THE ONLY TRUE MOLECULAR WEIGHT ANALYZER FOR GPC. ABSOLUTELY. TheLALLS Spectrophotometer From
MILTON ROY LDC DIVISION
GAS FACTS published periodically for analytical chemists
sion line derived from a third order polynomial equation by least squares. Quarter-to-quarter con sistency has improved markedly, while CV decreased steadily over the 12 years. These accomplishments Youden1 and others have recog were catalyzed by legislative nized that round robin testing mandate, improved pub can improve analytical accuracy. lished analytical procedures, The historical improvements increasing availability of described here should be of NBS Standard Reference interest to those seeking Materials and improved improvement themselves. instrumentation.
Detecting and correcting analytical error
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AVE RAGE
SUBSCRIBER CHANGE IN CV VVITH TIME
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03 4 1974
Milton Roy's LALLS detector series for size exclusion chromatography employs the proven principal of low angle laser light scattering to determine absolute molecular weights of effluents from a GPC. While other methods may provide inferential MW values only LALLS produces a direct and reproducible value for samples like thermoplastics, epoxy resins and biologicals. But you don't need to take our word for it; Milton Roy will perform a trial analysis on your material before you buy. MILTON ROY'S EXPANDED SERVICE NETWORK Now Milton Roy instrument
800-LDC-HPLC
service is available in most major cities. To get the benefits of absolute MW values in your GPC studies, just call or write: P.O. BOX 10235, RIVIERA BEACH, FL 33419 TEL800-LDC-HPLC · in FL(407)844-5241
8 12 1976
16 20 24 28 32 36 40 44 1978 1980 1982 1984 QUARTER NUMBER / YEAR
To assist analytical laboratories, Scott started a cross reference gas analysis program in 1964, handling all sample preparation, dissemination, statistical analysis and issuing of reports. The plot of coefficient of variation (CV) vs time excerpts 12 years from this study during which more than 100 industrial, government and independent testing laboratories participated. Separate curves for CO, C02, NO and total hydrocarbons were averaged and a regresl Youden. W. J., Graphical diagnosis of interlaboratory test results. Industrial Quality Control. 15. {5) 24-28 (1959)
Scott services now include natural gas, 0 2 , S02 and other compounds of environmental significance. If you want to learn how it may help you detect and correct unsuspected sources of analytical bias—and how subscribers can use it in litigation and for proving compliance—get in touch with Ron Geib at Scott.
INFORMATION HOTLINE: 800-331-4953 8:00AM-5:00PM Eastern Time In PA: 215-766-8861
Scott Specialty Gases Plumsteadville, PA · Houston. TX Fremont, CA · Wakefield. MA · South Plainfield. NJ · Troy. Ml · Longmont, CO · Baton Rouge. LA San Bernardino. CA
OIRCI F 37 ON READER SERVICE CARD
880 A · ANALYTICAL CHEMISTRY, VOL. 60, NO. 15, AUGUST 1, 1988
48 52 5 6 1986
CIRCLE 152 ON READER SERVICE CARD
