NEW CHEMICALS
WHEN YOU WANT TO BE SURE that your fuel supplies are within prescribed limits for SULFUR
Single crystals, grown by the Czochralski, Bridgman, float zone, and vapor phase techniques are available in rod, disc, and sphere form. Prices range from $40 to $600. Crystals can also be fabricated to special shapes. A 15-page brochure gives complete in formation on sizes, shapes, and puri ties. Imanco. 914-356-3331 501 Pure grades of mercury are packaged in heavy glass bottles coated with a thick skin of polyvinyl chloride which makes the bottles shatter-proof and avoids mercury spillage in the lab. The 1-lb bottle has a handy pouring spout with its own screw cap. Two grades, M-140 redistilled mercury and M-141 instrument grade mercury (99.9995% pure), are available. Fisher Scientific Co. 412-391-1330 502 Mercury-labeled compounds for use in pollution studies are now available. Technical literature features methyl mercury chloride and phenyl mercury acetate at extremely high specific ac tivity and radiochemical purity. Infor mation on request. New England Nu clear Corp. 617-426-7311 503 Enzymes, in bulk, for use in clinical diagnostic tests are available. Glucose6-phosphate dehydrogenase, hexokinase, and urease are among the list. Free samples for evaluation and a bro chure describing the company's full line of enzymes and radiochemicals are available. Biochemical and Nuclear Corp. 213-849-1788 504 Reagent grade 1-pyrrolidinecarbodithioic acid, ammonium salt, a key re agent for trace metal analysis by atomic absorption, is now available with im proved information. Additional infor mation given in the label analysis in cludes assay, insoluble matter, melting point, and a sensitivity test indicating its suitability as a metal extract. This reagent forms complexes with many polyvalent metals, such as cadmium, copper, mercury, arsenic, and anti mony. Also available is a new reagent grade of brilliant green for photometric use. To ensure suitability for the de termination of antimony, each lot is controlled to an absorptivity specifica tion at 625 nm of a minimum of 1250 l./g-cm. This reagent is also offered as an acid-base indicator with a color change interval of pH 0.1 (yellow) to 2.6 (green). J. T. Baker Chemical Co. 201-859-2151 505
You can rely on sulfur values as determined by the PARR bomb combustion method using ASTM D129, D271 and related standard techniques. All of the equipment you will need to determine sulfur, halogens and other elements in combustible solids and liquids is provided in the PARR 1901 Oxygen Bomb Combustion Apparatus. Spec. 1900 gives complete details. May we send you a copy?
PARR INSTRUMENT
COMPANY
211 Fifty-Third St. Moline, III. 61265 Telephone (309) 762-7716 CIRCLE 140 ON READER SERVICE CARD
Di-n-butyt ether alone
S H I F T REAGENTS RESOLVE Ν M R SPECTRA
Ui-n-Dutyi etner w i t h Euroshift-F. Just a year ago we first offered Euroshift and Prashift, [ E u ( D P M ) 3 and Pr(DPM) 3 the Dipivaloylmethane complexes of Eu and Pr that produce dramatic shifts in H n.m.r. spectra [Sanders and Williams, Chem.Comm. 1183, (1970).] These reagents enable the simplification of confused spectra by spread ing the peaks into a resolvable pattern. A few months later the fluorinated chelates, Euroshift-F and Prashift-F [Eu(fod)3 and P r ( f o d ) 3 l , the metal complexes of heptafluorodimethyloctanedione, were shown to produce even more dramatic results [Rondeau and Sievers, JACS, 9 3 , 1522 ( 1 9 7 1 ) ] . The greater solubility and Lewis acidity of the H(fod) chelates allows higher molar ratios to be used and coordinates w i t h weaker donors such as ethers and esters.
Our years of experience in producing these types of chelates enables us to supply you the most reliable materials immediately, and at a price that has also shifted dramaticallydownfield, of course! In Stock for Immediate Delivery as follows: 118563 118566 114400 114010 ι ιυ^ο
each Euroshift [Eu(DPM) 3 ] $12/g Prashift [Pr(DPM) 3 ] ι or Euroshift-F [Eu(fod) 3 J $50/5g Prashift-F [Pr(fod) 3 ] aniTt is.it, i g o i eacn aDove $40/Kit
PIERCE CHEMICAL COMPANY P.O. Box 117 Nocktord, Illinois 61105 U.S.A. PHONE 815/968-0747 TWX 910-631-3419
CIRCLE 1 4 5 O N READER SERVICE CARD
ANALYTICAL CHEMISTRY, VOL. 43, NO. 10, AUGUST 1971
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