Analysis copper

Analysis of nitrogen contents could be an aid for estimating the chlorophyllin concentration, complementing the copper analysis. The Cu N ratio of 1.1 calculated based on a Cu content of 9.2% and N content of 8.1% must be re-evaluated because both Cu and N levels found in commercial preparations are significantly lower than theoretical values. 

Therapy may be monitored with a 24-hour urinary copper analysis periodically (ie, every 6 to 12 months). Urine must be collected in copper-free glassware. Because a low copper diet should keep copper absorption down to less than 1 mg/day, the patient probably will be in the desired state of negative copper balance if 0.5 to 1 mg of copper is present in a 24-hour collection of urine. 

The detection limits are calculated as three times the standard deviation obtained from the measurement of ten blanks. Ideally, we should have measured these detection limits from multiple measurements of a pure ceramic material to take into account the contribution of the ceramic matrix to the background but such a material does not exist. The detection limits range from less than 1 ppb to 2 ppm for copper (Figure 1). As the instrument is also used for copper analysis, it is likely that the high detection limit for this element is due to some contamination of the instrument. 

A 6-month-old infant has been fed unmodified cow s milk supplemented with com flour. He was healthy except that he was severely anemic, and an X-ray of his wrist showed retarded bone development. His hemoglobin was only 4.5 g/dL, and he had an elevated serum alkaline phosphatase. He was treated with iron supplements, folate, and ascorbic acid to no avail. Then serum copper analysis was done, and it showed a level of 9 fig/dL (normal is 85-163 /ig/dL). Thereupon his diet was supplemented with copper sulfate, and he showed dramatic improvement. Address the following questions ... 

Serum copper analysis was performed using a Perkin-Elmer atomic absorption spectrophotometer. Model 308. The previously described method by Prasad (136) was used after slight modification. For protein precipitation we used 7.5% trichloroacetic acid instead of 2N HCl used by Prasad. Analytical sensitivity for copper with this method was 0.2 jxg/ mL for 1% absorption and a relative detection limit of 0.005 fig/mL, Recovery studies done by adding known amounts of copper to the serum ranged between 96-104%. Analysis for ceruloplasmin was made by using commercially available immunodiffusion plates (Hyland, Inc. normal range, 20-35 mg/100 mL). Precision of the method has been tested by running 20 determinations for both copper and ceruloplasmin on one aliquot. CoeflBcient of variation did not vary by more than 3-5%. All samples were run in duplicates. 

Tissue concentrations of vitamins or trace elements are rarely measured in nutritional assessments because of the lack of availability of suitable tissue however, where such tissue is available, measurement may be helpful (e.g., copper analysis on liver biopsy of patients with suspected Whson s disease). 

Sht lamp eye examination may detect copper deposits in the eye (Kayser-Fleischer rings) and there may be abnormalities in liver frinction tests with an increased urine copper output (>500 fig Cu per L). Liver biopsy for copper analysis is useful in suspected cases and results above 250 fXg/g Cu dry weight are usually found (normal 8 to 40 Xg Cu per g dry weight). Failure of copper incorporation into plasma ceruloplasmin can also be demonstrated using an oral dose of stable Cu isotope. This may be helpful in excluding Wilson s disease when other tests are equivocal. Gene tracking and mutation detection are now possible, but since several hundred mutations exist this may not be informative. 

In the Americas, the minerals that contain copper occur chiefly in porphyry form (i.e., they are igneous in origin and are widely dispersed in the rock). In Africa and Russia, however, porphyry ores account for less than 20% of the total. In all areas copper ores have a relatively low copper analysis, in the range of 0.3 % Cu. Many mines operate today on ores of 1% or lower copper content. Thus, a significant consideration for economical... 

Willis (W12) has recently summarized the principles and applications of this method. A short note appeared recently regarding the use of atomic absorption spectrometry for serum and urine copper analysis (B15). The sensitivity of this method for copper is rather less than for such other biologically important trace metals as magnesium, zinc, and sodium. The sensitivity can be improved by extracting the copper as dithiocarbamate or pyrollidinedithiocarbamate complex (A7) into methyl isobutyl ketone. While this method is less sensitive than some others, it is nevertheless very specific and the apparatus is only moderately expensive. 

M.R. Callahan, J.B. Rose, R.H. Byrne Rose, Long pathlength absorbance spectroscopy trace copper analysis using a 4.4 m liquid core waveguide, Talanta 58 (2002) 891. 

Atomic absorption spectrometry (AAS) is still the work-horse method for copper analysis (WHO 1998). Detection limits are rather high with flame AAS, and even better results are obtained with graphite furnace AAS (Welz and Sperling 1999). 

Quantitatively transfer the solution from the previous ammonia analysis in part C to a 250-mL or larger beaker. Add 0.5 M aqueous ammonia, NH3, slowly from your buret until the pH of the solution is 9-10. Add 20. mL of the pH 10. buffer. If the resulting solution is cloudy, slowly with stirring add more buffer until the solution clears or until the total volume of added buffer is 30. mL. Quantitatively transfer the solution to a 500-mL volumetric flask, and dilute the solution with distilled water to the "mark." Mix the solution thoroughly. Rinse and fill your buret with this solution. Measure precisely 50.00 mL of the solution into a clean 250-mL Erlenmeyer flask. Add an additional 125 mL of distilled water to the flask, and heat the solution to 50-60°C (Laboratory Methods D). Add about 0.1 g of Murexide Tablet indicator (0.1 g is approximately the amount if you have 0.5 cm on the end of your spatula) to the flask. Be careful you should not add excess indicator. Clean the buret, and fill it with your standardized EDTA solution from part B. Titrate the warm metal ion solution with EDTA to a blue endpoint which persists for at least 30. seconds. Record the initial and final volumes of EDTA solution in TABLE 17.ID. Repeat the analysis with a second 50.00-mL portion of the solution from sample 1 in part C. Then repeat the copper analysis in duplicate again if a second sample is available from part c. 

If you do not stopper the EDTA solution with sufficient tightness, some water might evaporate before the solution is used. What effect would this problem have on your copper analysis ... 

There has been some debate concerning the occurrence of hop oil constituents in beer (see Chapter 13). Obviously some constituents will go into solution in beer that is dry-hopped but in the copper few components will survive the full period of wort boiling. Consequently many brewers make late additions of hops to the copper. Analysis of a Bavarian beer so treated, which... 

It is mandatoiy that samples for copper analysis be taken with all-plastic equipment. The use of a sampling bottle with bare brass, monel metal, or other copper alloys appearing anywhere at internal or external surfaces, will invalidate results. Stainless-steel straps and clips probably give no trouble. Samples should be transferred to polyethylene bottles for storage. We have no experience concerning the stability of samples in storage but, presumably, if they are frozen to —20 C and stored in the dark there will be no deterioration. Samples should not be filtered before analysis unless a soluble copper result is specifically required. 

Copper-rich waste discharged to lagoons behind an electroplating operation has percolated down to the water table, creating a plume of dissolved copper. Analysis of the porous medium and associated pore water indicate that the aquifer bulk density is 2.5 g/cm, porosity is 0.3, the copper concentration in the pore water is 10 mol/liter, and the copper concentration on aquifer solids is 10 mol/kg. If groundwater seepage velocity is 600 ft/yr, how fast will the plume advance ... 

Lin, J. Hobo, T. Chemiluminescence investigation of NH20H-fluorescein-Cu system and its application to copper analysis in serum. Talanta 1995, 42,1619-1623. 

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