Atomic Absorption Spectrophotometric Method for Determination of Water-Soluble Copper in Water-Insoluble Copper Fungicides: CIPAC Collaborative Study. Comparison with Bathocuproine Method

1981 ◽  
Vol 64 (1) ◽  
pp. 75-78
Author(s):  
F Sánchez Rasero ◽  
◽  
P G Balayannis ◽  
H P Beyers ◽  
E Celma ◽  
...  

Abstract An atomic absorption spectrophotometric (AAS) method was collaboratively studied by 8 laboratories from Africa, the United States, Australia, and Europe. The samples were dispersed in deionized water. After centrifuging and filtering, the water-soluble copper in the filtrate was acidified and measured by atomic absorption spectrophotometry, in an airacetylene flame, at 324.7 nm. The results from 7 laboratories were satisfactory and no unfavorable comments were received. Repeatability standard deviations ranged from 0.005 to 0.023, and reproducibility standard deviations ranged from 0.012 to 0.062. When compared with the bathocuproine method, the difference in bias between both methods is not significant. They were both adopted as full CIPAC methods, with the bathocuproine method as the referee method. Both methods have been adopted official first action.

1990 ◽  
Vol 73 (5) ◽  
pp. 721-723
Author(s):  
Robert D Parker

Abstract An atomic absorption spectrophotometric method for determination of polydimethylsiloxane (PDMS) residues In pineapple juice was collaboratively studied by 9 laboratories. PDMS residues are extracted from pineapple Juice with 4- methyl-2-pentanone and the extracted silicone Is measured by atomic absorption spectrophotometry using a nitrous oxide/ acetylene flame. Collaborators analyzed 5 samples Including 1 blind duplicate. Reproducibility relative standard deviations (RSDR) were 13.1% at 31 ppm, 6.9% at 18 ppm, 14.8% at 7.9 ppm, and 16.1 % at 4.9 ppm PDMS. The method has been approved Interim official first action by AOAC.


1965 ◽  
Vol 48 (6) ◽  
pp. 1100-1103
Author(s):  
C H Mcbride

Abstract The atomic absorption method studied last year was re-examined and extended to include calcium and sodium. The procedures were submitted to 16 collaborators for determination of Ca, Cu, Fe, Mg, Mn, Na, and Zn. Results for Ca and Na were discouraging; further study is recommended.


1967 ◽  
Vol 50 (2) ◽  
pp. 338-339
Author(s):  
Duane H Strunk ◽  
A A Andreasen

Abstract A collaborative study was conducted on the 'atomic absorption spectrophotometric method for measuring the concentration of copper in alcoholic products. In this method, the samples are aspirated directly into the burner of the instrument, and the absorhance values are converted to ppm copper by reference to a standard curve. Data show good precision and are comparable to those obtained by the ZDBT method. It is recommended that the atomic absorption method be adopted as official, first action.


1985 ◽  
Vol 31 (8) ◽  
pp. 1310-1313 ◽  
Author(s):  
R Homsher ◽  
B Zak

Abstract Of two sensitive complexometric reagents for the colorimetry of serum zinc that we investigated, one, 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP), was found to be a potentially useful compound for trace-metal determinations. It has a high molar absorptivity (120 000 L mol-1 cm-1) but is not convenient to use because it is not very soluble in water. The other reagent, a related pyridylazo compound, is 2-(5-bromo-2-pyridylazo)-5-(N-n-propyl-N-3-sulfopropylamino)phenol (5-BR-PAPS). It seems better suited for use in routine zinc determinations because, besides being water soluble, it has a higher molar absorptivity, 130 000 L mol-1 cm-1. Results by the proposed method developed with 5-Br-PAPS correlated well with those by atomic absorption spectrophotometry. The between-run CV for control sera was less than 5%; the within-run CV (same controls) was less than 4%.


1983 ◽  
Vol 66 (5) ◽  
pp. 1234-1241
Author(s):  
Luis F Corominas ◽  
Roberto A Navarro ◽  
Pedro Rojas ◽  
◽  
M Aihara ◽  
...  

Abstract A collaborative study was carried out to compare AOAC method 2.147-2.150 for determining sodium in fertilizers with the atomic absorption spectrophotometric (AAS) method. Twelve synthetic NPK samples, 6 pairs of blind duplicates (0.06-8.5% Na), were sent to 22 collaborators; a total of 13 sets of results were received and evaluated by the modified matched pairs technique. The AAS method showed better performance in samples with low sodium content and high potassium content. The AAS method has been adopted official first action for determining sodium in fertilizers.


1997 ◽  
Vol 80 (6) ◽  
pp. 1287-1297 ◽  
Author(s):  
Paul A Brereton ◽  
Paul Robb ◽  
Christine M Sargent ◽  
Helen M Crews ◽  
Roger Wood ◽  
...  

Abstract An interlaboratory study of a graphite furnace atomic absorption spectrophotometry (GFAAS) method for the determination of lead in wine was conducted. Seventeen laboratories from France, United States, and the United Kingdom, using a variety of GFAAS instruments, took part in the study. The method incorporated a novel matrix-matching procedure to minimize matrix effects between standards and samples. Six wine test materials were prepared and sent to participants as 12 blind duplicate or split level samples. There was good agreement between results obtained from participants and target values (24–279 μg/L) obtained with an inductively coupled plasma-mass spectrometry method. The precision of the GFAAS method was well within the range predicted by the Horwitz equation for the 6 test materials analyzed. Repeatability standard deviations ranged from 3 to 17%. Reproducibility standard deviations were in the range of 10 to 30%. The method is recommended for use for official purposes.


1973 ◽  
Vol 56 (4) ◽  
pp. 876-881
Author(s):  
Raymond J Gajan ◽  
John H Gould ◽  
James O Watts ◽  
John A Fiorino

Abstract The method studied involves acid digestion, dithizone extraction, and determination by atomic absorption spectrophotometry and polarography. This study consisted of 2 phases, with 10 laboratories participating in Phase I and 15 laboratories in Phase II. The 12 commodities studied (lettuce, potatoes, orange juice, shredded wheat, milk, sugar, eggs, fish, frankfurters, rice, beans, and oysters) were spiked at 0.05, 0.1, 0.2, 0.4, 0.5, 1.0, 1.5, and 2.0 ppm cadmium. Only 3 collaborators submitted polarographic results. There were no statistically demonstrable differences for the atomic absorption method between spiking levels, commodities, or laboratories. Coefficients of variation were acceptable. The atomic absorption spectrophotometric method for determining cadmium has been adopted as official first action.


1972 ◽  
Vol 55 (4) ◽  
pp. 733-736
Author(s):  
Raymond J Gajan ◽  
Damon Larry

Abstract Nineteen laboratories, using 6 different models of atomic absorption spectrophotometers and 4 different types of polarographs, participated in this collaborative study. The average lead recoveries from 6 paired samples at 1–2, 5–6, and 10–11 ppm levels were 97.7% by polarography and 100.7% by atomic absorption. The average standard deviations were 0.32 and 0.41 ppm, respectively, and the average coefficients of variation were 7.9 and 13.1%, respectively. With collaborators reporting on both methods, the results of the overall method average were 4.3 ppm for polarography and 4.4 ppm for atomic absorption. Since there were no significant differences (p > 0.05) found between the method averages, except at one of the unspiked levels, the 2 methods can be used to confirm each other at levels of 1-11 ppm. The polarographic method has been adopted as official first action for the determination of lead in fish.


1968 ◽  
Vol 51 (5) ◽  
pp. 963-967 ◽  
Author(s):  
R H Abaza ◽  
J T Blake ◽  
E J Fisher

Abstract Accurate quantitative determination of oxalate in chemical analyses of edible plants is important because oxalate is a poisonous compound. The traditional KMn04-oxalate reduction-oxidation (Dye) method of analyzing for plant oxalate content presents two problems: (a) Plant pectins are not entirely separated in the determination of watersoluble oxalate and interfere in the oxidation of oxalate; and (b) a brownish-black precipitate containing ferrous iron is precipitated at the same pH as calcium oxalate and the precipitate interferes in determination of both water- and acid-soluble oxalate. Our modification of the Dye method consists of (a) using double-distilled water as the diluting medium, (6) increasing the acidity of the water-soluble oxalate medium after plant digestion to obtain complete removal of pectins, and (c) eliminating the ferrous iron-containing precipitate by filtration. Oxalate in the ferrous iron-containing precipitate is determined as calcium and magnesium salts by atomic absorption spectrophotometry; the value thus obtained is added to the oxalate value from the oxidation- reduction method. An indirect analytic method for oxalate, in which all of the oxalate was precipitated as the calcium salt and then measured by atomic absorption spectrophotometry, proved to be inaccurate


1972 ◽  
Vol 55 (4) ◽  
pp. 890-891
Author(s):  
Walter Holak

Caviar and dried apricots containing a known amount of added boric acid were subjected to a collaborative study. The samples were digested with sulfuric-nitric acid under reflux; the boron was then complexed with 2-ethyl-1,3-hexanediol and extracted into methyl isobutyl ketone. Boron in the organic phase was determined by atomic absorption, using a nitrous oxide-acetylene flame. The recoveries were satisfactory: 103, 95, and 93% for 300, 1000, and 1600 μg boron/g apricots and 95, 90, and 92% for the corresponding caviar samples. The method has been adopted as official first action.


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