Report Claude Veillon U.S. Department of Agriculture Vitamin and Mineral Nutrition Laboratory Beltsville, Md. 20705
Trace E l e m e n t Analysis of Biological S a m p l e s In the late 1960s and 1970s, atomic absorption spectrometry (AAS) underwent explosive commercial development and acceptance. It seemed as if everyone, in every field, was discovering this technique and getting in on the action. One of its originators, Sir Alan Walsh of the CSIRO in Australia, once showed a plot of the exponential rise in the number of instruments vs. years. Extrapolating this curve, and assuming that each instrument occupied an area of 1 m2, it was obvious that in a few more years atomic absorption spectrometers would cover the entire land mass of the earth! Most of the interest during this period revolved around instruments using chemical flames for sample atomization, and determinations were mostly in the parts-per-million (ppm, or Mg/g) range. For most elements and samples, these systems are generally quite specific and free of interferences, and in this concentration range prevention of sample contamination is manageable. Users in the biological sciences and medical and clinical areas really took to the technique, and interest in the biological role of trace elements soared. For many samples, the matrix was a bit messy, what with proteins, salts, viscosity, etc., to contend with, but once these problems were identified solutions usually followed. Much interest was in the "essential" trace elements, such as iron, zinc, and copper, present at parts-per-million levels in many biological samples, and in "toxic" elements, such as lead and cadmium. It soon became evident that some elements, such as zinc, are ubiquitous, and present in things like glass, rubber stoppers, acids and anticoagulants. So a good deal of bad data crept into the literature, as well as some erroneous conclusions, but the situation is better today and improving. Then along came the graphite furnace atomizer, and opportunities to make mistakes really increased, ri0003-2700/86/0358-851A$01.50/0 © 1986 American Chemical Society
Problems and Precautions valed only by the advent of computers. Very early in the development of AAS, L'vov in Russia demonstrated the use of a resistively heated graphite tube as an atomizer for atomic absorption. It was an extremely successful device from a performance standpoint, with analytical sensitivities for many elements about 3 orders of magnitude better than chemical flame atomizers and few interferences. The design was not very attractive to instrument manufacturers, mostly because of size and convenience considerations. A furnace design similar to L'vov's was championed for many years by Woodruff at Montana State University and was even offered commercially. But despite its impressive performance and advantages, it was never adopted by atomic absorption instrument manufacturers, and there weren't enough homemade instrument builders to ensure its success. Numerous electrothermal atomizers came and went commercially during these years of explosive growth, such as graphite tubes, rods and cups, tantalum devices, etc., all offering compact size and convenience. The devices generally retained the extraordinary sen-
sitivity increase over chemical flames of the L'vov furnace, but posed extraordinary problems with interferences, particularly in the case of biological samples, which usually have a substantial matrix compared with the analyte. Newer designs with improved features and materials have helped a great deal, but the overall performance level of the original L'vov and Woodruff devices has still not been reached. In the biological, clinical, and nutrition areas, these graphite furnace systems were widely accepted, primarily because of the increased sensitivity they offered. Many of the trace elements of current biological interest are present in samples at levels well below those measurable by flame atomic absorption. The elements vanadium, chromium, molybdenum, manganese, cobalt, nickel, and aluminum are frequently present at concentration levels in the parts-per-billion (ppb, or ng/g) range and below. For example, in the biological fluids serum, plasma, and urine, normal levels of chromium are now accepted to be in the 0.1 ng/g region. That's one part in 10 billion. To put this in perspective, it is equivalent to a single second in 317 years! Yet, with modern instrumentation, contamination control bordering on fanatical, and sufficient attention to detail, it is possible to measure chromium directly in some samples at the 0.1-ppb level. At these very low levels, there are perhaps only three analytical methods with sufficient sensitivity for the determination: neutron activation analysis, mass spectrometry, and graphite furnace AAS. The first two are not widely available, and the third technique is the one most susceptible to matrix interference effects. So a situation evolved where extremely sensitive instrumentation became readily available in laboratories not equipped to adequately control contamination or to verify the accura-
ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986 · 851 A
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I
•5
ο
1 Absorbance units of background Figure 1. Correlation between background and apparent Cr concentration Adapted with permission from Reference 1
cy of the determinations. It was not universally appreciated that a sudden gain of 100 or 1000 in analytical sensi tivity also multiplied contamination and other problems by the same amount if one were to utilize the in creased sensitivity. This REPORT discusses some of the problems encountered and precau tions to be taken in determining trace elements in the parts-per-billion con centration range and below. Much of our experience is in determining chro mium in biological samples by graph ite furnace atomic absorption, and this article will concentrate on that determination as an example. It is per haps one of the most difficult determi nations and has an interesting history. Much of the discussion applies to oth er elements, matrices, and techniques as well. The chromium story
Chromium is an essential trace ele ment in the human diet. It is poorly absorbed, and concentrations in vari ous tissues and fluids within the body are very low. Little is known with cer tainty about its biochemical role, ex cept that it is involved in glucose me tabolism and/or the mechanism of ac tion of the pancreatic hormone insulin. A biochemical role for chromium was first pointed out by Mertz and Schwarz more than 25 years ago. Since then, a great deal of activity, analyses, and data have appeared regarding this element. Naturally, many of the ana lyses were performed by AAS, espe 852 A
cially after graphite furnaces became commercially available. Chromium excretion via urine had been proposed as a means of assessing the chromium nutritional status of in dividuals. However, reported values for urinary chromium varied by well over an order of magnitude. Between 1964 and 1970, reported values for 24-h urine collections ranged from 18 jig/day to as much as 1500 μg/day. Those reported between 1970 and 1978 ranged from approximately 3 to 10 Mg/day. A roughly parallel situ ation exists for reported concentra tions in human blood plasma or se rum, ranging from about 1-40 ng/mL prior to 1978. The urinary chromium values pre sented a dilemma from a nutritional standpoint. One might suspect that urinary chromium output could have dropped from 18 Mg/day in 1964 to 3 μg/day by 1977, reflecting a sixfold de crease in dietary chromium intake in just 13 years. However, values for di etary chromium reported in 1962 were similar to those reported more than 15 years later. Further, chromium ab sorption (i.e., fraction appearing in the urine) had been shown rather conclu sively to be about 0.5% by radiotracer experiments. So if we have 3 μg/day being excreted, and 0.5% absorption, ingestion would have to be about 600 Mg/day, or 10-fold higher than the ac tual average intake. Commercially available, state-ofthe-art atomic absorption instruments in 1978 used deuterium arc lamps as
ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986
continuum light sources for correction of the nonatomic background absorp tion, particularly with graphite fur nace atomizers. Using one of these in struments, Guthrie and co-workers (1) demonstrated conclusively that uri nary chromium could not be meas ured, because the corrector lamp in tensity was too low at the 357.9-nm chromium wavelength. A direct corre lation between background absorption and apparent chromium concentra tion was found (Figure 1). The impli cations of Figure 1 are quite serious. This means that measurements of uri nary chromium, with the best instru ments available (at the time) were merely a measure of the background produced in the furnace by the urine matrix. This cast serious doubt on the validity of all previously reported uri nary chromium values obtained by this technique. The realization that all previous data of this kind were proba bly wrong was a unique experience, at least for me. Fortunately, we had access to a nov el continuum source, échelle monochromator, wavelength-modulated atomic absorption spectrometer developed by O'Haver's group at the University of Maryland. This instrument had far greater background correction capabilities, and, lo and behold, observed urinary chromium concentrations measured with it were about a factor of 10 lower than any reported before. These also made sense in terms of the intakes and fractional absorbances mentioned earlier. However, you can't use values much lower than those ever before seen and obtained with a unique instrument to make much of a case for everyone else being wrong. So, confirmation of the value by an independent method was needed, and this was accomplished by stable isotope dilution, isotope ratio mass spectrometry. Further evidence came independently from other laboratories. At about the same time, Kayne and co-workers in Philadelphia modified an instrument similar to the one used by Guthrie, enhancing its background correction capabilities considerably. They too observed urinary chromium concentrations below 1 ng/mL. By carefully controlling furnace conditions and by adding hydrogen to the furnace gas, Routh at Varian in Australia was able to reduce background absorption from the urine matrix and also observed values below 1 ng/mL. Although this sudden 10-fold lowering of urinary chromium levels appeared to resolve the intake-absorption-excretion discrepancies of the earlier literature, it suddenly increased blank and contamination requirements by the same amount. Since 1978, considerable experience
has been gained in measuring chromium levels in urine, serum, foods, and tissues, largely as a result of improved commercial instrumentation. Improved background correction systems using Kayne's modification and other techniques such as the Zeeman effect have helped overcome these problems. Analysts must also now be aware that caution is advised and verification is imperative. Causes of analytical error The primary causes of analytical error in trace element analysis of biological samples are improper sampling, especially contamination during sample collection; contamination from, or adsorption loss to, the container; contamination, analyte loss, and uncontrolled blanks during sample preparation; and errors introduced by the analysis procedure itself. Note that three of the four involve contamination. Although element dependent to some extent, contamination is strongly concentration dependent, i.e., about 1000 times worse at nanograms-pergram levels than at micrograms-pergram levels. Sampling. Collecting a meaningful, representative sample without contaminating it is the first step in a successful analysis. Failure at this step renders all subsequent steps at best meaningless, and at worst harmful, say, in the case of medical diagnosis prior to treatment. The 1957 statement by Thiers is still valid: "Unless the complete history of any sample is known with certainty, the analyst is well advised not to spend his time analysing it." Collecting blood samples, for example, is widely accomplished with disposable stainless steel needles. Because the normal levels of elements like chromium, manganese, and nickel (major components of stainless steel) are in the nanograms-per-milliliter range and below, this practice invites serious contamination problems. For this purpose, plastic catheters or cannula are recommended, and the initial portion of the sample should be discarded or used for other measurements. We have had success using metal needles that have been siliconized, which renders the surface hydrophobic and prevents sample contamination with adventitious trace elements. Blood samples are often collected using evacuated glass containers with rubber stoppers or syringes with rubber plungers, sometimes containing an anticoagulant. These can all lead to sample contamination. I once received a call from a colleague trying to measure chromium in blood plasma. The conversation went something like this: He: "We're getting ash buildup in the furnace tubes, even with a fivefold
sample dilution." I: "A fivefold dilution would put them below your detection limit." He: "Oh, no. We get very consistent values, all about 2 ppb." I: "Next you're going to tell me you collected the samples in—(a particular evacuated tube type)." He: "How did you know?" I: "That's what we get when we use those too." It was due primarily to the anticoagulant used in the devices, at least in that batch. The established level of chromium in plasma is about an order of magnitude lower than that. Moral: Check everything. In the words of Wayne Wolf here at the U.S. Department of Agriculture, to analyze samples in the parts-per-billion and subparts-per-billion range, one has to become "usefully paranoid" about contamination. Storage. The container used to store the sample, be it the collection vessel itself or another one, is a potential source of contamination, and in some cases even analyte loss by adsorption. Generally, plastic materials such as polyethylene or polypropylene serve best. Once again, the analyst is cautioned to check everything carefully. For samples stored frozen in plastic containers for long periods, another possible source of error exists. Plastic materials are not completely impermeable to water vapor, and even frozen water has a finite vapor pressure. This can lead to a gradual moisture loss by lyophilization with time. This process can be slowed by packaging the frozen sample containers in sealed plastic bags containing a few cubes of ice, so they are in an approximately 100% relative humidity environment within the freezer. Alternatively, the samples could be freeze-dried before storage. This might be beneficial if subsequent sample preparation procedures can benefit from a dry sample. Keep in mind that biological fluids often segregate during freezing so the dry material may not be homogeneous. This is not a serious problem if the entire contents of a container are one sample or if the sample is to be reconstituted with water prior to analysis. Each of these possibilities should be carefully checked before procedures are adopted. Sample preparation. Anything done to the sample prior to analysis obviously can lead to contamination. Besides containers, other possible sources of contamination (or analyte loss) include reagents, airborne particulates, and even the analyst. In the best of worlds and with analytical techniques that are sufficiently sensitive and free of matrix interferences, one could perhaps place an aliquot of an uncontaminated sample
854 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986
collection directly into the instrument with little or no contamination. Blanks would be minimal or even unnecessary. Although there are such situations, rest assured that they are the exception rather than the rule. Urinary chromium, for example, can be determined directly by graphite furnace atomic absorption using the method of additions. Given adequately controlled sample collection, storage, containers, pipet tips, etc., the main source of contamination might be airborne. If sample manipulation is carried out in a clean room or Class100 laminar flow hood this is minimized, and routine determinations at the 0.1-0.2 ng/mL level are possible. For serum chromium determinations, the situation is far more difficult. Sample collection is not as easy, and the organic matrix needs to be destroyed by dry ashing in quartz tubes in a controlled environment, after freeze-drying, after adding a matrix modifier (e.g., Mg(N03) 2 ), after dissolution of the ash in acid, and so on. Just to make things more fun, the levels of serum chromium are slightly lower than those of urine. The good news (?) is that the uniform inorganic matrix of serum makes it unnecessary to do every sample by the method of additions. Remember, think "usefully paranoid." Another source of contamination is the analyst. Handling things with bare hands has obvious disadvantages, and skin, hair, and clothes generate particles. So you don nice vinyl gloves to prevent some of this, but not the ones powdered with talc to make them easy to put on. Then you find out that handling plastic containers with plastic gloves creates a thing called static electricity, helping to clear the air in the laboratory of airborne particles. Seriously, the analyst must take measures to protect the samples from himself or herself. In some cases, these measures are also to protect the analyst from the sample. When dealing with samples of human origin, the analyst must keep in mind the possibility of disease transmission. Contamination, by definition, leads to analysis results that are too high. Occasionally, results that are too low are obtained. Aside from analyte adsorption onto surfaces, several other causes of erroneously low results are possible. Some extraction, dissolution, or solubilization process in the procedure might be incomplete. A component of the matrix might cause a suppression of the analyte signal to a greater degree than the "standards." This is why, for example, recovery experiments and the method of additions do not verify (by themselves) the accuracy of a trace element determination in a biological matrix. These
Suppliers of biological and environmental reference materials Abbreviated name
Full name and address
BCR
Community Bureau of Reference (BCR) Commission of the European Communities 200 Rue de la Loi B-1049 Brussels, Belgium
Bl
Behring Institute P.O.Box 1140 D-3550 Marburg 1, Federal Republic of Germany
BOWEN
Dr. H.J.M. Bowen Department of Chemistry The University of Reading Whiteknights P.O. Box 224 Reading RG6 2AD, United Kingdom
IAEA
International Atomic Energy Agency Analytical Quality Control Services Laboratory Seibersdorf P.O. Box 100 A-1400 Vienna, Austria
KL
Kaulson Laboratories, Inc. 691 Bloomfield Ave. Caldwell, N.J. 07006
IRANT
Institute of Radioecology and Applied Nuclear Techniques Komenského 9 P.O. Box A-41 040 61 Kosice, Czechoslovakia and PZO Sluzba vyskumu Konévova 131 130 86 Prague 3—Zizkov, Czechoslovakia
NBS
Office of Standard Reference Materials Room B311, Chemistry Building National Bureau of Standards Gaithersburg, Md. 20899
NIES
National Institute for Environmental Studies Japan Environment Agency P.O. Yatabe Tsukuba Ibaraki 300-21, Japan
NRCC
National Research Council of Canada Division of Chemistry Ottawa K1A 0R6, Canada
NYE
Nyegaard & Co. AS Diagnostic Division Postbox 4220 Torshov N-0401 Oslo 4, Norway
SABS
South African Bureau of Standards Private Bag X191 Pretoria 0001, Republic of South Africa
are necessary-but-not-sufficient tests. Another cause of low results is loss of analyte by volatilization. This can occur during sample drying, dry ashing, wet digestion, treatment with reagents, or because of the existence of reducing (or oxidizing in some cases) conditions during sample preparation. It is more of a problem with the elements considered "volatile," such as As, Se, and Hg. The elements Zn and Cd could be lost during dry ashing at
too high a temperature, or in the presence of chloride, which could form volatile compounds of the analyte. In biological samples, the analyte might be present in a volatile organic form lost at unsuspected temperatures or a form that is somewhat refractory to complete breakdown with expected chemical treatments, leading to incomplete recoveries. Again using chromium as an example, persistent reports over the years
856 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986
have appeared suggesting that some biological forms of the element exist that could be lost during sample drying or dry ashing. Versieck and Cornells (2) reviewed this literature and concluded that this argument cannot be sustained. We have conducted numerous experiments with animal fluids and tissues endogenously radiolabeled with 51Cr in checking out various sample preparation and analysis procedures. No significant chromium losses have ever been observed, including dry ashing temperatures up to 450 °C and furnace charring temperatures of 1200 °C. All other causes of analytical error in the determination of chromium would produce high results. This is consistent with the pattern evident in the literature on this determination. Analysis. A number of analytical techniques are suitable for determining elements in biological samples. For the major elements, i.e., elements normally present in substantial quantities, such as Na, K, Ca, and Mg, most techniques allow or require a substantial dilution of the sample. This also dilutes the sample matrix as well, although these elements usually are the matrix for the trace elements present at much lower concentrations. Techniques most popular for these elements include flame atomic emission spectrometry, flame AAS, ion-specific electrodes, and colorimetry. For the trace elements present in the partsper-million concentration range, e.g., Fe, Cu, and Zn, a wide variety of the techniques are used, including atomic emission, absorption, and fluorescence; voltammetry; and neutron activation. Probably the most widely used technique is flame AAS. For the ultratrace elements, those with concentrations in the parts-per-billion region and below, the number of suitable techniques drops rapidly, because of the analytical sensitivity required. Some determinations, generally those somewhat above the 1-ng/g level, have been reported using inductively coupled plasmas (ICPs), both by atomic emission and by atomic fluorescence, and by voltammetry. As stated earlier, for elemental concentrations at these levels, and especially for those in the sub-parts-per-billion range, neutron activation, mass spectrometry, and furnace atomic absorption techniques are needed, the last being by far the most accessible. Accuracy verification. Because of the ready availability of atomic absorption spectrometry, and because many users of the technique do not fully understand or appreciate the limitations of the methodology, a great deal of questionable data has appeared in the literature. It is questionable in the sense that the accuracy of
the results has not been adequately established. This problem was addressed recently by Versieck in a paper titled "Trace element analysis—A plea for accuracy" (3). In the abstract he states that: Mounting evidence suggests that much previous work on trace elements in human body fluids and tissues must have severely suffered from méthodologie deficiencies. In these days of confusion about the reliability and validity of trace element measurements, upon which far reaching decisions are made concerning health affairs, accuracy is urgently needed and indeed required if rational conclusions are ίο be reached. I agree entirely with this and feel very strongly that all analytical data pub lished by journals should be verified for accuracy. Accuracy of an analytical determi nation can be established in one of two ways. The first way would be to ana lyze the same samples (or representa tive samples if the matrix is uniform) by two or more independent methods. Because many laboratories do not have (or have access to) two indepen dent methods for the same determina tion, the second way would be to ana lyze reference materials. These are materials whose analyte content(s) has been established by two or more independent methods, and whose ma trix is as nearly identical to that of the samples as possible. In the past, the number of suitable
biological reference materials was small, and the analyte concentrations not always in the most useful range. This situation, however, has changed a great deal in the past few years. A number of organizations and laborato ries have produced and established the analyte concentrations in a variety of biological reference materials. The most complete and recent compilation of these is that of Muramatsu and Parr (4) of the International Atomic Energy Agency in Vienna, Austria. The box on p. 856 A is a list of suppli ers of these biological materials, and the appendix following this article lists the elements for which informa tion is available. A complete copy of the survey can be obtained from R.M. Parr, IAEA, P.O. Box 100, A-1400 Vi enna, Austria. The use of these reference materials in verifying the accuracy of methods used to generate data on trace element content of biological samples is per haps, in the words of Versieck (3), "the only way out of the morass of confusion." There are still some gaps in available materials, particularly in materials where the analyte content is very low, but several groups are work ing to fill these gaps in the very near future. I urge all editors and reviewers, par ticularly in nonanalytical journals that publish analytical data, and especially those in the biological areas, to insist that analytical data be verified and/or the accuracy of the method for that
determination in that sample type be established. I know that this is not al ways possible, due to lack of an appro priate reference material or access to an independent method. But if this is the case, do we really need these data?
References (1) Guthrie, B. E.; Wolf, W. R.; Veillon, C. Anal. Chem. 1978,50,1900. (2) Versieck, J.; Cornells, R.; Anal. Chim. Acta 1980,116, 217. (3) Versieck, J. Trace Elem. Med. 1984,1, 2. (4) Muramatsu, Y.; Parr, R. M. IAEA/RL/ 128, December 1985.
Claude Veillon is a research chemist in the Vitamin and Mineral Nutri tion Laboratory, one of five laborato ries comprising the Beltsville Human Nutrition Research Center of the U.S. Department of Agriculture. He re ceived his undergraduate training in chemistry at the University of South western Louisiana and graduate training in analytical chemistry (Ph.D. 1965) from the University of Florida, specializing in atomic spec troscopy. In the early 1970s, his re search interests turned toward the role of trace metals in biological sys tems. His current interests are in de veloping valid methods for essential trace elements in biological samples, application of enriched stable iso topes in metabolic tracer studies in humans, and preparation of biologi cal reference materials.
Appendix. Overview of biotogical and environmental reference materials and elements quoted3 Supplier
BCR
Material
Name or code No. (Supplier)
Code No. (this report)
Unit weight or volume
Cost
Quoted elements
Biological materials Aquatic plant
CRM-060
BCR-CRM-060
25 g
$25
Aquatic plant
CRM-061
BCR-CRM-061
25 g
$25
Olive leaves
CRM-062
BCR-CRM-062
25 g
$25
Skim milk powder
CRM-063
BCR-CRM-063
30 g
$45
Skim milk powder (lower level spiked) Skim milk powder (higher level spiked) Blood Blood Blood Single-cell protein
CRM-150
BCR-CRM-150
30 g
$30
AlCaCdCI Cu Fe Hg Κ Mg Μη Ν Na Ρ Pb S Si Ti Zn Al Ca CdCl Ci/Fe HgK Mg MnH Na Ρ Pb S Si Ti Zn Al Ca CdCI Cu Fe Hg Κ Mg Μη Ν Na Ρ Pb S Si Ti Zn CaCdCICo CuFeHgKMgMn NWaNi Ρ Pb Se TI Zn Cd Co Cu Fe Hg 1 Mn Ni Pb Se TI Zn
CRM-151
BCR-CRM-151
30 g
$30
Cd Co Cu Fe Hg 1 Mn Ni Pb Se TI Zn
CRM-194 CRM-195 CRM-196 CRM-273
BCR-CRM-194 BCR-CRM-195 BCR-CRM-196 BCR-CRM-273
? ? ? ?
BCR-CRM-038
6g
$20
BCR-CRM-040 BCR-CRM-141
50 g 40 g
$56 $25
Environmental materials (nonbiological) Fly ash CRM-038 Coal Soil (calcareous loam)
CRM-040 CRM-141
? ? ? ?
CdPb CdPb CdPb CaFeKMgNP As Cd Co Cr Cu Fe Hg Mn Na Ni Pb Th W Zn As Cd Co Cr F Hg Mn Ni Pb TI Zn Al Ca Cd Co Cr Cu Fe Hg Κ Mg Mn Na Ni Ρ Pb Se Si Ti Zn continued
8
If the element symbol is italicized, a certified or recommended value is available; if not italicized, only an information value is available.
858 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986
Appendix, continued Supplier
BCR
Bl
Material
Code No. (this report)
Environmental materials (nonbioiogical) cont. Soil (light sandy) CRM-142 BCR-CRM-142
Unit weight or volume
Cost
40 g
$25
Quoted elements
Al Ca Cd Co Cr Cu Fe Hg Κ Mg Mn Na Ni Ρ Pb Se Si Ti Zn Al Ca Cd Co Cr Cu Fe Hg Κ Mg Mn Na Ni Ρ Pb Se Si Ti Zn Al As Ca Cd Co Cr Cu Fe Hg Κ Mg Mn Na/V/PPbSeSiTiZn Al Ca Cd Co Cr CoFe HgKMg Mn Na M Ρ Po Se Si TiZn Al Ca Cd Co Cr CuFe HgKMg MnNa NI Ρ Pb Se Si Ti Zn Al As Ca Cd Co Cr Cu Fe Hg Κ Mg Mn Na NI PPbSSb Se Si Ti TI Zn AsCCdCIHHgMnNPbSeVZn AsCCdCIHHgMnNPbSeV Zn AsCCdCIHHgMnNPbSe VZn
Soil (amended sewage sludge) Sewage sludge (domestic origin) Sewage sludge
CRM-143
BCR-CRM-143
40 g
$25
CRM-144
BCR-CRM-144
40 g
$25
CRM-145
BCR-CRM-145
40 g
$25
Sewage sludge (industrial origin) City waste Incineration ash Gas coal Coking coal Steam coal
CRM-146
BCR-CRM-146
40 g
$25
CRM-176
BCR-CRM-176
30 g
$25
CRM-180 CRM-181 CRM-182
BCR-CRM-180 BCR-CRM-181 BCR-CRM-182
? ? ?
Control blood for metals 1 (OSSD) Control blood for metals 2 (OSSE) Lanonorm metals 1 (OSSA) Lanonorm metals 2 (OSSB) Lanonorm metals 3 (OSSC)
BI-CBM-1
4 X 5mL
$22
CdCrHgPb
BI-CBM-2
4X5mL
$22
CdHgPb
BI-CUM-1
12 X 50 mL $74
As Cd Co Cr Cu F Hg Ni Pb
BI-CUM-2
12 X 50 mL $74
As Cd Co Cr Cu F Hg Ni Pb TI
BI-CUM-3
1 2 X 5 0 m L $74
As Cd Co Cr Cu F Hg Ni Pb TI
Kale
BOWEN's Kale
100 g
$15
Ag Al AsAuBBaBrCCaCd Ce Cl Co Cr Cs Cu Eu F Fe Ga H Hf Hg I In Κ La Li Lu Mg Mn Mo Ν Na Ni Ο Ρ PbRb Ru S Sb Se Se SI Sm Sn Sr Th U V\N Zn
Biological materials Milk powder
A-11
IAEA-A-11
25 g
$40
Animal blood
A-13
IAEA-A-13
25 g
$80
Animal muscle
H-4
IAEA-H-4
2 X 10 g
$80
Animal bone Horse kidney
H-5 H-8
IAEA-H-5 IAEA-H-8
2 X 15 g 30 g
$40 $40
Copepod
MA-A-1(TM)
IAEA-MA-A-1
30 g
$40
Fish flesh
MA-A-2(TM)
IAEA-MA-A-2
30 g
$40
Mussel tissue
MA-M-2(TM)
IAEA-MA-M-2
25 g
$40
Rye flour
V-8
IAEA-V-8
50 g
$40
Cotton cellulose
V-9
IAEA-V-9
25 g
$80
Hay powder
V-10
IAEA-V-10
50 g
$80
Al As Au Β Ba Br Ca Cd CI Co Cr Cs Cu F Fe Hg Ι Κ Li Mg Mn Mo Na Ni Ρ Pb Rb Sb Se Si Sn Sr V Zn Br Ca Cu Fe KMg Na Ni Ρ Pb Ri» S Se Zn Al As Br Ca Ce Cl Co Cr Cs Cu Fe Hg Κ Mg Mn Mo Na Rb S Se V W Zn Ba BrCa Cl Fe Κ MgNa PPb SrZn Br Ca Cd Cl Co Cs Cu Fe Hg Κ Mg Mn Mo NaPRbS Se Sr Zn Ag As Cd Co Cr Cu Fe Hg Mn Ni Pb Sb SeZn Ag As Cd Co Cr Cu Fe Hg Mn Ni Pb Sb SeZn Ag As Au Br Ca Cd Cl Co Cr Cu Fe Hg Mg Mn Na Pb Rb Sb Se Se Sr Zn Al Au Ba Br Ca Cd C/Co Cs Cu Fe Κ Mg MnMoHaPRbSSbZn Al Ba Br Ca Cd Cl Cr Cu Fe Ga Hf Hg Li Mg Mn Mo Na Ni Pb S Se Se Sm Sn SrThU V Al Ba Br Ca Cd Co Cr Cs CuEuFeHgK La Mg Mn Mo Na Ni Ρ Pb Rb Sb Se Se SrZn
Biological materials Blood
Blood
Urine
Urine
Urine
BOWEN Biological materials Kale
IAEA
Name or code No. (Supplier)
?
? ?
continued^* 860 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986
Appendix, continued Name or code No. (Supplier)
Code No. (this report)
Environmental materials (nonbiological) Air filter Air-3/1
IAEA-Air-3/1
Marine sediment
SD-N-1/2(TM)
IAEA-SD-N-1/2
Lake sediment
SL-1
IAEA-SL-1
25 g
$80
Soil
SOIL-7
IAEA-SOIL-7
25 g
$80
Fresh water
W-4
IAEA-W-4
Fresh water
W-5
IAEA-W-5
Supplier
IAEA
IRANT
KL
Material
Unit weight or volume
Six filters (+ six blanks) 25 g
Cost
Quoted elements
$80
As Au Ba Cd Co Cr Cu Fe Hg Mn Mo Ni PbSeUVZn
$80
Ag AI As Au Ba Be Br Ca Cd Ce CI Co Cr Cs Cu Dy Eu Fe Hf Hg I K La Li Lu Mg Mn Mo Na Nd Ni Ρ Pb Rb Sb Sc Se Si Sm Sr Ta Tb TnTi U l / W Y Y b Zn Zr As Ba Br Ca Cd Ce Co Cr Cs Cu Dy Eu Fe Ga Ge Hf Hg Κ La Li Lu Mg Mn Mo Na Nd Ni Pb Ftb S Sb Se Se Sm Sr Ta Tb ThTiUVVJY YbZnZr AI As Ba Br Ca Cd Ce Co Cr Cs Cu Dy EuF Fe Ga HfHg HoK La Li Lu Mg Mn Mo Na Nb AW Ni Ρ Pb Rb Sb Sc Se Si Sm Sr Ta TbThTiUVY Yb Zn Zr AI As Β Ba Be Ca Cd Co Cr Cu Fe Hg Κ Mg Mn Mo Na Ni Pb Se Sr U V Zn
Concentrates $80 in quartz ampule Concentrates $40 In plastic bottle
(Same as W-4)
Environmental materials (nonbiological) Coal fly ash ECH
IRANT-ECH
50 g
$80
Coal fly ash
ENO
IRANT-ENO
50 g
$80
Coal fly ash
EOP
IRANT-EOP
50 g
$80
Contox No. 0100 (High) Contox No. 0100 (Low) Contox No. 0100 (Medium) Contox No. 0110 (High) Contox (No. 0110 (Low) Contox No. 0110 (Medium) Contox No. 0140 (I) Contox No. 0140(11) Contox No. 0141 (I) Contox No. 0141 (II) Contox No. 0146 (I) Contox No. 0146 (II)
KL-100-H
4X5mL
$40
Pb
KL-100-L
4X5mL
$30
Pb
KL-100-M
4X5mL
$30
Pb
KL-110-H
4 X 5mL
$40
Pb
KL-110-L
4X5mL
$30
Pb
KL-110-M
4X5mL
$40
Pb
KL-140-I
4X5mL
$50
AsCdHg
KL-140-II
4 X 5mL
$50
AsCdHg
KL-141-1
4 X 5mL
$50
AsCdHg
KL-141-II
4X5mL
$50
AsCdHg
KL-146-I
4X5mL
$50
Cu Fe Zn
KL-146-II
4 X 5mL
$50
Cu Fe Zn
Biological materials Blood (lead control) Blood (lead control) Blood (lead control) Urine (lead control) Urine (lead control) Urine (lead control) Urine (heavy-metal control) Urine (heavy-metal control) Blood (heavy-metal control) Blood (heavy-metal control) Serum (trace metal control) Serum (trace metal control)
AI As Ba Be Ca Cd Ce Co Cr Cs Cu Eu Fe Ga Hf Κ La Lu Mg Mn Na Ni Pb Rb Sb Se Si Sm Sr Ta Tb Th Ti U V Yb ZnZr AI As Ba Ca Ce Co Cr Cs Cu Eu Fe Ga Hf KLaLuMg Mn Na Ni Pb Rb Sb Sc Si Sm Sr Ta Th Ti UVYbZn Zr AI As Ba Be Ca Cd Ce Co Cr Cs Cu Eu FeGaHfK La Lu Mg Mn Na Ni Pb Rb Sb Se Si Sm Sr Ta Tb Th Ti U V Yb ZnZr
continued
862 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986
—*•
Appendix, continued Supplier NBS
Material
Name or code No. (Supplier)
Unit weight or volume
Cost
Quoted elements
Biological materials Albacore tuna
RM-50
NBS-RM-50
2X35 g
$81
As Hg Κ Μη Na Pb Se Zn
Bovine serum
RM-8419
NBS-RM-8419
3 X 4mL
$52
AI Ca Co Cr Cu Fe Κ Mg Mn Mo Na Ni
Milk powder (nonfat)
SRM-1549
NBS-SRM1549
100 g
$138
S e V Zn Ag AI AI As Br Ca Cd CI Co Cr Cu F Fe
Oyster tissue
SRM-1566
NBS-SRM1566
30 g
$89
Ag As Br Ca Cd CI Co Cr CuF FeHg\K Mg Mn Mo Na Ni Ρ Pb Rb S Se Sr Th Tl U V Zn
Wheat flour
SRM-1567
80 g
$105
As Br Ca Cd Cu Fe Hg Κ Μη Mo Na Ni Rb Se Te Zn
Rice flour
SRM-1568
NBS-SRM1567 NBS-SRM1568
80 g
$105
As Br Ca Cd Co Cu Fe Hg Κ Μη Mo Na Ni Pb Rb Se Te
Brewers yeast
SRM-1569
50 g
$88
Cr
Citrus leaves
SRM-1572
NBS-SRM1569 NBS-SRM1572
70 g
$101
Tomato leaves
SRM-1573
70 g
$102
Pine needles
SRM-1575
NBS-SRM1573 NBS-SRM1575
AI As Ba Br Ca Cd Ce CI Co Cr Cs Cu Eu Fe Hg 1 Κ La Mg Mn MoN NaNiP Pb Rb S Sb Se Se Sm Sn S r T e Tl U Zn AI As Β Br Ca Cd Ce Co Cr Cu Eu Fe Hg
70 g
$102
Κ La Mg Μη Ν Ρ Pb Rb Sc Sr Th Tl U Zn AI As Br Ca Ce Co Cr Cr Cu Eu Fe Hg Κ La Μη Ν Ni Ρ Pb Rb Sb Sc Sr Th Tl U
Bovine liver
SRM-1577a
NBS-SRM1577a
50 g
$116
AgMAs&cCaCdCICoCuFeHgKMg
Urine (normal) (Freeze-dried)
SMR-2670
NBS-SRM2670
$184
MnMoNNaPPbRbSSbSeSrT\UZn AI As Be Ca Cd CI Cr Cu Hg Κ Mg Mn
Urine (spiked) (Freeze-dried)
SRM-2670
NBS-SRM2670
Environmental materials (nonbiologlcal) Crude oil RM-8505 Coal fly ash SRM-1633a
NIES
Code No. (this report)
HglKMg Mn Mo Na PPbRbS Si Sn Zn
2 X 20 mL
Sb Se
Na Ni Pb Pt S Se Al As Be Ca Cd CI Cr Cu Hg Κ Mg Mn Na Ni Pb Pt S Se
NBS-RM-8505 NBS-SRM1633a
275 mL 75 g
$52 $125
V Al As Ba Be Ca Cd Ce Co Cr Cs Cu Eu Fe Ga Hf Hg Κ Mg Mn Mo Na Ni Pb Rb Sb Se Se Si Sr Th Ti Tl (J V Zn As Be Br Ca Cd CI Co Cr Fe Hg Mn Mo
Fuel oil
SRM-1634a
NBS-SRM1634a
100 mL
$153
Coal (Sub-bituminous) Fuel
SRM-1635
75 g
$108
NaNiPbSSeVZn M AsCd Ce Co Cr Cu Eu Fe Ga Hf Mn Na NiPbSSb Se Se ThTi U VZn
SRM-1636a
Set (12)
$111
Pb
Water
SRM-1641b
6 X 20 mL
$126
Hg
Water
SRM-1642b
950 mL
$154
Hg
Water
SRM-1643b
NBS-SRM1635 NBS-SRM1636a NBS-SRM1641b NBS-SRM1642b NBS-SRM1643b
950 mL
$163
Ag As Β Ba Be Bi Cd Co Cr Cu Fe Mn
River sediment
SRM-1645
NBS-SRM1645
70 g
$135
AI As Ca Cd Co Cr Cu F Fe Hg Κ La Mg
Estuarine sediment
SRM-1646
NBS-SRM1646
75 g
$116
Urban particulate
SRM-1648
NBS-SRM1648
2g
$127
AI As Be Ca Cd Ce Co Cr Cs Cu Eu Fe Ge Hg Κ Li Mg Mn Mo Na NI Ρ Pb Rb S Sb Se Se Si Te Th Ti Tl V Zn Ag AI As Ba Br Cd Ce CI Co Cr Cs Cu Eu Fe Hf 1 In Κ La Mg Mn Na Ni Pb Rb S Sb Se Se Sm Th Ti U V W Zn
Biological materials Pepperbush
CRM-1
NIES-CRM-1
14 g
Free
As Ba Ca Cd Co Cr Cs Cu Fe Hg Κ Mg
Mo Ni Pb Se Sr Tl V Zn Mn Na Ni Pb S Sb Se Se Th Tl U V Zn
Mn NaNiP
PbRbSrT\
Zn
Chloreila Human hair
CRM-3
NIES-CRM-3
36 g
Free
CRM-5
NIES-CRM-5
2g
Free
Ca Cd Co Cu Fe KMgMnP Pb Sc Sr Zn AI Ba Br Ca Cd CI Co Cr Cu Fe Hg Κ Mg
Mussel
CRM-6
NIES-CRM-6
10g
Free
Ag AI As Ca Cd Co Cr Cu Fe Hg Κ Mg
Mn Na Ni Ρ Pb Rb Sb Se Se Sr Ti Zn Mn Na Ni Ρ Pb Se Sr Zn Environmental materials (nonbiologlcal) CRM-2 Pond sediment
NIES-CRM-2
20 g
Free
AI As Br Ca Cd Co Cr Cu Fe Hg Κ La Mn Na Ni Ρ Pb Rb Sb Sc Si Sr Ti V Zn continued—-
864 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986
Appendix, continued Supplier
NRCC
NYE
SABS
Name or code No. (Supplier)
Code No. (this report)
Unit weight or volume
Cost
NRCC-TORT-1
30 g
$62
As Ca Cd CI Co Cr Cu Fe Hg Κ Mg Mn Mo Na NiPPb S Se Sr V Zn
Environmental materials (nonbiological) Marine sediment BCSS-1
NRCC-BCSS-1
80 g
$87
Seawater Marine sediment
CASS-1 MESS-1
NRCC-CASS-1 NRCC-MESS-1
2L 80 g
$109 $87
Seawater
NASS-1
NRCC-NASS-1
2L
$109
AlAsBeCCa CdCICo Cr Cu Fe Hg Κ Mg Mn Na Ni Ρ Pb S Sb Si Ti V Zn As Cd Co Cr Cu Fe Mn Ni Pb Zn AI As Be C Ca Cd CI Co Cr Cu Fe Hg Κ Mg Mn Na Ni Ρ Pb S Sb Si Ti V Zn As Cd Co Cr Cu Fe Mn Mo Ni Pb Zn
Biological materials Serum Urine Serum
SERONORM(105) SERONORM(108) SERONORM(164)
NYE-105 NYE-108 NYE-164
6X3mL 6 Χ 10 mL 10 Χ 5 mL
? ? ?
Se Se CaCICuFeKMgNNaPZn
SABS-SARM18
120 g
?
ΑΙ Β Ba Be Br Ca Ce Co Or Cs Cu Eu Fe Ga Ge Hf Hg Κ La Li Mg Mn Mo Na Nb Ni PPbRbS Sb Se Si Sm Sn Sr Ta Tb Th Ti U VWI Y Zn Zr AlAsBBa Be Br Ca Ce CI Co Cr Cs Cu Eu Fe Ga Ge Hf Hg Κ La Li Mg Mn Mo Na Nb Ni PPbRbS Sb Se Se Si Sm Sn Sr Ta Tb ThTiUVWY Yb Zn Zr AI As Β Ba Be Br Ca Ce Co Cr Cs Cu Eu Fe GaHfHgK La Li Mg Mn Na Nb M PPbRbS Sb Se Se Si Sm Sn Sr Ta Tb Th TiUVW YYbZnZr
Material
Biological materials Lobster hepatopancreas
TORT-1
Environmental materials (nonbiological) Coal (Witbank) SARM-18
Coal (O.F.S)
SARM-19
SABS-SARM19
120 g
?
Coal (Sasolburg)
SARM-20
SABS-SARM20
120 g
?
Quoted elements
Wi union σικεη
Stopped Flow Rapid Sean Spectrophotometer • Minimum dead time — 500 Msec >16 spectra measured every 1 msec sequentially •Simple and robust mixing system without syringe • Fluorescence, T-jump and flash accessories. CIRCLE 2 ON READER SERVICE CARD 866 A · ANALYTICAL CHEMISTRY, VOL. 58, NO. 8, JULY 1986
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