LECTURE 30 Application of AAS For Industrial Samples

 

Applicatons of Aomic Absorpton Specroscopy •

Course Title: Atomic Atomic Spectroscopic Spectroscopic methods Course Code: CHM-805 CreditthHours: 3(3-0) PhD 1   Semester By Dr.. AMBREEN Dr AMBREEN ASHAR

 

Atomic absorption spectroscopy •

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AAS is an analytical technique used to measure a wide range of elements concentration in sample. Atomic Absorption Spectroscopy is a very common technique for detecting metals and metalloids in samples AAS also play an important role in industry. industry.

 

Sample preparation for the determination of heavy metals in textile industry by AAS

 

Textil extilee industry industry •

The chemical substances or heavy metals in textiles cause allergic and toxic effects on human skin and their health including cause  breast cancer and lungs infections etc.

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These

chemicals

are

also

polluting

environment containing heavy metals.

our

 

Experimental   Sampling •

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The textile samples were collected from the various textile plants. Samples were dried at 105 ᵒC for 24 h. Dried samples were homogenized.

 

  Reagents •

Deionized water use for all dilutions.

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Suprapure quality of HNO3 and H2O2.

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Soak all glassware's and plastics with a 10 % (w/v) nitric acid solution overnight. a stock solution of 1000 mg mg/L /L for calibration.

 

  Apparatus •

graphite furnace using argon as inert gas.

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A Perkin Perkin Elmer Analyst 700 model AAS with

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deuterium background bac kground corrector. corrector. An air/acetylene flame.

 

Sample preparation •

Sample preparation is last step of analysis.

 dependence of sample preparation:  •

the sample preparation depends on:the sample.

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the matrix.

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the concentration level of the analytes.

 

Microwave digestion

 

Sample preparation for the analysis of Chromium inAAS textile materials by •

used in textile manufacturing as a catalyst in the dyeing process.

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as a dye for wool (chrome dyes).

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Also used in tanning leather.

 

 

Experimental  Sample:•

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a pure wool top. dyed with black chromium dyestuff at two different concentrations.

  Reagents:•

All the chemicals of p.a. grade.

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Distilled water.

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chromium standard solution for calibration.

 

 Apparatus •

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Use a perkin Elmer Elmer Analyst atomic absorption spectrometer. graphite furnace using argon as inert gas.

 

 Extraction Method:-

 

Determination of total chromium by means means of of Ashing procedure procedure The total chromium content in the solution calculated as follows:-

 

Sample preparation for the determination of heavy metals level ,Lead in cosmetics soap industry by AAS

 

What is soap and lead? •

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Soap  is a mixture of sodium salts of various naturally occurring fatty acids.

Soap is produced by a saponification or basic hydrolysis reaction of a fat or oil. Currently, sodium carbonate or sodium hydroxide is used to neutralize the fatty acid and convert it to the salt.

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Lead is the type of metal that has the bluish grey

color, it gets attention due to its toxicity .

 

Methods for sample preparation:-

In India, Lead determination in cosmetics  products was was carried out using the sample of of soap, shampoo, shaving creams and powder. Reagents:•

 Nitric acid(65%) acid(65%) .

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hydrogen peroxide (30%).

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Soap.

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Deionized water. water.

 

Methods for sample preparati preparation:on:•

 Determination of heavy metals in cosmetics can be done by preparing the sample either of these two methods:

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Wet digestion method Dry digestion method

 

Wet dige digestion stion met method: hod: •

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Use a mixture of 65% nitric acid & 30% hydrogen peroxide.   Destruction is done with 15ml of nitric acid, added to the destructive flask wh while ile heated at a tem temperature perature of about 100 °C. This process is carried out until the smoke is brown. After that solution is added with 30%hydrogen peroxide as much as 5ml while heating at a temperature of about 100°C. The destruction process is stopped until the clear suction indicates that the destruction process is completed. After it ,leave the solution to get cool , then put into 50mlvoulmetric 50mlvoulme tric flask and then homogenized it. At last perform the filtration.

 

Dry digestion:-

 

Sample preparation for the analysis of Glass and Ceramic frit for the determination of alkali and alkaline earth elements(Ba, Co, Cu, Fe, Pb, Ni, K, Na, Zn) to perform AAS Glass Ceramics:  Glass

ceramics are polycrystalline materials which are very fine grained, 0.1 micrometer in diameter in grain size and they are

 produced by controlled crystallization crystallization of base glass and that is why the name glass ceramic.

 

Glass Ceramic

 

How sample can be prepared for Glass and ceramic frit? •

Reagents Used:

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Concentrated Hydrochloric acid, conc. HCl

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Concentrated Hydrofluoric acid, conc. HF Strontium Chloride Solution

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Methyl alcohol

 

Standard Solutions:  All

standard solution are prepared by suitable dilution of the stock standard solutions under

standard conditions for each elements.  Dilutions should be made so that all dilute standards contain 0.6 M HCl and the alkaline earth standard solutions also contain 5 mL of the strontium chloride solution per 100 mL

 

Sample Preparation:  To

an accurately weighed 1-g sample in a plat platinum inum dish

 add

10 mL of HCl + 5 mL of HF

  If

the sample contains much boron, 10 mL of methyl alcohol also added  Evaporate the solution to dry salts.  Again

add 5 mL of HCl and evaporate the solution to

dryness

  Repeat

this process twice.

  Dissolve

the salts in 100 mL of 1.2 M HCl with heat and finally dilute the sample to 200 mL in a volumetric flask.

 

Conti…  Prepare

a suitable working solution by diluting the above solution with 0.6M HCl + adding

strontium chloride solution  So that the final dilution of the sample solution contain 5mL of the strontium chloride solution  per 100mL.

 

Sample Prepara Preparation tion for Steel industry by Atomic Absorption Spectrosc Spectroscopy opy  Steel industry is one of the essential industries

for the development of any community. In fact, it is really the base for numerous industries that could not have been established without steel industry. The European industrial revolution at the beginning of this century was actually founded on this industry.

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There are three basic routes to obtain finished steel products:

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 integrated steel production

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secondary processing

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 direct reduction.

 

Determination of vanadium in steels sample by graphite furnace Atomic Absorption spectro spectroscopy scopy The determination of vanadium in iron-rich samples such as steels can be effected using various procedures such as spectrophotometry, x-ray fluorescence spectrometry , neutron activation analysis , emission spectrography , inductively coupled plasma atomic emission spectrometry and  polarography . Despite the wide range of methods available, Increasing attention is being paid to the possibilities afforded by graphite furnace atomic absorption spectrometry (GFAAS) for the determination of low vanadium concentrations.

 

Experimental: •

Apparatus:

For GFAAS, GFAAS, a graphite furnace was coupled to a double beam atomic absorption spectrometer with background correction (GBC Scientific Equipment) •

Reagents Sample of steel 5g Concentrated HNO3 HCI

 

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Sampling:

  Was performed with a PAL-1000 automatic sampler capable of

delivering up to 5 ~1 of sample, with the option of up to ten multiple loadings. •

Back-extraction of vanadium

Back-extraction of vanadium from TBP into pure water was suggested by Majumdar and De . Several back-extraction reagents were tried, including ascorbic acid and H2O2. The latter forms a strong red-brown complex with vanadium and its use was tested in combination with distilled, deionized water and HNO3 or H2SO4 of various concentrations.

 

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The optimum back-extraction was achieved by use of 2% H2O2 in 6 M HNO3

 

Procedure: •

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Samples of steel (5 g) were dissolved under reflux in 20 ml of concentrated HNO3  This operation required only about 1o-15 min. After dissolution, the solutions were evaporated almost to dryness over a hot-plate and the residue was dissolved in 50 ml of 6 M HCl. The volumes were adjusted to 250 ml in a volumetric flask

 

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Samples of iron meteorites (1 g) were refluxed with 10 ml of HNO3 until dissolution was complete   The volumes were adjusted to 100 ml with 2 M HNO3. Aliquots (50ml) of this solution were evaporated to dryness and the residue was dissolved in 10 ml of 6 M HCI The aqueous back-extract was analysed for vanadium by GFAAS GFAAS using the conditions shown in Table 1.