MICRO-TRACER ROTARY DETECTOR

The "Rotary Detector" magnetic separator is designed to separate Microtracers F from mixed animal and poultry feeds, premixes, or other dry granular or powdered products by a single or double pass of the sample through the instrument. This instrument is also

designed to separate Microtracer RF-Se-2% and RF-Se-4% from premixes, permitting analysis of such premixes for added selenium,

Micro-Tracers,Inc. manufactures two similar but different "Rotary Detectors", One is fabricated primarily with stainless steel and includes a very sturdy 230 Volt/ 60 Hertz motor, The second is

fabricated with plastic parts and will operate either on 118 or 220 Volt current or by battery. Both are packed in plastic carrying cases that fit under a seat on an airplane.

Each unit includes a lower cabinet in which a magnet is mounted like a potters wheel on a motor. One places a filter paper with a center hole punched in it on this magnet. The hole fits over a pin protruding from the magnet thereby locking the paper in place. One

then attaches the upper hopper to the lower cabinet.

While the magnet is rotating at full speed with the paper affixed, one slowly pours the feed sample to be analyzed into the upper hopper watching the feed exit through the funnel at the bottom of the hopper. If the funnel plugs, one inserts an artists fan brush

and probes the feed until it begins to flow. If necessary, one also taps the sides of the upper hopper to encourage the feed to flow.

The funnel of the upper hopper directs the feed over the rotating magnet in the lower cabinet. The Microtracer(s) is attracted by the magnet and lodges in a circular pattern on the filter paper as

does most other "tramp" iron. The feed passes over the magnet and is thrown to the side by centrifugal force and falls into the bottom bin of the lower cabinet.

More than 90% of Microtracer RF-Se-2% or Microtracer RF-Se-4% will be recovered in one pass through the unit with nearly 100% recovered in two passes. More than 98% of Microtracers F will usually be recovered from one pass through the unit.

1. Colored Microtracers F

a) For Qualitative Testing After one separates the magnetic material (Microtracers F as well as "tramp" iron) from the feed sample, take the upper hopper off the lower cabinet. The magnetic material should appear on the filter paper on the magnet as a ring of grey particulates.

Turn the unit on so the magnet rotates at full speed. With an eyedropper, dispense 5 to 18 drops of developer (water or water/alcohol) in the center of the rotating filter paper.

Turn the unit off. When the rotating magnet stops, color will usually be apparent as the dye from the tracer will have dissolved and colored the filter paper. After 30 seconds, transfer the paper to a hot plate or oven and dry it. This will "fix" the color from the tracer(s) in the filter paper so that discrete spots may be counted. If the paper is not dried, the color from the tracer(s) may diffuse so much that spots run into each other or the color is so light that it cannot be discerned with confidence. For certain pelleted feeds with added fat, the color may not

dissolve from the tracer particles unless or until the paper is heated at 300 degrees F, This may be necessary to dissolve the fat coating the tracer particles. Unless the fat is dissolved, the tracer developer cannot reach the dye of the tracer particle and a "false negative" can be the result. In some instances, it may be necessary to use DMSO (dimethlysulfoxide) or a solution of 50% DMSO/50% ethanol as a developer to dissolve the fat to obtain a valid tracer result.

b) For Quantitative Testing

After the magnetic material (including the Microtracer(s) F is isolated on the filter paper on the rotating magnet, one does not develop the tracer spots on the magnet but rather transfers the magnetic material- to a weigh scoop, One then "demagnetizes" these particles with a bulk tape eraser(available from Micro-Tracers,Inc. or Radio Shack) and then sprinkles the material onto a 15 or 24 cm. Whatman #1 filter paper wetted with developer (Water or water/alcohol). When spots begin to develop, the paper is dried and when dry marked for identification and the spots counted.

For colorimetric measurement of Microtracers F, one does not develop the tracer spots on the filter paper on the rotating magnet but rather transfers the material to a small test tube. One then adds 18 mis of water or water/alcohol developer to the test tube and agitates the tube to dissolve the dye from the tracer. The liquid is then filtered with the intensity of the color determined on a spectrophotmeter.

For further information on the quantitative determination of Microtracers F, please refer to literature Items "O"Quantitative Determination· of Microtracers F and to Item"M" Colorimetric Determination of Microtracers F.

c) Microtracers RF-Se-2% and RF-Se-4% in Feed PremixesA premix formulated to contain 0.1% Microtracer will contain 1,000 ppm added tracer iron. The "noise" level of iron in feeds averages between 20 and 150 ppm. For such a premix, the iron may be isolated from the premix sample and weighed giving an accurate measure (by inference) of the selenium added to the premix.

The premix sample is poured through the Rotary Detector twice with the magnetic material isolated on the filter paper on the rotating magnet. This material is transferred to a 30 ml analytical scoop. This scoop is held tightly to a large flat magnet and one blows gently into the scoop. One thereby blows away non-magnetic material without dislodging the tracer. The magnetic material is then weighed on an analytical balance and the selenium content of the premix calculated. Please refer to literature Items D and DD for further information.

The Microtracer RF-Se-2% or RF-Se-4% may also be analyzed chemically if the premix sample is fresh. Please contact Micro-Tracers,Inc. for information on this "quick" chemical assay.