TABLE 1 - EFFECT OF DIVERSE Ioxs IN THE ESTIMATIONOF VANADIUM

[Amount of V(V) taken, 75 [lg/25Ion added Tolerance Ion added

limit*([lgjml)

370250200350

3200t1300800

10001200

8401200120820450300

1000400680

ml]Tolerance

limit*([lg/ml)

1·01675

580280032004200

1·035009800

0·5800025002000

8001000220

Ni(II)Cu(II)CollI)Fe(III)Fe(III)Cd(II)Hg(II)Mg(II)Mn(II)AI(III)Mo(VI)W(VI)U(VI)Ti(IV)Zr(IV)Zn(II)Pb(II)As(III)

Pd(II)Pt(IV)Os(VlII)Ag(l)F-Cl-Br-1-NO;SO~-S20~-PO:-AcetateOxalateTartrateCitrateEDTA

* Amount causing an error of less than 2%.tIn presence of 800 [lgjml of tartrate.

TABLE 2 - DETERMINATIONOF VANADIUMINVANADIUMSTEEL

Steel Vanadium ([lg/ml) Relativesample error (%)

Certified Found*value

EO·300 0·4168 0·38 +0'0882·08 2·05 +0·0144·017 3'98 +0·0092

Tl00V25 1·034 1·021 +0'01250'4229 0'425 -0,0049

=Four determinations were carried out in tbe case of eachsample.

for 5 min and oxalic acid solution (O·OIN) was addedslowly with stirring until the pale-pink colour ofthe solution disappeared. The volume of thesolution was made up to 100 ml with doubly distilledwa ter. A suitable aliquot of the solution and 800V-g/ml of tartrate solution were taken in a 25 mlvolumetric flask and vanadium content estimatedusing the standard procedure. The results arepresented in Table 2.

MIs May & Baker (India) Private Ltd are thankedfor supply of pure DH. MIs Mohindra Ugine SteelCo. Ltd, Khopoli, are thanked for supply of thesamples of vanadium steel. .References

1. SANKE GOWDA,H. & SHAKUNTALA,R., Z. analyt. Chem.,80 (1975), 276.

2. SANKE GOWDA, H. & AKHEEL AHMED, S., Indian J.Chem. 15A (1977), 907.

3. SANKE GOWDA,H. & RAMAPPA,P. G., Indian. J. Chem.,13 (1975), 418.

4. SANKEGOWDA,H. & RAMAPPA,P. G., T'alanta, Z3 (1976),552.

5. SANKE GOWDA,H. & RAMAPPA,P. G., Anal. chim. Acta,84 (1976), 189.

6. SANKE GOWDA,H. & RAMAPPA,P. G., Z. analyt. Chem.,Z80 (1976), 221.

7. DWIVEDI, P. c., GURUDATHRAO, K., BHAT, S. N. & RAO,C. N. R., Spectrochim. Acta, 31 (1975)' 129.

NOTES

8. AYRES, G. H., Analyt. Chem., ZI (1949), 652.9. RINGBOM,A., Z. analyt. Chem., 115 (1938), 332.

10. SVEHLA,G. & TOLG, G., Talanla, Z3 (1976), 755.

Extractive Spectrophotometric Determination ofPd(II) with Sodium Ethyltrithiocarbonate

A. L. J. RAO & CHANDERSHEKHAR*Department of Chemistry, Punjabi University

Patiala 147002

Received 28 September 1976; revised 19 October 1977accepted 13 November 1977

Sodium ethyltrithiocarbonate has been successfullyused for the extractive spectrophotometric determi-nation of Pd(II). Carbon tetrachloride has beenfound to extract palladium quantitatively in the pre-sence of excess reagent in the pH range 1-10. Thecomplex exhibits absorption maxima at 370 and448 nm in the visible region. The system obeysBeer's law up to 6·Z Ilg Pd/rral and Sandell's sensitivityis 0·0083 Ilg Pd/crn", The method is simple, rapidand selective.

MANY colorimetric reagents have been proposedfor the determination of palladium=". The

presen t pa per describes a ra pid method for the esti-mation of microgram quantities of palladium usingsodium ethyltrithiocarbonate. The complex wasfound to be extractable in many organic solventslike carbon tetra chloride, chloroform, ethyl acetateand butyl c:cetate. Ca rbon tetrachloride was selectedfor the extra ction studies due to its lower volatilityand lesser miscibility with the aqueous phase ascompared to other organic solvents.

Erma spectrophotometer IS-7 and 1 cm glass cellswere used for absorbance measurements.

A standard palladium solution (9·4 X 10-3M) wasprep ared by dissolving palladium chloride (417 mg)in hydrochloric c cid (25 ml, 6M) and diluting to250 m!. Solutions for interference studies were ob-tained by dissolving appropriate salts in water togive 10 mg of the element per ml,

Sodium ethyltrithioce rbonate was prepared accord-ing to Atuki and Takada", Its solutions were pre-pared in water according to requirements.

Acetate buffer, pH 5'57, was prepared by mixing2M solutior..s of acetic c cid and sodium acetate inthe ratio 1: 9 v]v.

Procedure - To an aliquot of solution containing18-58 fLg of palladium were added acetate buffer(1 ml, PH 5·57) and sodium ethyltrithiocarbona te(1 ml, O·OIM) and the volume of the aqueous phasems de up to 10 rnl. Carbon tetrachloride (10 ml)w~s added and the two phases equilibrated for5 min. Both the pha ses were r llowed to settle for1 min and the optical density of the organic phasews s measured at 370nm, against similarly preparedreagent blank.. Fo~ the determination of palladium in some synthe-

tic mixtures, a number of ca tions C2 n be masked withfour-fold EDTA solution, volume of the aqueous

*Present address: Publications & Information Directorate,(CSIR), Hillside Road, New Delhi 110012.

463

INDIAN J. CHEM., VOL. 16A, MAY 1978

phase made up to 10 ml and the extraction carriedout as before.

The complex exhibits two absorption ma xima .The one at 370 nrn, having nearly three times thesensitivity of that at 448 nm, was selected for furtherabsorbance measurements. The pH-absorbanceprofile showed that quantitative extraction occurredbetween pH 1·0 and 10·0. The extraction of thepalladium complex is not enhanced if the amountof reagent is more than ten-fold. Absorbance dueto the extraction of palladium complex remainsunaffected by the variation of aqueous volumebetween 10 and 30 ml. It has also been foundthat shaking for 4 min was required for maximumcolour development in the organic phase. However,5 min of sha king has been selected as optimum.Absorbance of the organic extract due to 2 [.tgPdjrnl was found to be stable for 15 days. Saltingout agents such as sodium chloride, sodium nitrateand sodium acetate (0·01-0·08M), had no effecton the extraction of palladium complex. It W2S

observed that the extraction of palladium W2S

quantitative in a single batch extraction.Composition of the complex - The composition of

the complex was esta blished by the method of conti-nuous variations-" and mole ratio method!'. Obser-vations were taken at 370 nm and 448 nm. Thestudies showed that 1:2 metal-ligand complex isformed. Composition of the complex was furtherverified by the method of slope ratioI2,13.

Sensitivity and Beer's law range - The Beer's lawholds good upto 6·2 [.tg Pd/ml, The optimum rangeis 1·8-5·8 [.tg Pd/ml. The sensitivity is 0·0083 [.tgPd/cm- for log 10/1 = 0·001 at 370 nm and the corres-ponding molar extinction co-efficient is 1·277 X 10'.The sensitivity of the proposed method is cornpara bleto many well known methods for the determinationof palladium.

Effect of diverse ions - No interference was notedwhen 500-fold excess of sodium or potassium saltsof the following ions were present during the usualcolorimetric procedure: F-, o-. Br-; 1-, NOi, C20i-,S20;-, SCN-, C2HsOii, SO:-, CeHs07·2H203-, C,H40a•4H202- and EDTA. Also V(V), Mo(VI), W(VI),Th(IV), Cr(III), Ca(II), Mg(II), Ba(II) , AI(III) didnot interfere with the method. Mn2+, Zn2+, Cd2+,Fe3+, Ni2+ and C02+ were masked by using EDTAupto four-fold. Platinum interfered in the estimation.The results are accurate within ± 1·5%.

References1. AYRES, G. H. & MARTIN, J. B., Anal. Chim. Acta, 35

(1966), 18t.2. HEIT, M. L. & RYAN, D. E., Anal. Chim. Acta, 34

(1966), 407.3. TALWAR, U. B. & HALDAR, B. C., Anal. Chim. Acta,

39 (1967), 264.4. DALZIEL, J. A. W. & SLAWINSKI, A. K., Talanta, 19

(1972), 1190.5. FU]INAGA, T., SATAKE, M. & YONEKUBO, T., T'alanta,

19 (1972), 689.6. DAGNALL,R. M., EL-GHAMRY, M. T. & WEST, T. S.,

. Talanta, 15 (1968), 1353.7. BEAMISH, F. E. & McBRYDE, W. A. E., Anal. Chim.

A eta, 9 (1953). 349; 18 (1958), 551.8. BEAMISH, F. E., Talanta, 12 (1965). 743.9. ATUKI, K. & TAKADA, T.,Chem. A bstr. , 35 (1941),

3973.10. JOB, P., Ann .. Chim., 9 (1928), 113.

464

11. JOE, J. H. & JONES, A. L., Ind. Engng Chem. (AnalytEdn.), 16 (1944), 111. ' -.

12. HARVEY, A. & MANNING, D., J. Am. chem. Sac 72(1950), 4448. "

13. PIERCE, T. B. & PECK, P. F., Consideration of somemethods for the determination of the composition of aco!»p~ex l1/. a two phase system, Report, ChemistryDIVISIOn, AERER 4187. 1962.

separation & Quantitative Determination ofCu(I1) & Ni(II) with Salicylaldehyde

Hydr azcne

M. P. JAIN & SATYA KUMARDepartment of Chemistry, D.J. College, Baraut 250611

Received 25 March 1976; revised 8 November 1977accepted 31 December 1977

Cu(II) and Ni(U) have been estimated gravtmetrt-cally using an alkaline solution (1%) of salicylalde-hyde hydrazone as the precipitating reagent. Separa-tion of Cu(II) and Ni(II) from a number of cations hasbeen achieved ustng suitable masktng agents.

WE h~ve established earlier! that condensation of~alIcylaldehyde and hydrr zine gives two definite

and dlfferen~ compoU?ds, salicylaldehyde hydrazone(SH) and salicylaldczine (SA), m contrast to the con-tra~ictory and confused reports of earlier workerss-".

Literature st;rvey reve~ls that so far only Terentevet .al.3 ~ave tned. to estI:ma te copper and nickel byusing 1 Yo e~hanohc solution of the condensation pro-duct of salicylaldehyde and hydrazine and reportedthe unsuitability of the compoun~ ss an ~nalyticalreagent .. H<?wever, they were interpreting theirresults thinking the reagent to be SA while it actuallywas SH. Secondly, as observed by us later, the etha-nolic solution of SH is not very stable as it slowlygets converted to SA.

In the present study a method has been workedOt;t for ~he quantitative estimation of Cu(II) andNI(II) ~Ith. SH. By using suitable masking agentsand adjusting the pH, Cu(II) and Ni(II) can besepara ted from the other ca tions tha tare precipitatedwith SH, viz. Ag(I), Pd(II), Fe(II & III), Hg(II),Zn(II), Co(II),. Mn(II), Cd(II) and UO~+. Further,whl.le. determmmg the stability, solubility and com-position of these metal complexes, the earlier workof Terentev et al.3, Hunter et al.· and Ray5,6 has beenreviewed and discussed.

The. Cu(II) and Ni(II) complexes were preparedaccording to known methodsv". Both the com-plexes can be dried to a constant weight between110° and 160°. The metal and ligand contents weredetermined using standard methods=".

Cu(II) complex: [Found: m.p. 260° (d); lit.: 2580

(d)3; 270-75° (d)'; 2400 (d)S]Ni(II) complex: [Found: m.p. 3450 (d); lit.: 3500

(d)3; 313° (d)'; 2700 (d)5J.Both the complexes were found to be almost in-

soluble in common <?f!?nic solvents 3S reported byT~rentev et al.a, but It IS observed that freshly preci-~I~at~d meta I complexes have a pprecia ble solubi-Iities m benzene, chloroform and carbon tetra chloride