Flame Spectrophotometric Determination of Microgram Quantities of Copper

Abstract

No detailed procedures have previously been published for the rapid, precise, and convenient determination of micro quantities of copper. Flame spectrophotometric studies at the copper line (324.7 µ) showed that the radiant power of copper was greatly enhanced by aspirating from an 80% methanol solvent. Interference studies indicated that nitric acid could be tolerated in appreciable quantities. Most cations show considerable radiation interference; however, the increase in the radiant power of copper caused by the addition of nine cations to standard copper solutions was determinable at a wave length of 325.1 mg. Inasmuch as no preliminary separations are necessary, the method is adaptable to routine determinations.The results are as accurate as conventional microchemical procedures.ALTHOUGH there are many publications on the determina-jTX. tion of alkali and alkaline earth metals by flame photometry, relatively few investigators have reported on the flame photometric determination of copper (1,3,(9)(10)(11)(15)(16)(17). Of these, only Dean (3) and Jordan ( 11) have described methods in detail. Dean (S) worked with nonferrous alloys containing copper in the range from 0.3 to 2.5%, and Jordan (11) analyzed for small amounts of copper in a hydrochloric acid extract of gasoline.Work by Dean and Lady (5,13) indicates that copper can be determined in micro quantities by flame photometry after a preliminary extraction of the copper as the salicylaldoxime with either chloroform or amyl acetate. Table I. Radiant Power of 4 per Ml. of Copper with Various Alcohols as Solvent Radiant Power, Scale Divisions0 Alcohol % Cu + ROH ROH Net Ci Methanol 95 54.2

Flame Spectrophotometric Determination of Microgram Quantities of Magnesium

“…Table III illustrates the effect of acids in 80% acetone containing 4 7 of magnesium per ml. The inhibition caused by phosphoric acid was not unexpected, inasmuch as other workers (7, [16][17][18] have reported a similar effect on the radiant power of other metals. radiant power of magnesium.…”

“…The following Beckman DU spectrophotometer settings were used throughout the investigation: act to obtain the maximum energy response. The procedure used to minimize instrumental errors has been reported (16).…”

Flame Photometric Determination of Copper in Mineral Mixes. Ion Exchange Technique for Sample Preparation

“…Dean (S) studied the influence of certain acids and certain cations on copper emission and found relatively little effect produced by the substances studied. Manna et al (10), however, found that H3PO4 inhibited copper emission in 80% methanol. They reported small effects produced by HC1 and H1SO4.…”

“…Others (2,8,10,11) have used flame excitation on a variety of samples. Of these procedures, only that developed by Dean (S) for nonferrous alloys did not require special treatment of the sample prior to introduction into the flame because of effects of extraneous Preliminary work in this laboratory on the flame determination of copper in mineral mixes prepared for use for the mixed feed industry indicated interferences with copper determination.…”