SLOPE SENSITIVITY UP
mV/MINUTE
START IHTEG
DOWN
STOP INTEG
The only GC Integrator with separate up-slope and down-slope controls...for optimum accuracy Until we introduced the 3370A, all GC Integrators had a single slope sensitivity control. This deficiency is no great handicap . . . when all your peaks are symmetrical. But in the everyday world of the chromatographer, tailing, overloaded and other asymmetric peaks are all too common. In all such cases, other integrators inevitably lead to inaccuracies because the single slope control cannot fit the ideal for both the up slope and the down slope. In the example, the integration of a tailing peak with another integrator results in a loss of area count, on the tail of the peak, equal to the black area (left). Integration of the same peak (right) with the 3370A and a lower down-slope setting completely eliminates the loss, resulting in a 2.8% increase in accuracy (9980-9700 -*• 9980) . . . while maintaining the up-slope setting at a level high enough to minimize false integration of noise. Separate up and down slope controls are only one of the reasons why the 33 70A performs more accurately than any other GC integrator. For the full story, call the nearest H P sales office, or write for Bulletin 3370. Prices start at $4950 including printer. Hewlett-Packard, Route 41, Avondale, Pennsylvania 19311 In Europe: 1217 Meyrin-Geneva, Switzerland.
74 C&EN
Single Slope Setting Area count: 9700
Separate Up and Down Settings Area count: 9980
HEWLETT^ Lhp] PACKARD ANALYTICAL
INSTRUMENTS
