

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Input data by clicking “Edit” → “Input” for blank, run-in and sample in following sequence:

Sample Name

Sample Description

blank blank blank blank blank blank “run-in” “run-in” “run-in” “run-in” “run-in” “run-in” “run-in” “run-in” “run-in” “run-in”

Without anything Without anything Without anything Without anything Tin boat Tin + additive Tin + additive + standard Tin + additive + standard Tin + additive + standard Tin + additive + standard Tin + additive + standard Tin + additive + standard Tin + additive + standard Tin + additive + standard Tin + additive + standard Tin + additive + standard

Sample Weight (mg) 1 1 1 1 1 1 0.5 1.0 2.0 4.0 6.0 8.0 10.0 20 30 40

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Method

Amount

glut 2 blank blind glut 2 glut 2 glut 2 glut 2 glut 2 glut 2 glut 2 glut 2 glut 2 glut 2 glut 2 glut 2 glut 2

6 – 12 2 1 4 2 2 1 1 1 1 1 1 1 1 1 1

Sample

Tin + additive + sample

blank

Without anything

According to sample nature 1

Glut 2

2

glut 2

6

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Save the file.

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Place the prepared samples in carousel according to sequence and note the carousel number in “Sample Weighing Log Book”.

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Start analysis by clicking “System” → “Auto”.

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Observe peak formation by clicking “Graphic View” button.

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After completion of analysis compute daily factor by clicking “Math” → “Factor”.

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Print out results by tagging the required samples.

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Save file.

Shutdown Procedure

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For short shutdowns (during analysis or breaks for one night or 2 –3 days, turn off He supply. O2 supply should remain open for flushing purpose. Click on “Sleep/Wake Up” option and select the appropriate shutdown conditions (see page 6-21 of operation manual).

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For longer shutdowns (lasting several days or weeks), cool down all heaters and wait until the temperatures are lower than 1000C (approximately 2 hours). For this purpose, set nominal temperature to 00C by clicking “Parameters”. Exit software program via System – Offline option. Turn off gas supplies, vario MACRO equipment and peripheral instruments.

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