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Determination of cadmium in biological materials by atomic absorption
DETERMINATION MATERIALS
OF CADMIUM IN BIOLOGICAL BY ATOMIC ABSORPTION
PAUL A. ULLUCCIand JAEY. HWANG Apphcations Laboratory. Instrumentation Laboratory. Inc.. 113 Hartwell Avenue. Lexington. Massachusetts 02173, U.S.A. (Receitled
8 October
1973.
Accepted
4 December
1973)
Summary-A variety of brologtcal samples such as blood. urme, hair, nail and kidneys has been analysed cadmium. Tantalum ribbon flameless and conventional flame-aspiration atomicabsorption techrnques were employed for the analysis.
Among the heavy metals of toxicological importance, cadmium has received considerable attention. Some investigators have gone as far as saying that cadmium has probably more lethal possibilities than any other heavy matal.’ Cadmium is a common air and water pollutant, especially from smelters. It is also present in cigarette smoke.’ Diagnosis of cadmium exposure may be difficult. 3,4 With this problem in mind, the present work has been geared to the determination of cadmium in a variety of biological samples, especially with regard to micro-sampling. Four analytical techniques have been commonly applied to cadmium analyses, including ultraviolet and visible spectrophotometry, neutron activation, optical emission spectrography and atomic-absorption spectrometry.5 Of these techniques, atomic-absorption spectrometry has received the greatest attention because of its excellent sensitivity for cadmium. Pulido. Fuwa and Valee, using long-path absorption cells to increase sensitivity, were able to determine cadmium in urine and serum by direct aspiration.6 More commonly used atomic-absorption techniques involve chelation and extraction of cadmium into an organic solvent. Blood (after trichloroacetic acid precipitation of protein), urine, and tissue (after digestion with nitric-perchloric acid mixture and dissolution) are adjusted to a pH of 64-7.5, sodium diethyldithiocarbamate is added and then methyl isobutyl ketone (MIBK)’ is used for extraction. Other methods for tissue analysis involve acid digestion or dry ashing followed by acid dissolution of the residue and ultimately direct aspiration of the acid solution.4,8 All of these methods, however, require at least 5 ml of whole blood or l-2 g of tissue. Few microtechniques have been developed for the analysis of biological samples for cadmium. One recent method is based on solvent extraction in bloqd.’ No methods have been reported for the determination of cadmium in biopsy tissue. In this paper, methods are presented which have been developed for the determination of cadmium in urine by conventional flame aspiration atomic-adsorption spectrometry and in blood by flameless atomic-adsorption spectrometry. In addition, since some results have been reported concerning high levels of cadmium in hair from exposed animals5 a micro flameless atomic-absorption method has been developed for the determination of cadmium in organ biopsy samples. Assay of biopsy samples may be of significant value Presented at the 1973 Pntsburg Conference on Analyttcal Chemistry and Applied Spectroscopy. March, 1973. 745
PAUL A. ULLUCCIand JAEY. HWANG
746
in the light of previous data indicating that analysis of blood and urine may be of no value in diagnosing excessive exposure to cadmium.
EXPERIMENTAL Apparatus
All flame atomic-absorption measurements were made with an Instrumentation Laboratory (I.L.) Model 25302 Atomic Absorption Spectrophotometer. For the flameless atomic-absorption measurements. the burner head was replaced with an LL. Model 355 Flameless Sampler. Procedures for the optimization and use of the flameless sampler have been described previously. lo The background correction mode was used as described in the I.L. Instruction Manual. The operation and application of the background correction mode was described in earlier papers.’ ’ Important instrumental parameters are given in Table 1. Table 1. Instrumental parameters Spectrometer
Mode Hollow-cathode Lamp current
lamp A B A B
Photomultiplier Slit-width Wavelength Flameless
Automatic background correction Cadmium Hydrogen continuum 5mA lot0 15mA R372 (run at 530 V) 320 pm 228.8 nm
sampler
Mode Purge gas Gas flow-rate “Dry” setting “Dry” time “Analyze” setting Height of measurement
Automatic Argon 10 ft3/hr 4-5 turns 30-60 set 8.0 turns 2mm
Polypropylene test-tubes, 5 ml and 15 ml size (Falcon Plastics), were used throughout the sample preparations. The tubes were soaked overnight in 5?/, w/v Triton X-100 solution before use. Reagents
The following solutions were used in the present work. Formamide, Iv/, w/v ammonium pyrrolidinedithiocarbamate solution (APDC), 1% w/v saponin solution and water-saturated MIBK for blood analysis. For hair, nail and tissue dissolution, nitric acid (Baker “Ultrex”) and 10% v/v hydrogen peroxide were used. A 1000 &ml standard cadmium solution was prepared from cadmium metal.
Urine. Samples were collected in polyethylene bottles and acidified by addition of 10 ml of concentrated hydrochloric acid per 1. Blood. To O-1ml of heparinized whole blood were added one drop of I “/gw/v saponin solution 0.1 ml of formamide, 0.1 ml of 1% APDC, and 0.2 ml of water-saturated MIBK. The samples were mixed after each addition and for at least 1min following the addition of the MIBK and then centrifuged. The blank and cadmium standard of @005 Mug/ml,prepared from water and standard solution, respectively, were treated similarly. Hair and nails. Samples were soaked in 0.3% Triton X-100 solution for 30 min followed by three successive washes with the Triton X-100 solution and then three successive washes with demineralized water. then dried. To 10 mg of sample was added 1 ml of 8M nitric acid in a plastic test-tube. The tubes were capped lightly and placed in a water-bath at 80-90”. After 5-10 min, 05 ml of 10% hydrogen peroxide was added and the tubes were left in the water-bath for an additional 5-10 min, cooled. and diluted to a volume of 5 ml. Blank and standard (Cd @005 pg/ml) were prepared in a similar acid matrix. Tissue samples. A 5-10 mg portion of tissue sample was weighed into a plastic test-tube and I.0 ml of concentrated nitric acid was added. The tubes were capped lightly and placed in a water-bath at 80-90”. After 5-10 min, I.0 ml of 10% v/v hydrogen peroxide was added and the tubes returned to the water-bath for an additional 5-10 min. Blank and standard (Cd 0005 pg/ml) were prepared in a similar acid matrix.
Cadmium m biological materials
747
Urine cadmmm was determined by simple aspiration of the sample. The method of standard addrtions was used for standardtzation. For blood. hair. nail and ttssue analysis. 25 ~1 of the sample extract or solutton were placed on the tantalum rtbbon. For very low cadmmm levels. more sample. up to IO0 ~1, can be used.
RESULTS
AND
DISCUSSION
Contartrihatiort During the early stages of this work, severe problems were encountered with sample contamination when the flameless atomic-absorption technique was employed, because of the extreme sensitivity of atomic-absorption for cadmium (4 pg). Glass test-tubes were found unsatisfactory despite repeated soakings in acid and 5% Triton X-100 solution. Plastic tubes were far more satisfactory but still required cleaning. Soaking in 8M nitric acid overnight was found inadequate. However, excellent results were obtained when the tubes were soaked overnight in 5”/, w/v Triton X-100 solution. The tubes used were polypropylene with snap caps, which could be capped lightly during heating, thus preventing any loss. 16
Determlnotron
of
Cd in urine
(Direct osprrotionl
ta E
a
n
Bockground - correction
n
Non- bockground - correctron Fig. 1. Determinatton
mode mode
of Cd in urine.
Reagent-grade nitric acid was found to have a cadmium content of 5-10 pg/ml and could not be used, but Baker “Ultrex” nitric acid contained less than lpg/ml and was very satisfactory. The APDC. MIBK and other reagents used for the determination of cadmium in blood were found to be virtually free from cadmium contamination. Under the conditions mentioned above. very low blanks were observed in all cases. The determination of cadmium in urine has suffered considerable difficulty in the past from interferences by alkali metal salts in the sample. This has led to erroneously high values for cadmium in urine. 20-50 pg/15 Because of the high salt content, most urine cadmium analyses are performed by a solvent extraction technique. Figure 1 shows results for determination ofcadmium in urine by direct aspiration in the non-background-correction mode and the automatic background-correction mode. A significant amount of background signal is evident. This also shows the utility of the background-correction mode.
748
PAUL A. ULLUCCIand
JAE
Y. HWANG
Thus, use of the automatic background-correction mode coupled with high scale-expansion (100 X) and signal integration makes possible the direct determination of cadmium in urine. The cadmium value which we have obtained, 4 &l, is consistent with normal data previously published, Table 2. More data’concerning normal levels of cadmium in the body may be found in reference 5. Table 2. Normal
values of cadmium materials
in biological
Sample
Average
Range
Urine,14 m/l00 ml Blood,14 /q/I. Liver,’ ppm Kidney,’ ppm
0.85 1.6 2.03 11.2
0.3-50 05-l 1.0 1.19-3.71 21-220
Blood analysis
The extraction procedure presented here for the blood samples is merely an adaptation of a method used for the determination of lead in blood, reported earlier.‘2V’3 Results obtained from four normal blood samples by using the method described are given in Table 3. These results yielded a cadmium result of O-3 pg/lOO ml. The results presented for the normal blood samples are consistent with those previously published, Table 3. Lead can also be determined in the same extract. Table 3. Cadmium in whole blood (~/lo0 Sample Sample Sample Sample Sample Sample Sample
A* B B + 1.0 pg Cd/l00 ml C C + 1.0 pegCd/100 ml D D + 1.0 pegCd/100 ml
ml)
0.3 0.4 1.6 0.2 1.3 0.4 1.3
* Results for Samp.le A were verified by standard additions.
Hair and nail analysis
Analytical results obtained from the determination of cadmium in hair and nails are given in Table 4. In all cases, duplicate determinations gave good agreement. Normal levels of cadmium in hair are not well documented, since variations occur with sex, age, sampling site, colour of hair, and especially external contamination. The value of hair analysis as a measure of cadmium intoxication is not understood and is disputed.’ A IOmg sample of hair is used since at least this amount of hair is necessary for the sample to be representative. Ca, Mg, Na and K can be determined by aspiration in this same sample as well as Cu, Cr, Mn, Zn, Fe and Pb by flameless atomic-absorption. Tissue analysis
The most important analyses conducted were those performed on the tissue samples. The goal here was to establish whether or not biopsy tissue analysis could be used as a means of determining toxic exposure to cadmium. Autopsy samples of kidney and liver organs were sampled in triplicate from different portions of the organ. At the same time
749
Cadrmum m blological materials Table 4. Cadmium in hau and nails Sample
Cd,
Hair No. 1 Hair No. 2 Hair No. 3 Hair No. 4 Nails No. 9
Sample
ppm
4.1 3.7 1.0 0.8 1.7 2.5 2.4 2.3 25
Cd. ppm
Hair No. 5
3.2 2.4 3.4 4.5 4.5 4.9 I.7 0.32
Hair No. 6 Hair No. 7 Hair No. 8 Nails No. 10
a 2-g sample was taken from the organ for conventional flame-aspiration atomic-absorption analysis. The results obtained are summarized in Table 5. It is important to notice the large spread in the three different analyses of the same organ. To ascertain whether the range of values obtained was due to variation in cadmium concentration at different locations in the organ, or due to poor reproducibility of the method, NBS SRM No. 1157, Table 5. Cadmium m kidney and
liver autopsy samples. ppm
Cadmium Sample
Weight of sample, mg
A (Kidney)
9.8 5.2 10.3 18.4 18.2 13.8 21.2 11.0 12.5 12.7 11.5 8.5
B (Kidney)
C (Liver)
D (Kidney)
Flameless 127 150 167 42 64 92 2.2 4.8 2.8 2.1 4.4 5.3
Flame
150
69
3.0
5.0
bovine liver. was analysed by the method presented. The results of the triplicate cadmium determinations are shown in Table 6. The accuracy and precision of the analysis were found to be excellent and thus it is obvious that the variation in cadmium concentrations observed is attributable to the heterogeneous distribution of cadmium in the organ. Although a significant variation in cadmium concentration at different organ locations is Table 6. Accuracy and precision of method. (NBS SRM 1157 Bovine Liver) Present method. ppm* 0.27 f 0.02 0.27 + 0.02 0.25 * 0.04
NBS data.
ppm
0.27 f 0.04
* Results based on 50-mg sample and aqueous standards Precision data based on IO readmgs.
750
PAUL A. ULLUCCIand JAE Y. HWANG
apparent, this does not rule out the validity of the method as a diagnostic tool, since in the case of individuals suffering from cadmium poisoning a considerably higher than normal organ cadmium level is observed. Acknowledgement-The authors would like to express their appreciation to Dr. George Lewis and his colleagues at the Boston V. A. Hospital for providing the autopsy samples used in this work.
REFERENCES 1. 2. 3. 4. 5.
6. 7. 8.
9. 10. 11. 12.
13. 14.
F. C. Christensen and E. C. Olsen, Archives of Industrial Health, 1957, 16,8. M. J. H. Nadi, D. Stone and H. Jeck, Lancer, 1969,2, 1329. G. M. Fischer and G. S. Think, Arch. Enoiron. Health, 1971,23, 107. J. M. Morgan, ibid., 1972 24, 364. L. Freberg, M. Piscator and G. Nordberg Cadmium in the Environment. Chemical Rubber Company, Clevelan& 1971. P. Pulido, K. Fuwa and B. L. Vallee, Anal. Biochem., 1966,14, 393. E. Berman, At. Abs. Newsletter, 1967, 6, 57. A. S. Curry and A. R. Knott, Clin. Chim. Acta, 1970.30, 115. M. M. Joselow and J. D. Bogden, At. Abs. Newsletter, 1972 11, 127. J. Y. Hwang, C. J. Mokeler and P. A. Ullucci, Anal. Chem., 1972,44,2018. J. Y. Hwang, P. A. Ullucci and C. J. Mokeler, ibid., 1973, 45, 795. R. 0. Farrelly and J. Pybug Clin. Chem., 1969, 15, 566. J. Y. Hwang, P. A. Ullucci, S. B. Smith, Jr. and A. L. Malenfant, Anal. Chem., 1971,43, 1319. D. H. K. Lee, Ed., Metallic Contaminants and Human Health, p. 236. Academic Press, New York. 1972.
ZusuaannfLJsune-Eine Anzahl biologischer Proben wie Blut, Urin, Haare, N&gel, Leber und Nieren wurden auf ihren Cadmium-gehalt analysiert. Zu der Analyse wurden das flammenlos Atomabsorptionsverfahren mit Tantalband und das iibliche Verfahren mit Ansaugen der Probe in die Flamme verwendet.
R&&-On a analyd une varittk d’tchantillons biologiques tels que sang, urine, cheveux, ongles, foie et reins pour le cadmium. On a employ& les techniques d’absorption atomique sans flamme au ruban de tantale et a aspiration de flamme ordinalre.
OF CADMIUM IN BIOLOGICAL BY ATOMIC ABSORPTION
PAUL A. ULLUCCIand JAEY. HWANG Apphcations Laboratory. Instrumentation Laboratory. Inc.. 113 Hartwell Avenue. Lexington. Massachusetts 02173, U.S.A. (Receitled
8 October
1973.
Accepted
4 December
1973)
Summary-A variety of brologtcal samples such as blood. urme, hair, nail and kidneys has been analysed cadmium. Tantalum ribbon flameless and conventional flame-aspiration atomicabsorption techrnques were employed for the analysis.
Among the heavy metals of toxicological importance, cadmium has received considerable attention. Some investigators have gone as far as saying that cadmium has probably more lethal possibilities than any other heavy matal.’ Cadmium is a common air and water pollutant, especially from smelters. It is also present in cigarette smoke.’ Diagnosis of cadmium exposure may be difficult. 3,4 With this problem in mind, the present work has been geared to the determination of cadmium in a variety of biological samples, especially with regard to micro-sampling. Four analytical techniques have been commonly applied to cadmium analyses, including ultraviolet and visible spectrophotometry, neutron activation, optical emission spectrography and atomic-absorption spectrometry.5 Of these techniques, atomic-absorption spectrometry has received the greatest attention because of its excellent sensitivity for cadmium. Pulido. Fuwa and Valee, using long-path absorption cells to increase sensitivity, were able to determine cadmium in urine and serum by direct aspiration.6 More commonly used atomic-absorption techniques involve chelation and extraction of cadmium into an organic solvent. Blood (after trichloroacetic acid precipitation of protein), urine, and tissue (after digestion with nitric-perchloric acid mixture and dissolution) are adjusted to a pH of 64-7.5, sodium diethyldithiocarbamate is added and then methyl isobutyl ketone (MIBK)’ is used for extraction. Other methods for tissue analysis involve acid digestion or dry ashing followed by acid dissolution of the residue and ultimately direct aspiration of the acid solution.4,8 All of these methods, however, require at least 5 ml of whole blood or l-2 g of tissue. Few microtechniques have been developed for the analysis of biological samples for cadmium. One recent method is based on solvent extraction in bloqd.’ No methods have been reported for the determination of cadmium in biopsy tissue. In this paper, methods are presented which have been developed for the determination of cadmium in urine by conventional flame aspiration atomic-adsorption spectrometry and in blood by flameless atomic-adsorption spectrometry. In addition, since some results have been reported concerning high levels of cadmium in hair from exposed animals5 a micro flameless atomic-absorption method has been developed for the determination of cadmium in organ biopsy samples. Assay of biopsy samples may be of significant value Presented at the 1973 Pntsburg Conference on Analyttcal Chemistry and Applied Spectroscopy. March, 1973. 745
PAUL A. ULLUCCIand JAEY. HWANG
746
in the light of previous data indicating that analysis of blood and urine may be of no value in diagnosing excessive exposure to cadmium.
EXPERIMENTAL Apparatus
All flame atomic-absorption measurements were made with an Instrumentation Laboratory (I.L.) Model 25302 Atomic Absorption Spectrophotometer. For the flameless atomic-absorption measurements. the burner head was replaced with an LL. Model 355 Flameless Sampler. Procedures for the optimization and use of the flameless sampler have been described previously. lo The background correction mode was used as described in the I.L. Instruction Manual. The operation and application of the background correction mode was described in earlier papers.’ ’ Important instrumental parameters are given in Table 1. Table 1. Instrumental parameters Spectrometer
Mode Hollow-cathode Lamp current
lamp A B A B
Photomultiplier Slit-width Wavelength Flameless
Automatic background correction Cadmium Hydrogen continuum 5mA lot0 15mA R372 (run at 530 V) 320 pm 228.8 nm
sampler
Mode Purge gas Gas flow-rate “Dry” setting “Dry” time “Analyze” setting Height of measurement
Automatic Argon 10 ft3/hr 4-5 turns 30-60 set 8.0 turns 2mm
Polypropylene test-tubes, 5 ml and 15 ml size (Falcon Plastics), were used throughout the sample preparations. The tubes were soaked overnight in 5?/, w/v Triton X-100 solution before use. Reagents
The following solutions were used in the present work. Formamide, Iv/, w/v ammonium pyrrolidinedithiocarbamate solution (APDC), 1% w/v saponin solution and water-saturated MIBK for blood analysis. For hair, nail and tissue dissolution, nitric acid (Baker “Ultrex”) and 10% v/v hydrogen peroxide were used. A 1000 &ml standard cadmium solution was prepared from cadmium metal.
Urine. Samples were collected in polyethylene bottles and acidified by addition of 10 ml of concentrated hydrochloric acid per 1. Blood. To O-1ml of heparinized whole blood were added one drop of I “/gw/v saponin solution 0.1 ml of formamide, 0.1 ml of 1% APDC, and 0.2 ml of water-saturated MIBK. The samples were mixed after each addition and for at least 1min following the addition of the MIBK and then centrifuged. The blank and cadmium standard of @005 Mug/ml,prepared from water and standard solution, respectively, were treated similarly. Hair and nails. Samples were soaked in 0.3% Triton X-100 solution for 30 min followed by three successive washes with the Triton X-100 solution and then three successive washes with demineralized water. then dried. To 10 mg of sample was added 1 ml of 8M nitric acid in a plastic test-tube. The tubes were capped lightly and placed in a water-bath at 80-90”. After 5-10 min, 05 ml of 10% hydrogen peroxide was added and the tubes were left in the water-bath for an additional 5-10 min, cooled. and diluted to a volume of 5 ml. Blank and standard (Cd @005 pg/ml) were prepared in a similar acid matrix. Tissue samples. A 5-10 mg portion of tissue sample was weighed into a plastic test-tube and I.0 ml of concentrated nitric acid was added. The tubes were capped lightly and placed in a water-bath at 80-90”. After 5-10 min, I.0 ml of 10% v/v hydrogen peroxide was added and the tubes returned to the water-bath for an additional 5-10 min. Blank and standard (Cd 0005 pg/ml) were prepared in a similar acid matrix.
Cadmium m biological materials
747
Urine cadmmm was determined by simple aspiration of the sample. The method of standard addrtions was used for standardtzation. For blood. hair. nail and ttssue analysis. 25 ~1 of the sample extract or solutton were placed on the tantalum rtbbon. For very low cadmmm levels. more sample. up to IO0 ~1, can be used.
RESULTS
AND
DISCUSSION
Contartrihatiort During the early stages of this work, severe problems were encountered with sample contamination when the flameless atomic-absorption technique was employed, because of the extreme sensitivity of atomic-absorption for cadmium (4 pg). Glass test-tubes were found unsatisfactory despite repeated soakings in acid and 5% Triton X-100 solution. Plastic tubes were far more satisfactory but still required cleaning. Soaking in 8M nitric acid overnight was found inadequate. However, excellent results were obtained when the tubes were soaked overnight in 5”/, w/v Triton X-100 solution. The tubes used were polypropylene with snap caps, which could be capped lightly during heating, thus preventing any loss. 16
Determlnotron
of
Cd in urine
(Direct osprrotionl
ta E
a
n
Bockground - correction
n
Non- bockground - correctron Fig. 1. Determinatton
mode mode
of Cd in urine.
Reagent-grade nitric acid was found to have a cadmium content of 5-10 pg/ml and could not be used, but Baker “Ultrex” nitric acid contained less than lpg/ml and was very satisfactory. The APDC. MIBK and other reagents used for the determination of cadmium in blood were found to be virtually free from cadmium contamination. Under the conditions mentioned above. very low blanks were observed in all cases. The determination of cadmium in urine has suffered considerable difficulty in the past from interferences by alkali metal salts in the sample. This has led to erroneously high values for cadmium in urine. 20-50 pg/15 Because of the high salt content, most urine cadmium analyses are performed by a solvent extraction technique. Figure 1 shows results for determination ofcadmium in urine by direct aspiration in the non-background-correction mode and the automatic background-correction mode. A significant amount of background signal is evident. This also shows the utility of the background-correction mode.
748
PAUL A. ULLUCCIand
JAE
Y. HWANG
Thus, use of the automatic background-correction mode coupled with high scale-expansion (100 X) and signal integration makes possible the direct determination of cadmium in urine. The cadmium value which we have obtained, 4 &l, is consistent with normal data previously published, Table 2. More data’concerning normal levels of cadmium in the body may be found in reference 5. Table 2. Normal
values of cadmium materials
in biological
Sample
Average
Range
Urine,14 m/l00 ml Blood,14 /q/I. Liver,’ ppm Kidney,’ ppm
0.85 1.6 2.03 11.2
0.3-50 05-l 1.0 1.19-3.71 21-220
Blood analysis
The extraction procedure presented here for the blood samples is merely an adaptation of a method used for the determination of lead in blood, reported earlier.‘2V’3 Results obtained from four normal blood samples by using the method described are given in Table 3. These results yielded a cadmium result of O-3 pg/lOO ml. The results presented for the normal blood samples are consistent with those previously published, Table 3. Lead can also be determined in the same extract. Table 3. Cadmium in whole blood (~/lo0 Sample Sample Sample Sample Sample Sample Sample
A* B B + 1.0 pg Cd/l00 ml C C + 1.0 pegCd/100 ml D D + 1.0 pegCd/100 ml
ml)
0.3 0.4 1.6 0.2 1.3 0.4 1.3
* Results for Samp.le A were verified by standard additions.
Hair and nail analysis
Analytical results obtained from the determination of cadmium in hair and nails are given in Table 4. In all cases, duplicate determinations gave good agreement. Normal levels of cadmium in hair are not well documented, since variations occur with sex, age, sampling site, colour of hair, and especially external contamination. The value of hair analysis as a measure of cadmium intoxication is not understood and is disputed.’ A IOmg sample of hair is used since at least this amount of hair is necessary for the sample to be representative. Ca, Mg, Na and K can be determined by aspiration in this same sample as well as Cu, Cr, Mn, Zn, Fe and Pb by flameless atomic-absorption. Tissue analysis
The most important analyses conducted were those performed on the tissue samples. The goal here was to establish whether or not biopsy tissue analysis could be used as a means of determining toxic exposure to cadmium. Autopsy samples of kidney and liver organs were sampled in triplicate from different portions of the organ. At the same time
749
Cadrmum m blological materials Table 4. Cadmium in hau and nails Sample
Cd,
Hair No. 1 Hair No. 2 Hair No. 3 Hair No. 4 Nails No. 9
Sample
ppm
4.1 3.7 1.0 0.8 1.7 2.5 2.4 2.3 25
Cd. ppm
Hair No. 5
3.2 2.4 3.4 4.5 4.5 4.9 I.7 0.32
Hair No. 6 Hair No. 7 Hair No. 8 Nails No. 10
a 2-g sample was taken from the organ for conventional flame-aspiration atomic-absorption analysis. The results obtained are summarized in Table 5. It is important to notice the large spread in the three different analyses of the same organ. To ascertain whether the range of values obtained was due to variation in cadmium concentration at different locations in the organ, or due to poor reproducibility of the method, NBS SRM No. 1157, Table 5. Cadmium m kidney and
liver autopsy samples. ppm
Cadmium Sample
Weight of sample, mg
A (Kidney)
9.8 5.2 10.3 18.4 18.2 13.8 21.2 11.0 12.5 12.7 11.5 8.5
B (Kidney)
C (Liver)
D (Kidney)
Flameless 127 150 167 42 64 92 2.2 4.8 2.8 2.1 4.4 5.3
Flame
150
69
3.0
5.0
bovine liver. was analysed by the method presented. The results of the triplicate cadmium determinations are shown in Table 6. The accuracy and precision of the analysis were found to be excellent and thus it is obvious that the variation in cadmium concentrations observed is attributable to the heterogeneous distribution of cadmium in the organ. Although a significant variation in cadmium concentration at different organ locations is Table 6. Accuracy and precision of method. (NBS SRM 1157 Bovine Liver) Present method. ppm* 0.27 f 0.02 0.27 + 0.02 0.25 * 0.04
NBS data.
ppm
0.27 f 0.04
* Results based on 50-mg sample and aqueous standards Precision data based on IO readmgs.
750
PAUL A. ULLUCCIand JAE Y. HWANG
apparent, this does not rule out the validity of the method as a diagnostic tool, since in the case of individuals suffering from cadmium poisoning a considerably higher than normal organ cadmium level is observed. Acknowledgement-The authors would like to express their appreciation to Dr. George Lewis and his colleagues at the Boston V. A. Hospital for providing the autopsy samples used in this work.
REFERENCES 1. 2. 3. 4. 5.
6. 7. 8.
9. 10. 11. 12.
13. 14.
F. C. Christensen and E. C. Olsen, Archives of Industrial Health, 1957, 16,8. M. J. H. Nadi, D. Stone and H. Jeck, Lancer, 1969,2, 1329. G. M. Fischer and G. S. Think, Arch. Enoiron. Health, 1971,23, 107. J. M. Morgan, ibid., 1972 24, 364. L. Freberg, M. Piscator and G. Nordberg Cadmium in the Environment. Chemical Rubber Company, Clevelan& 1971. P. Pulido, K. Fuwa and B. L. Vallee, Anal. Biochem., 1966,14, 393. E. Berman, At. Abs. Newsletter, 1967, 6, 57. A. S. Curry and A. R. Knott, Clin. Chim. Acta, 1970.30, 115. M. M. Joselow and J. D. Bogden, At. Abs. Newsletter, 1972 11, 127. J. Y. Hwang, C. J. Mokeler and P. A. Ullucci, Anal. Chem., 1972,44,2018. J. Y. Hwang, P. A. Ullucci and C. J. Mokeler, ibid., 1973, 45, 795. R. 0. Farrelly and J. Pybug Clin. Chem., 1969, 15, 566. J. Y. Hwang, P. A. Ullucci, S. B. Smith, Jr. and A. L. Malenfant, Anal. Chem., 1971,43, 1319. D. H. K. Lee, Ed., Metallic Contaminants and Human Health, p. 236. Academic Press, New York. 1972.
ZusuaannfLJsune-Eine Anzahl biologischer Proben wie Blut, Urin, Haare, N&gel, Leber und Nieren wurden auf ihren Cadmium-gehalt analysiert. Zu der Analyse wurden das flammenlos Atomabsorptionsverfahren mit Tantalband und das iibliche Verfahren mit Ansaugen der Probe in die Flamme verwendet.
R&&-On a analyd une varittk d’tchantillons biologiques tels que sang, urine, cheveux, ongles, foie et reins pour le cadmium. On a employ& les techniques d’absorption atomique sans flamme au ruban de tantale et a aspiration de flamme ordinalre.