Internal standard method of spectrographic analysis as applied to the determination of lead in high purity zinc

Abstract

tines are sfigtitly ttiirtrrcr. The rnnt.erinI was dcfitiitely deficietrt iic ptdssium nod probably slightly too low in ninng~rne~e to producc Tho strong' copper lines nre tlie result of bordeaux mixture yprnycd on the leaves to protect them froni blight nnd not removcd completely in the clenning process.SESSITIVITI-ASD ACCURACY OF JIETIIOD SOIIIC idea of t1i.e sensitivity nnd nccurncy of tho uiethod may bc gathered from the spectrogrnins No. 8 of spills impregtinted with ~1lougli of D s~rnclortl solution to sup~ily 04003 g. potnssium, 0.0003 g. cnlcium, 0.00006 g. mngncsiuni, O.ooOo6 g. sotlium, 0*000006 g. iron nnd 0.000001 g. ninngnncse, irnd by co~nparing spectrograms Nos. 8 nntl 9 hetween which there is n ten per cent. difference iu nmount of ench elcriierit coiiccriird. The mount of filter pnpcr burnt for spectrogrirnis contained nbout 0.000001 g. cnlciuni, m d ahont 0 .~~1 g. sotliuin. full ctop. . ' ' AORSOWLEDDIIEXTS ' The I~iiilding up o f this nicthod hCi s been bnsed Irrrgely on thc e'xpcncnrc of othcrs who used it in its rnrious stirges much more tlpn the writer. It wis accelerated Iiy the provisioli of urlclitio~ial ivnrkcrs uiidcr :k,&l!t mode by thr Xgricuiturni Xesearch b I i U C i 1 to nugtnelrt i i joint team coniposcd of the Biuclicinistry Scckiori of thc Enst Xnfliit): Hfsenrcli Stotion wid wurlicrs, inentioned below, front the Itescarcl Instittrtc of Plant I'hysiology, Iniprrinl College of' Scietice and Technolo~:y. A special debt is due to Major S. G. Thompson wlto uscd it it1 its cnrlieat nnd most troublesome stnges and who lind the iden of usiiig n coniniercinl oxy-ncetyletic blowpipe indepenclently of t.he writer. He 3130 invcstignted the possibilities nnd showed the value of thc method ng n inenns of dingnosis of mincrnl deficiencies in plnnts. Mrs. W. 0. Roberts t.rninec1 i~ number of nssistntits in its use :itid iupervised their routine work. Dr. 13. D. Bolas contributed the iden of wnxing the pnpers to innkc tlic folds of the spills stick together.Dr. D. tV. Goodrrll tins used the metliod xnninly for quantitative work. klr. niches usetl it for ib short tiinc. bliss 15. Ford Inns rfoirc routine rrnnlyses continuously for 34 years irtitl lies lrrtterly becri responsihle for the routine spcctrogrirphic ;iiitrly&, and mutine niinlysca hnvc been ilo~ic for n shorter le~igth of time by the hfisvcs