how to choose the right colorimetric analyzer - C&EN Global

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how to choose the right colorimetric analyzer V^RITICAL process decisions must often wait hours upon the result of a trip to the laboratory for a wet analysis. But for those determinations that can be performed colorimetrically, continuous, automatic endpoint analysis can now be performed right on the plant floor. New Milton Roy instruments continuously run through every step of a wet analysis in the parts-per-million— even parts-per-billion range without supervision. And any colorimetric analysis that fits these basic requirements can be automated:

1. No more than four reagents required. 2. All interfering ions can be eliminated. 3. No heating, filtering, extracting, or decanting needed. 4. Clean and clear samples and reagents. When to use the Quantichem® analyzer

Extremely sensitive Quantichem analyzers measure concentrations in parts-per-billion (ppb) ranges with accuracy approaching ± 3 % of full scale, and sensitivity of ± 1 % of full scale. Typical determinations include soluble silica (0-50 ppb), dissolved oxygen (0-30 ppb), copper, soluble iron, hydrazine, and others requiring up to four chemical reagents. A dual beam optical system and the use of two sample cells (one as a reference cell) eliminate all possibility of errors in measurement due to physical interference with the light path, different phototube aging characteristics, sample turbidity, sample color, and dirt on cell windows.

All the benefits of single-reagent automatic colorimetric analysis are provided by the simple, compact and inexpensive Chemalyzer analyzer. Recording is optional with this unit. 20

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"A completely automatic quantitative analysis lab" describes Quantichem colorimetric analyzers. The unit illustrated above analyzes silica in parts-per-billion concentration, safeguarding boiler and turbine at a major electric generating utility. Unique Minus Delta P® metering pumps, housed in the analyzer, meter up to four reagents with accuracies within ± 0.25%. Standard designs include a built-in limit alarm and circular or strip chart recorder with single or multiple recorders. As many as eight different samples can be sequenced through a single analyzer, with the analysis of each recorded on an eight-point strip chart recorder. Individually adjustable limit alarms are also available for each of the multiple samples.

a potentiometric type recorder with sensitivities of 10-60 mv may be wired quickly to recorder terminals inside the cabinet. The Chemalyzer is compact, easy to operate, and can be installed in minutes. It operates practically maintenance-free. All parts in contact with reagents are made of suitable corrosion resistant materials. Write for Bulletin 858-1

Write for Bulletin 1156-1

The high limit switch available in either instrument can be used to initiate control action directly or through relays. Typical functions include starting or stopping a controlled volume pump and starting an automatic regeneration cycle on a zeolite softener. Through the use of a proportional slidewire in the recorder, the Quantichem analyzer can automatically vary the capacity of a controlled volume pump, to increase or decrease the amount of chemical needed by the process.

When to use the Chemalyzer* analyzer

The Chemalyzer unit is designed for simple colorimetric analyses requiring a single reagent, such as water hardness, residual chlorine and phosphates. A simple inexpensive unit, it has no reference cell, and therefore requires samples free of turbidity and discoloration. Though there is no amplification of the measurement signal, concentrations of impurities are detectable to the parts per million range. One typical application for Chemalyzer instruments is monitoring effluent from zeolite softeners for hardness. At three or six minute intervals (as specified) a fresh sample of effluent is analyzed, and the ppm concentration of hardness is indicated on the face of the instrument. An optional feature is a high limit relay and switch to energize a red light whenever hardness concentration exceeds a pre-set limit. If recording is desired, "Tradename of Milton Roy Co., Phila., Pa.

How to control with Milton Roy analyzers

Write for complete data. Milton Roy Company, 1300 East Mermaid Lane, Philadelphia 18, Pennsylvania.

Controlled Volume Pumps • Quantichem Analyzers Chemical Feed Systems • pH Instruments