Determination of Lead in Evaporated Milk by Atomic Absorption Spectrophotometry and Anodic Stripping Voltammetry: Collaborative Study

1973 ◽  
Vol 56 (5) ◽  
pp. 1246-1251
Author(s):  
John A Fiorino ◽  
Robert A Moffitt ◽  
Albert L Woodson ◽  
Raymond J Gajan ◽  
Glen E Huskey ◽  
...  
Keyword(s):  
Atomic Absorption ◽  
Anodic Stripping Voltammetry ◽  
Collaborative Study ◽  
Stripping Voltammetry ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Coefficients Of Variation ◽  
Anodic Stripping ◽  
Ppm Level

Abstract A method for the determination of lead in evaporated milk was successfully collaborated by 11 laboratories. Five laboratories used both atomic absorption spectrophotometry (AAS) and anodic stripping voltammetry (ASV) for the determination, 5 used only the atomic absorption method, and 1 used only the polarographic method. Each collaborator received 12 samples, 2 at each of the 5 different levels (0.06–0.95 ppm) and 2 practice samples with a known lead content. Both AAS and ASV were equally suitable for the determination of lead in the concentration range studied. The pooled variation between duplicate determinations was 0.0010 and 0.0016 for the AAS and ASV methods, respectively. For the AAS determinations the coefficients of variation (random error components) decreased from 43% at the lowest Pb level to 4% at the highest level. Although the ASV results did not show the same regularity of decreasing coefficients of variation with increasing Pb level, the coefficients of variation were acceptable: 28% at the 0.06 ppm level and 6% at the 0.22 ppm level. The AAS method has been adopted as official first action and the ASV method as interim official first action.

Lead in Evaporated Milk by Anodic Stripping Voltammetry and Atomic Absorption Spectrophotometry: Cooperative Interlaboratory Study

1978 ◽  
Vol 61 (4) ◽  
pp. 931-936
Author(s):  
Arlene M Sulek ◽  
Edgar R Elkins ◽  
Eric W Zink
Keyword(s):  
Atomic Absorption ◽  
Anodic Stripping Voltammetry ◽  
Lead Level ◽  
Stripping Voltammetry ◽  
Atomic Absorption Spectrophotometry ◽  
Double Blind ◽  
Absorption Spectrophotometry ◽  
Anodic Stripping ◽  
Normal Variability

Abstract The results of a cooperative study on the determination of lead in evaporated milk, using a double blind referee technique, are reported. This study was designed to determine the normal variability of methods currently used for lead analysis by canned food industry laboratories. Twenty-three laboratories participated in this study. Each laboratory was instructed to use atomic absorption spectrophotometry (AOAC 25.065), anodic stripping voltammetry, or carbon rod atomic absorption spectrophotometry. Overall, the results appear to be in close agreement with the spiking levels. The coefficient of variation for all laboratories was 36.0% at the 0.15 ppm lead level and 16.8% at the 0.40 ppm lead level.

Collaborative Study of a Method for the Atomic Absorption Spectrophotometric and Polarographic Determination of Cadmium in Food

1973 ◽  
Vol 56 (4) ◽  
pp. 876-881
Author(s):  
Raymond J Gajan ◽  
John H Gould ◽  
James O Watts ◽  
John A Fiorino
Keyword(s):  
Phase I ◽  
Atomic Absorption ◽  
Orange Juice ◽  
Collaborative Study ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Method ◽  
Acid Digestion ◽  
Absorption Spectrophotometry ◽  
Coefficients Of Variation

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.

Determination of Lead in Fish by Atomic Absorption Spectrophotometry and by Polarography. II. Collaborative Study

1972 ◽  
Vol 55 (4) ◽  
pp. 733-736
Author(s):  
Raymond J Gajan ◽  
Damon Larry
Keyword(s):  
Atomic Absorption ◽  
Collaborative Study ◽  
Atomic Absorption Spectrophotometry ◽  
Polarographic Method ◽  
Absorption Spectrophotometry ◽  
Paired Samples ◽  
Coefficients Of Variation ◽  
Different Types ◽  
Average Lead

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.

scholarly journals A Comparison of Two Methods for the Determination of Thallium in Urine

1983 ◽  
Vol 20 (5) ◽  
pp. 321-326 ◽  
Author(s):  
G J H Bessems ◽  
L W Westerhuis ◽  
H Baadenhuijsen
Keyword(s):  
Solvent Extraction ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Extraction Step ◽  
Analytical Recovery ◽  
Anodic Stripping

Two analytical procedures for the determination of thallium in urine are evaluated and compared. The two methods consist of differential pulse anodic stripping voltammetry and flameless atomic absorption spectrophotometry. Both procedures correlated well and were found to be acceptable in terms of precision and analytical recovery. However, a solvent extraction step proved to be necessary for the AAS procedure, and the linearity with respect to the concentration range was rather limited. The method based on DPASV is simple, accurate, precise, and sensitive and does not require any pretreatment of the sample. We therefore recommend the voltammetric procedure for the determination of thallium in urine, as described in this paper.

Analysis of Foods for Lead, Cadmium, Copper, Zinc, Arsenic, and Selenium, Using Closed System Sample Digestion: Collaborative Study

1980 ◽  
Vol 63 (3) ◽  
pp. 485-495
Author(s):  
Walter Holak ◽  
◽  
J Birri ◽  
G J Colonel ◽  
R O Hebert ◽  
...  
Keyword(s):  
Anodic Stripping Voltammetry ◽  
Collaborative Study ◽  
Stripping Voltammetry ◽  
Atomic Absorption Spectrophotometry ◽  
Potassium Nitrate ◽  
Sample Digestion ◽  
Absorption Spectrophotometry ◽  
Copper Zinc ◽  
Cadmium Lead

Abstract A method for the determination of cadmium, lead, copper, arsenic, selenium, and zinc is presented. This method involves digesting a food sample with nitric acid under pressure and using aliquots of the solution for analysis by suitable techniques. Cadmium, lead, and copper are determined by anodic stripping voltammetry (ASV) after heating with equimolar sodium nitrate/potassium nitrate; arsenic and selenium are determined by atomic absorption spectrophotometry (AAS) after generation of their respective hydrides; zinc is determined by conventional AAS. The combined recoveries and reproducibilities (CVR) of the collaborative study on this multielement analysis are: Cd, 89.14 (17.65) at 0.10–1.0 μg/g; Zn, 96.53 (5.59) at 16.7 and 66.7 μg/g; As, 99.50 (17.02) at 0.5 and 2.0 μg/g; Se, 95.17 (16.52) at 0.5 and 2.0 μg/g; Pb, 92.57 (15.22) at 0.3–3.0 μg/g; Cu, 108.39 (18.30) at 1.0–10.0 μg/g. The method has been adopted as official first action for cadmium, lead, arsenic, selenium, and zinc.

Atomic Absorption Spectrophotometric Determination of Lead, Cadmium, Zinc, and Copper in Clams and Oysters: Collaborative Study

1977 ◽  
Vol 60 (6) ◽  
pp. 1400-1407
Author(s):  
Stephen G Capar
Keyword(s):  
Atomic Absorption ◽  
Butyl Acetate ◽  
Collaborative Study ◽  
Atomic Absorption Spectrophotometry ◽  
Flame Atomic Absorption Spectrophotometry ◽  
Absorption Spectrophotometry ◽  
Flame Atomic Absorption ◽  
Coefficients Of Variation ◽  
Aspiration Technique

Abstract In the method studied, clams and oysters are dry ashed at 475°C, the ash is dissolved in dilute HNO3, and Pb, Cd, Zn, and Cu are determined by flame atomic absorption spectrophotometry (AAS). Sample solutions containing levels of Pb and Cd too low for direct AAS are extracted as the 1-pyrrolidinecarbodithioate complex into n-butyl acetate before AAS. The method was subjected to a collaborative study to determine the precision and accuracy of the analysis. Concentration ranges in the samples studied were approximately 0.06–2 ppm Pb, 0.03–2 ppm Cd, 40–600 ppm Zn, and 5–50 ppm Cu. Within these ranges, Cd levels <0.5 ppm and Pb at all levels required extraction prior to AAS. The average coefficients of variation for Pb, Cd, Zn, and Cu were, respectively, 66.0, 93.2, 8.5, and 20.5% for the lowest levels and 13.5, 3.8, 6.7, and 6.8% for the highest levels. Recoveries were computed by using the sum of the average collaborative results for the totally unfortified samples plus the fortification levels as the expected concentration. The average recoveries of Pb, Cd, Zn, and Cu were, respectively, 94.0, 99.7, 99.3, and 100.2 % for the lowest fortification level and 94.8, 95.6, 96.5, and 97.5% for the highest level. High levels of Cu and/or Zn caused incomplete extraction of Pb and Cd, with Cd being affected more severely than Pb. Data obtained also suggest that background corrections may be needed for determining Zn and Cd with the direct aspiration technique. No recommendation is made for official action.

Lead in Preserved Duck Eggs: Field Screening Test and Confirmation and Quantitation by Atomic Absorption Spectrophotometry and Anodic Stripping Voltammetry

1981 ◽  
Vol 64 (4) ◽  
pp. 1014-1016 ◽  
Author(s):  
Benjamin Krinitz ◽  
Nivia Tepedino
Keyword(s):  
Atomic Absorption ◽  
Anodic Stripping Voltammetry ◽  
Lead Level ◽  
Stripping Voltammetry ◽  
Atomic Absorption Spectrophotometry ◽  
Field Screening ◽  
Absorption Spectrophotometry ◽  
Laboratory Confirmation ◽  
Anodic Stripping ◽  
Egg Albumen

Abstract Analysis of preserved duck eggs in this laboratory by acid digestion and atomic absorption spectrophotometry has shown that addition of lead salts to the egg coating to speed the preservation process results in lead in the egg albumen and yolk. The lead levels decrease as the lead passes through successive membranes, i.e., the lead level in the yolk is lower than that in the albumen. A method has been developed for the field screening of preserved duck eggs for the presence of lead in which a portion of the egg coating is shaken with 4% acetic acid, and the resulting solution is tested by a modification of the AOAC dithizone method. A quantitative method for laboratory confirmation of lead in egg albumen and/or yolk has also been developed in which lead is determined by atomic absorption spectrophotometry or anodic stripping voltammetry after closed-system Tefloncup digestion with nitric acid.

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