Waters Corp

With large companies such as Waters Corp., TOSOH Corp., Polymer Laboratories Ltd., Shodex Corp., and Phenomenex Inc. and smaller companies such as American Polymer Standards Corp., Polymer Standards Service, and Jordi Associates, all manufacturing ST-DVB GPC/SEC gel, the market has become saturated with analogous columns. All the manufacturers just men-... 

FIGURE I l.l Resolution of a single pore size column and a mixed-bed column. Individual pore size columns deliver a significantly higher resolution than mixed-bed columns. The theoretical resolution of a single pore size column is compared to the resolution obtainable with a mixed-bed column. (Courtesy of Waters Corp.)... 

FIGURE 11.2 Selectivity of several individual pore size columns. This graph shows the resolution capability of Styragel HT 3, HT 4, HT S, and HT 6 columns. The selectivity [Eq. (I)] of these columns vs the molecular weight of polystyrene is plotted. (Courtesy of Waters Corp.)... 

FIGURE I 1.3 Analysis of poly(l, 4-butylene terephthalate) usinga Waters Alliance narrow-bore GPC system. Columns 4.6 X 300 mm Styragel HR 2, HR 3, and HR 4. Mobile phase hexafluoroisopropanol. 0.35 ml/min at 30 C. (Chromatogram courtesy of Peter Alden, Waters Corp.)... 

FIGURE 11.4 Comparison of chromatograms obtained on conventional (A) and solvent-efficient Styragel columns (B). In each case the column bank was a bank of Styragel HR 0.5, HR I, HR 2, and HR 3 columns at 3S°C with THF as the solvent. The sample is a mixture of polystyrene standards. With proper care and optimized instrumentation, good resolution can be obtained with solvent-efficient Styragel columns. (Courtesy of Waters Corp.)... 

FIGURE I 1.6 Calibration curves of Waters Styragel HR columns. (Courtesy of Waters Corp.)... 

The equipment consisted of two Waters (Waters Corp. Milford, MA) M-45 pumps, a Waters 481 UV detector, a six-port Valeo sampling valve (A2L6P) with 0.08" holes in the valve body and rotor, a Rheodyne Model 7413 injection valve with a 1-pl loop, a valve interface box, and a Digital Equipment LSI-11/23-based microcomputer system. The microcomputer was used to control all valves, collect raw data from the UV detector, integrate the chromatogram, and store and plot results. 

Waters Corp., Polyolefin Additives Determination with UV and Mass Detection, (Integrity System Publications), Waters Corp., Milford, MA (n.d.)... 

Figure 3.1 By using synthesis methods to control properties such as chemical and structural stability and porosity (dark sphere is porous white sphere is not), researchers can custom-make separation media for LC applications. These micrometre-sized spheres were made at Waters Corp.

Fig. 4.31. Cross section of a quadrupole (a) for the cyclindrical approximation and (b) for the hyperbolic profile of the rods. The electric field is zero along the dotted lines, i.e., along the asymptotes in (b). (a) Courtesy of Waters Corp., MS Technologies, Manchester, UK.

Waters CapLC System, Waters Corp., Milford, MA, April 2000, 72000133en. 

FIGURE 10 Separation of a neutraceutical mixture in phosphate- and formate-buffered mobile phases (courtesy of Waters Corp.). 

The author is grateful to Raphael Ornaf and Michael Dong of Purdue Pharma, and Connie Ye of Novartis Pharmaceuticals Corp. for their critical review and insightfnl comments. The author would like to acknowledge David Wn of Pnrdne Pharma for the data used in the discnssion of drng discoloration. The anthor also thanks Helen Yun of Pnrdne Pharma for her help in literatnre research, and Vladimir Binshtock of Waters Corp. for providing mnch needed technical information. 

FIGURE 5 (a) Peptide digest run on a 4.8-gm particle on a traditional HPLC system. Peak count is 70, and peak capacity is 143. (b) Peptide digest run on a 1.7-gm particle on the ACQUITY UPLC system. Peak count is 168, and peak capacity is 360. (Courtesy of Waters Corp.)... 

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