NEW CHEMICALS
NBS Standard Reference Materials The NBS Office of Standard Reference Materials has recently made available several new standards and the renewal of a low-carbon steel standard. The new standards are binary alloys of the tungsten-molybdenum and goldsilver systems intended for elemental microanalysis, and also a neutron flux monitor wire standard. The tungsten-molybdenum microprobe standard, designated SRM 480, is a composite of a core of W-20 wt% Mo alloy wire embedded in a pure Mo rod onto which a layer of pure W has been electroplated. The gold-silver microanalytical standard, SRM 481, consists of a series of binary alloy wires that range in nominal composition from 100% Au to 100% Ag bv steps of 20 wt%. SRM 953, Neutron Flux Monitor Wire is a cobalt-in-aluminum wire, 0.5 mm in diameter, of ultra-high homogeneity for which an accurate determination of the cobalt content is provided. The homogeneity is within ±0.001 w t % of Co. The renewal steel standard, SRM 131b, is a low-carbon silicon steel certified for its carbon content only. It nominally contains 20 ppm by weight of carbon, and is supplied in units of approximately 100 grams. Standards are available from the Office of Standard Reference Materials, Rm. B308, Chemistry Bldg., National Bureau of Standards, Washington, D.C. 20234 High Purity Inorganic Chemicals Included in a second group of ULTREX™ ultra-pure salts now available are ammonium acetate, ammonium sulfate, calcium carbonate, lithium carbonate, magnesium acetate, potassium chloride, potassium phosphate (monobasic), sodium bromide, sodium carbonate, sodium chloride, and strontium carbonate. They are packed in 100-gram vials, each of which will be accompanied by a detailed certificate of analysis. A typical analysis of ULTREX Potassium Chloride "would include data on: loss on drying, nonmetallic elements, and over 20 metallic impurities. Suggested applications include analytical standardization, biochemical studies, inorganic research, single crystal growth, and enzyme purification. J. T. Baker Chemical Co., Dept. J , Phillipsburg, N. J. 08865 501
KIT FOR THE SELECTIVE SILYLATION OF STEROIDS According to the method of Chamaaz & Homing!. With this new set of reagents you have a reliable and reproducible method for preparing volatile and stable derivatives of steroids and related compounds for gas phase analysis; knowing in advance just which active sites you will derivatize. This method will also be valuable for studies of derivative formation in synthetic work, structural determinations and separations other than gas phase. Recent Studies 1,2,3,4 have shown that various hydroxyl sites on steroids may be selectively converted to trimethylsilyl derivatives depending upon their relative steric hindrance. The conclusions reached in these studies were supported by GLC data and confirmed by Mass spectrometry. These sites fall into three distinct classes: unhindered, moderately hindered and highly hindered. Three reagents have been developed for the selective silylation of these sites: Tri Sil TBT will silylate all three types of sites; Tri Sil BT will silylate the moderately hindered and unhindered; BSA will silylate the unhindered groups. An additional reagent, 'MOX', may be used to form methoxime (MO) derivatives with ketones^, eliminating the possibility of enol-TMS ether formation in Ketosteroids. Three useful solvents, especially prepared for silylation reactions are included in the kit; acetonitrile, dimethylformamide and pyridine. No. 36300 Steroids Silylation Kit
Consists of the following, available separately at prices shown: No. 49016 TRI-SIL 'TBT', pKg of 10x1 ml ampules. .20.00
No. 49015 TRI-SIL 'BT\ pkg of 10x1 ml ampules.. .15.00 No. 38836 BSA, pkg of 10x1 ml ampules
12.50
No. 45950 MOX, 10 ml hypovial
12.00
No. 20062 Acetonitrile, silylation grade, 50 ml hypovial 2.50 No. 20672 Dimethylformamide, silylation grade, 50 ml hypovial 2.50 No. 27530 Pyridine, silylation grade, 50 ml hypovial 2.50 Ask for our technical Brochure."
'Steroids Silylation
References: 1. E. M. Chambaz & E. C. Horning, Analytical Letters, 1, 201-211 (1968). 2. E. M. Chambaz & E. C. Horning, Analytical Biochemistry, in press. 3. B. Maume, W. E. Wilson and E. C. Horning, Analytical Letters, 1, 401 (1968). 4. E. M. Chambaz, G. Maume, B. Maume & E. C. Horning, Analytical Letters, 1, 749-761 (1968). 5. W. L. Gardiner and E. C. Horning, Biochim. Biophys. Acta, 115, 425 (1966).
56.00 each
PIERCE CHEMICAL COMPANY P. O. Box 117 Rockford, Illinois 61105
(We will quote attractive prices for large volume users of this kit or its components) Circle No. 69 on Readers' Service Card
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PHONE 8 1 5 / 9 6 8 - 0 7 4 7
TWX
910-631-3419
See ACS Laboratory Guide for All Products/Sales Office
Gas chromatographers:
win
your own copy of The Rubber Handbook P O R A P A K ® m i c r o p o r o u s p o l y m e r G C c o l u m n p a c k i n g s are still so n e w a n d r e v o l u t i o n a r y that even w e d o n ' t k n o w e v e r y t h i n g t h e y c a n s e p a r a t e . S o w e w a n t to learn w h a t you have d o n e w i t h P o r a p a k . S e n d us a c h r o m a t o g r a m of a n u n u s u a l G C s e p a r a t i o n y o u ' v e m a d e w i t h P o r a p a k . If y o u r s is o n e of t h e t h r e e most i n t e r e s t i n g r e c e i v e d t h i s m o n t h , w e ' l l r e w a r d y o u w i t h a c o p y of The Rubber Handbook for your o w n home or office.* S i n c e its d e v e l o p m e n t just t h r e e y e a r s a g o , P o r a p a k has b e c o m e o n e of t h e most w i d e l y u s e d p a c k i n g m a t e r i a l s in g a s c h r o m a t o g r a p h y . R e a s o n s : N o l i q u i d p h a s e n e e d e d ; s t a b i l i t y at h i g h t e m p e r a t u r e s ; no b l e e d i n g ; s h a r p , s y m m e t r i c a l p e a k s w i t h e x c e l l e n t b a s e l i n e s t a b i l i t y ; easy c o l u m n p a c k i n g . W e n o w offer e i g h t t y p e s of P o r a p a k , i n c l u d i n g t w o d e a c t i v a t e d g r a d e s , f o r t h e w i d e s t r a n g e of p o l a r a n d n o n - p o l a r c o m p o u n d s w i t h b o i l i n g p o i n t s as h i g h as 3 0 0 ° C . N o w — h o w a b o u t t h a t c h r o m a t o g r a m of a s e p a r a t i o n y o u c o u l d n ' t have m a d e without Porapak? S e n d y o u r c h r o m a t o g r a m t o t h e a d d r e s s s h o w n b e l o w , a n d tell us w h e r e t o s h i p your prize. 4253
James L. Waters, President WATERS ASSOCIATES INC. 61 Fountain Street Framingham, Mass. 01701
WATERS ASSOCIATES
*P.S.: If your chromatogram isn't among the month's winners, you'll still get a pleasant "thank y o u " gift. Circle No. 171 on Readers' Service Card
Circle No. 143 on Readers' Service Card
VOL. 4 1 , NO. 4, APRIL 1969 ·
139 A
