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TOC in water to a precision of ± 50 parts per BILLION New Products Yes. (And find it FAST) Within five minutes the well-accepted Dohrmann® TOC Analyzer determines or- ganic carbon in water. Now, new features expand its capability, making it the most versatile and rapid carbon in water instru- ment available to municipal and industrial laboratories. The DC-50 series, based on proven, EPA-accepted* methodology, now offers: Low level analysis: Model DC-52S is ideally suited for determining TOC in surface or drinking water. Using the sparge method, it measures extremely low levels of organics in water to a precision of ± 0.05 mg/1 (50 ppb) with 100% recovery. Analysis time: 5 minutes. Sample preparation time: 2 minutes. High level analysis: Model DC-52D meas- ures organics in water up to 6,000 mg/1 with a relative precision of ± 3 % . Even the most difficult samples — seawater, sludges, sediment — pose no problems. Measures all important volatile organics separate from residual organics. Broad linear range, 5-minute analysis, and a choice of sample handling methods are exclusive features. Whatever the application, whatever the budget, there's a DC-50 series analyzer for the job. For free 12-page brochure, call or write DOHRMANN DIVISION, 3240 Scott Blvd., Santa Clara, CA 95050. (408) 249- 6000. Telex 346 395. * Federal Register, Vol. 38, No. 199, Octo- ber 16,1973, WashingtonD.C. ENVIROTECH Student Spectrophotometer Model MSS-100 compact spectropho- tometer operates in the visible ranrje of the electromagnetic spectrum. A unique feature is its simultaneous dis- play of the transmission spectrum of a transparent liquid, gas, or solid and the measurement of the percent transmit- tance or absorbance of the object at any selected wavelength from 400 to 700 nm. The new spectrophotometer and workbooks provide an inexpensive means of comprehensive self-study or group instruction in the basic principles of absorption spectroscopy and color technology. $295. Macbeth, Div. of Kollmorgen Corp. 415 Probe Colorimeter Model PC/6000D digital probe colorim- eter for the monitoring of turbidity mea- surements uses a fiber optic light guide that transmits phase-shifted, AC modu- lated light to the probe tip. This light is then reflected by a mirror at the end of the tip. The amplifier has an electronic chopper synchronized with the light source, and as a result, ambient light cannot affect the readings. The large, bright seven-segment digital readout is convenient, eliminating reading errors. Brinkmann Instruments Inc. 416 CIRCLE 53 ON READER SERVICE CARD Model 1223A variable persistence/storage oscilloscope features a burn-resistant CRT and automatic storage control, 15-MHz bandwidth, and 2-mV sensitivity. It combines the advan- tages of variable persistence, to integrate very low frequency or low duty cycle traces into clear displays, with the advantages of storage for single-shot events. Maximum writing speed is 1 cm/Ms in the storage mode. Also included are an auto-erase mode and a variable control for brightness of stored traces. The 1223A includes TV sync, variable trigger holdoff, A ± Β modes, calibrated X-Y display, and select- able chop/alternate sweep operation. Power line voltage may be set at 100, 120, 220, or 240 V, and line frequency may be from 48 to 440 Hz. $2250. Hewlett-Packard Co. 403 FIND IT FAST IN THE ACS LABGUIDE The annual Labguide is the definitive directory to scientific instruments, equipment, chemicals, services, books, trade names and manufacturers. It leads all others in editorial pages, ad- vertising pages, and in reader usage. And, with 67,000 Labguides in service, virtually every laboratory has one or more copies within easy reach. The Labguide is where more than 160 suppliers say, "Here we are. Compare our products with those of our com- petitors." For example, you'll find ex- tensive product line catalog type ads in the 1976 Labguide from the following firms: Catalog Labguide Ads From: Page No. BAUSCH & LOMB 177 BECKMAN 41 DU PONT 103 MATHESON GAS 147 PACKARD 73 PERKIN-ELMER 155 PHILIPS 169 VARIAN 138 LABGUIDE The Labguide is your true one-stop buying source for scientific products. Centcom, Ltd., Advertising management for the ACS publications. 1174A · ANALYTICAL CHEMISTRY, VOL. 48, NO. 14, DECEMBER 1976
