Metrohm.docx

MICRO DEVICES METROHM LTD.

ION ANALYSIS

Reagents : 0.05 M Potassium Ferricyanide ,o.1 M NaOH , 5 % Setamol WS ( Dispersing Agent) Apparatus: Titrino

801 Stirrer , 800 Dosino ( 20 ml & 10 ml ) Separate Pt. ring Electrode6.0351.0

Ag/Agcl/3M KCl reference Electrode , Titration Vessel, Titration Head. Sample Preparation : Take 100 ml water in 250 ml Beaker 0.125 gm Setamaol EWS, 1 gm Indigo Dye sample, 1.25 gm NaOH , 2.25 gm Hydro added gradually & Kept Stirring for 1 hr. Whem greenish ORANGE col.observed make 250 ml. with water . Keep for Setting. Solution turn ORANGE col. Analysis : soln.

Take 20 ml water in beaker .Add 1 ml. Setamol 10ml NaOH purged with N2 for 5 min inside the Pipetted out 10ml dyebath sample &continue purging N2 while titration.

Two End points observed Formula :

(1) HYDRO Content

(2) Diff.between Ist & IInd EP- Indigo Content

HYDRO Content gpl = EP 1 x 4.9 / Sample size ml. INDIGO Content gpl = ( EP 2 _ EP 1 ) x 6.557 / Sample size ml

Excess NaOH ( Alkalinity ) Hydrosulphite & Leuco Indigo in indigo Dyebath Reagent : 0.1 mol / ltr HCl , K 3 Fe ( CN ) 6 0.01 mol/ltr , N2 gas from Pressuring Flask , Apparatus : Titrino /Titro processor ,Magnetic Stirrer, Exchange units, Pt. titrode with Electrode cable , Titration vessel & its head , Gas inlet & overflow tube. (A) Alkalinity : Take 20 ml dist. Water & deareate it by bubbling thro’ N2 for 2 to 3 min. Add 0.5 ……5 ml sample & Titrate with 0.1 mol/ltr HCl Note Endpoint EP1 0.1 mol / ltr = 1 ml HCl = 4.0 mg NaOH gpl NaOH = EP 1 x C 01 / C 00 COO-Col.sample 4 ml (B) Hydro & Leuco Indigo Take 20 ml dist.water in beaker & deareate it by bubbling thro’ N2 for 2 min. Add 0.5 ……….5 ml sample dye solution & titrate in MET –mode for titrator . 0.2 ml steps 5 sec waiting time with cyanoferrate ( III) using Pt. Titrode. There are two endpoints . EP 1 – for Hydro sulphite

EP 2 – For Leuco Indigo

1 ml K3 Fe( CN )6 = 0.1 mol / ltr = 8.705 mg Na2 S2 O4 =13.114 mg C6H10N2O2=15.412mg C6H10N2O2 Gpl Hydrosulphit = EP 1 x CO 1 / CO 0 Gpl Leuco Indigo = ( EP2-EP1) x CO2 / CO0

CO0- Sample size ml , CO1-8.705 ,CO2-13.114

Indigo mol.wt.=262 Factor=262/2=131, % Purity=96.3 then Mol.Wt=272 Factor=272/2=136 Hydrosulphite Mol.Wt=174 Factor =174/2=87,%Purity 89 then Mo.Wt=193 Factor=193/2=96.5 1Mol. Indigo= 1 Mol. Hydro : 272/193 , 1 gm Hydro = 1.41 gm Indigo , 1gm Indigo =0.71 gm Hydro K3[Fe(CN)6] Mol.Wt = 329

0.5 N or Molar =16.4 gpl , 0.1 N or Molar = 32.9 gpl

Indigo Testing Spectrophotometer Bausch & Lomb UV-VIS Spectronic – 21 Chem.Required : 30 % H 2 O2 60 ml 50 % H2O2  100 ml with Dist H2O Part – I Setting SP-21 for Indigo estimation & working out Optical Density OD Vs Indigo conc. In gpl 6 Diff. Indigo wt. were reduced to leuco indigo Indigo : Setamol WS : Caustic : Hydro = 1.0 : 0.3 : 1.2 : 1.8 Vatg. Temp:50- 60 o C, Time : 45 min Wt. of Indigo to yield gpl 1 , 2 , 2.5 , 3 , 3.5 6 Volumetric Flask each of 1 ltr capacity charged with 5 ml. 30 % H2O2 solution Transfer 5 ml Leuco Indigo to Vol. flask Shake for 2 min. dilute upto 1000 ml. The procedure ensures 100% colloidal solution of indigo with no tendency to settle SP-21 was set to transmittance 100 with dist.water at 610 nm. Measure Indigo conc.interms of optical density at 610 nm using SP-21 The absorbance ( Optical Density ) was read on digital display . A graph of optical density x axis Vs. Indigo conc. Y axis A Linear relation was observed The slope X / Y works out to be 6.65 PART –II Estimation of Indigo in indigo Dyebath 5 ml 30 % H2O2 was transferred into 1000 ml. Vol. Flask 5 ml of Deybath liquor transferred into 1000 ml vol.flask Contents of Vol.Flask shaken for 2 min. & dilution was made to 1000 ml with dist. Water The optical density was measured as per procedure at 610 nm. Calculation : Indigo gpl = Optical Density x 6.65

REDOX TITRATION Conditioner : NaoH- 4 gpl , 5.2 ml / ltr ( 50 % )

Setamol WS 1 gpl

Caustic

Be

Den

Conc.gpl

%W

1 gm =

38

1.36

445

32.8

0.735 ml

50

1.53

772

50.5

0.5645

Titration Method      

Take 50 ml conditioner in 100 ml beaker , Place in the redox probe , place oil over the surface . Take 5 or 10 ml dyebath thro’ pipette & introduce it under the layer of oil in the beaker From burette add K3 Fe (CN)6 at slow flow rate End Point col. Change - Honey Yellow ------> Dark Blue Note Burette reading & Redox Potential Draw titration curve & Find the concentration .

Calculation of Concentration : Conc. Of K3 Fe ( CN ) 6

C oxm = ------ mol./ltr

Consumption of K3 Fe ( CN ) 6 V erber= -------ml Factor 136 Conditioner volume V orl = ------- ml Resulting Value Conc. Of Leuko indigo C lk ind = ----------gpl Conc. Of Hydro C hyd = ------ gpl Conc of K3 [ Fe ( CN ) 6 ] C l kind x C hyd

= C oxm x Factor x V erbr / V orl

C oxm = 0.1m, F = 136 , V orl = 5 , V erbr = 2 C l kind = 0.1 x 136 x 2 / 5 = 5.4 gpl Hydro C oxm = 0.5 , F = 96 , V orl = 5 ml , V erbr = 2 C hyd = 0.05 x 96 x 2 / 5 = 1.93 gpl