7Jkûmm.... COMBINATION PH ELECTRODES

F o r s a m p l e s f r o m 0 . 2 m l to a t a n k f u l

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COMBINATION ELECTRODES,Thomas.Con­sisting of a glass electrode and a silver-silver chloride reference electrode sealed into a single body. Bulb wall thickness and strength provide a sturdier electrode than heretofore available.

The single !4-inch stem can be used with samples of small volume as well as with larger quantities and is more convenient for transfer by hand from sample to sample than bringing the sample to electrodes in a fixed position.

The glass electrode inner element is shielded from electrostatic effects and stray electrical fields by the KC1 solution of the reference electrode. Port is provided for KC1 refill. Liquid junction is made by a sintered oxide plug sealed into the side of the lower stem %-inch above tip.

The stable, fast response of this low resistance glass electrode and the short fixed distance between î î i . a n d t l i? reference electrode junction make the lhomas Combination Electrode particularly valu­able in avoiding endpoint overshooting in electro-metric titrations.* The compactness of the design permits use of small vessels and leaves more room for stirrers and buret tips. . electrodes a r e each 6 inches long. Upper section is ί^-inch diameter for use in standard electrode holders. Stem is }44nch diameter over the lower 4-inch length. Can be used with samples as small as <i.Z ml in narrow tubes.

Connector plug of the glass electrode fits into the jacks of most existing pH Meters, either directly or through available adapters. 4858-L15. Combinat ion Electrode, Thomas as above, 6 inches long, range pH 0 to 12, tem­perature range 0 to 75°C, with 30-inch shielded l e a d 40.00 4858-L60. Dit to , range pH 0 to 14 43.00

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*See H. V. Malmstadt and E. H. Piepmeier, Analytical Chemistry, Vol. 37, No. 1 (January, 1965), p. SU

Thomas Laboratory Electrodes, see 1968 catalog pages 468-473, 488. Thomas Industrial Electrodes, information upon request.

fÂomaù. ARTHUR H. THOMAS COMPANY Scientific Apparatus and Reagents

VINE STREET AT 3RD . P.O. BOX 779 « PHILADELPHIA, PA. 19105, U.S.A. Circle No. 72 on Readers' Service Card

92 A · ANALYTICAL CHEMISTRY. VOL. 4 1 . NO. 14, DECEMBER 1969

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