Interpretation of the principle of infrared spectroscopic oil measuring instrument

Infrared oil measuring instrument is an instrument used in infrared photometry to measure oil. It is a high-tech product integrating optics, analysis, electronics and mechanics.

The instrument scans the absorbance value at \"3030-1, 2960-1, 2930-1\", the true measurement at three wavenumbers, long optical path, large energy, strong signal, and high signal to noise ratio, good stability.

The instrument overcomes the mechanical error caused by grating positioning, and the positioning and measurement are accurate.

The user does not need to make a standard curve, from zero to full scale, to build a platform or to calibrate during use, and the operation is simple.

Widely used in environmental monitoring, disease control centers, industrial and mining enterprises, scientific research institutions and other units.

Working Principle

When monochromatic light passes through the solution under test, its light energyI will be absorbed.

The intensity of the absorbed light energy is proportional to the concentration of the measured solution, according to Beer\'s law

A=log (1/T )= log(I0/I)

where: T----------Transmission

I0- --- - -----incident light intensity

I----------transmitted light intensity

A- --- - ----Absorbance

The formula for calculating the concentration of petroleum substances is:

C=X×A2930+Y ×A2960+Z× (A3030－A2930/F )

Where: C is the oil concentration

A2930A2960A3030 is the absorbance at different wavelengths

X, Y, Z and F are correction coefficients

First measure the total oil content C, then absorb the extract through magnesium silicate to separate and remove animal oilspolar oils and vegetables, and use the same method Measure and obtain the concentration of oil C oil, then the content of animal and vegetable oil is:

C animal and vegetable = Ctotal - C oil

Correction coefficient Calculation formula:

F=A2930(H)/A3030(H)

C(H)=X×A2930(H)+Y×A2960(H)

C(P)=X×A2930(P)+Y×A2960(P)

C(T)=X×A2930 (T) + Y×A2960(T)

+Z×[A3030(T)－A2930 (T )/F]

Where: H-------n-hexadecane

P-------- Pristane ( or iso octane)

T---------toluene (or benzene)

A------ -- - Absorbance at each wavenumber

Use carbon tetrachloride as a solvent to prepare solutions of benzene, isooctane and n-hexadecane, and the concentrations are 80 mg/ L, 20mg/L and 20mg/L respectively, use a 4cm cuvette to measure the absorption value of infrared spectrum. For the n-hexadecane solution, because its contentr in aromatic hydrocarbon is zero, i.e.:

A3030-A2930/F=0

p>

Measure the absorbance of n-hexadecane (H), isooctane (P) and benzene (T) solutions at wavenumbers 2930cm-1, 2960cm-1 and 3030cm-1, and bring them into the above formula can get X, Y, Z, F values.

Steps of use

Extracting part 1

Step 1: Pour all water samples at once into the separating funnel (glass vial for sample bottle)

Step 2: Add 50mlCCl4 to the sample bottle using a graduated cylinder (if the sample bottle is a plastic bottle, pour 50mlCCl4 directly into the separator liquid funnel), then close the bottle tightly, shake it by hand for 3 minutes and purge the air.

Step 3: Put the extract in a dry conical flask with a stopper and close the valve of the separatory funnel

Step 4: Add 5g of anhydrous sodium sulfate to the Erlenmeyer flask, close the cap tightly and shake. Observe whether it is crystallized, if it is crystallized, continue to add anhydrous sodium sulfate until it is possible to see that part of the powder and part of the crystal appear in the Erlenmeyer flask. (Let it sit for a while to observe)

Step 5: Put water in the measuring cylinder to measure the volume

Part 2 Measurement

1. Measure the total amount of oil in water

Pour the supernatant from the Erlenmeyer flask into the cuvette (2 /3) for direct measurement

2. Determination of oil in water

A. Add 5 g of magnesium silicate (60- 100 mesh) in the Erlenmeyer flask, then shake it by hand for 10 minutes or shake it The shaker takes 20 minutes.

B. Pour the liquid from the Erlenmeyer flask into the glass sand core funnel

C. Take thefiltered liquid and put it in the basin (2/3) Determination

3. Dosage of animal and vegetable oils in water

Oil total - petroleum = animal and vegetable oils

Note: 1. Erlenmeyer flask with ground neck must be dried

2. Magnesium silicate 60- 100 mesh

3. G1 sand core funnel (40ml)

Draw the standard curve of the infrared spectroscopic oil meter

Step 1: Draw 5ml of oil standard (1000mg/L) into a 50ml volumetric flask, and use the CCl4 solution to make up to the mark (shake)

Step 2: Put Take 0.5, 1, 2, 4, and 8 ml of the solution in the volumetric flask and put them in a 10 ml volumetric flask, and dilute until to the line with CCl4 (stirring)

Part 3: Standard Sample Determination

Tag: Infrared Spectroscopic Oil Meter