Lead, determination blood

Amongst other devices used to produce the required atoms in the vapour state are the Delves cup which enables the determination of lead in blood samples the sample is placed in a small nickel cup which is inserted directly into an acetylene-air flame. The tantalum boat is a similar device to the Delves cup in this case the sample is placed into a small tantalum dish which is then inserted into an acetylene-air flame. The use of these devices, especially for small sample volumes, has now been largely superseded by the graphite furnace. 

Fernandez, F. J. "Micromethod for Lead Determination In Whole Blood by Atomic Absorption, With Use of the Graphite Furnace". Clin. Chem. (1975), 21, 558-561. 

Flameless Atomic Absorption Determination of Lead In Blood . Anal. Chem. (1973), 795-798. 

Norval, E. and Butler, L R P "The Determination of Lead In Blood by Atomic Absorption with the High-Temperature Graphite Tube". Anal. Chlm. Acta (1972), 47-56. 

Blood Chemistry Data. All blood specimens were obtained by venipuncture. The erythrocyte protoporphyrin (EP) was measured by the extraction method. Blood lead determinations were done In quadruplicate and are presented as an arithmetic mean of the four replicates. 

Anodic stripping voltammetry (ASV) has been used extensively for the determination of heavy metals in samples of biological origin, such as lead in blood. ASV has the lowest detection limit of the commonly used electroanalytical techniques. Analyte concentrations as low as 10 M have been determined. Figure 16 illustrates ASV for the determination of Pb at a mercury electrode. The technique consists of two steps. The potential of the electrode is first held at a negative value for several minutes to concentrate some of the Pb " from the solution into the mercury electrode as Pb. The electrode process is... 

The determination of lead in blood is the most widespread clinical use of ASV The technique is attractive because it is rapid, simple and reproducible A recent advance is to couple ASV to flow injection analysis in order to automate the process so that smaller samples and shorter analysis time can be achieved Lead is also routinely determined in bonemeal meant for human consumption by ASV Both lead and cadmium are determined in agricultural crops by ASV... 

There are two main types of proficiency testing scheme. First, there are those set up to assess the competence of a group of laboratories to undertake a very specific analysis, e.g. lead in blood or the number of asbestos fibres in air collected on membrane filters. Secondly, there are those schemes used to evaluate the performance of laboratories across a certain sector for a particular type of analysis. Because of the wide range of possible analyte/matrix combinations it is not practicable to assess the performance of laboratories when analysing all the possible sample types. Instead, a representative cross-section of analyses is chosen (e.g. determination of different pesticide residues in a range of foodstuffs or the determination of trace levels of metals in water samples). 

A GC-MS method for determining the isotope composition of lead in blood and urine samples is based on preparation of Pb(CgH4F-p)4 using the corresponding Grignard reagent108. 

Lead-exposed employees in the United States111, for example, must be removed from work if the average of their last three blood lead determinations is at or above 0.50 pgPbg-1 whole blood and if the airborne lead level is at or above 30 Agm-3. 

Pain, D.J., C. Metayer, and J.C. Amiard. 1993b. Lead determination in avian blood application to a study of lead contamination in raptors from France. Int. Jour. Environ. Anal. Chem. 53 29-35. 

There is a great deal of interest in the determination of lead, particularly micromethods applicable to the analysis blood lead in children. Consequently, reports continue to appear on the atomic absorption determination of lead in blood and urine. Ninety percent of blood lead is found in the erythrocytes and, therefore, whole blood is analyzed rather than serum or plasma. Berman etal. 134) have described a procedure for determining normal lead levels in which only 250 fd of blood are taken. The blood is deproteinized with 1 ml of 10 % trichloroacetic acid and then the lead is extracted with APDC into 1 ml of MIBK, at pH 3.5. 

Determination of lead in blood by Delves-cup AAS. Both weighted and unweighted curves of best fit are shown. 

To deal with this problem the EPA invested in the development and validation of a pharmacokinetic model that is capable of relating intake of lead to blood level. The model also allows the risk assessor to develop blood level estimates that integrate all sources of exposure. Using this model, it becomes possible to determine whether a specific source, such as our suspect water supply, is leading to exposures in excess of the target for all sources combined (this assumes that other sources do not contain levels of lead greater than normal, background... 

An analyte transport efficiency of nearly 100% has been obtained with an interface for flame atomic absorption spectrometry (FAAS) [3]. It has been used for the determination of lead in blood [5] and for coupHng with a high-performance Hquid chromatograph (HPLC) [6]. 

In 1970, Delves15 described the use of 10 mm diameter nickel metal foil micro-crucibles for the atomization of lead in blood samples, after a partial pre-oxidation with hydrogen peroxide at 140 °C. The technique, which became widely known as the Delves Cup Technique , was extensively used for more than a decade in many laboratories around the world, and was also applied to environmental analyses such as the determination of lead in water. A flame-heated nickel tube was again used to overcome the reproducibility problems otherwise caused by the variability in the construction of individual disposable cups. 

Numerous procedures for die determination of lead in blood by atomic absorption spectrophotometry have been reported. The first mediod described here uses a nickel cup to contain the sample, a conventional air-acetylene flame atomiser, and a... 

Willis (W12, W14) reported the determination of lead in urine. Lead was chelated with ammonium pyrrolidine dithiocarbamate and extracted into methyl-n-amyl ketone. Urine samples of 50 ml had to be extracted into 1.5 ml of the solvent to obtain sufficient concentration of the metal. Differences in the efficiency of extraction from water and urine at various pH values were noted. The availability of a reliable and simple method such as the one described will be welcomed by medical laboratories, but unfortunately the limited sensitivity requiring large original samples makes the method less applicable for the determination of lead in blood. 

D12. Delves, H. T., A micro-sampling method for the rapid determination of lead in blood by atomic absorption spectrophotometry. Analyst London) 95, 431-438 (1970). 

Feldman BJ, Oserioh JD, Hata BH, D Alessandro A. Determination of lead in blood by square wave anodic stripping voltammetry at a carbon disk ultramicroelectrode. Anal Chem 1994 66 1983-7. 

The first requirement can be easily fulfilled by the preconcentration of the analyte before the analysis. Preconcentration has been applied to sample preparation for flame atomic absorption (25) and, more recently, for ICP (79,80) spectroscopy. However, preconcentration is not completely satisfactory, because of the increased analysis time (which may be critical in clinical analysis) and the increased chance of contamination or sample loss. Most important, however, a larger initial sample size is necessary. The apparent solution is a more sensitive technique. Table 2 lists concentrations of various metals in whole blood or serum (81,82) in comparison to limits of detection for the various atomic spectroscopy techniques. In many cases, especially for the toxic heavy metals, only flameless atomic absorption using a graphite furnace can provide the necessary sensitivity and accommodate a sample of only a few microliters (Table 1). The determination of therapeutic gold in urine and serum (83,84), chromium in serum (85), skin (86) and liver (87), copper in semen (88), arsenic in urine (89), manganese in animal tissues (90), and lead in blood (91) are but a few examples in analyses which have utilized the flameless atomic absorption technique. 

In-line filtration without a filtering element is also feasible. To this end, a three-dimensional reactor [299], also called a knitted or knotted reactor (see 6.2.3.4), can be used, as emphasised in the landmark article reporting the flow injection determination of lead in blood and bovine liver by flame atomic absorption spectrometry [300]. The analyte was co-precipitated the complex formed was retained on the inner walls of a knitted reactor and then released by isobutyl methyl ketone and transported to the detector. Interference from iron(III) at high concentrations was circumvented, sensitivity was markedly improved and precise results were obtained. This innovation was recently exploited to remove organic selenium and determine the speciation of inorganic selenium in a flow-injection system with atomic fluorescence spectrometric detection [301]. 

AAS and AFS are used to detect metals in environmental samples in both trace and major concentrations. Analysis of metals like lead, mercury and cadmium in various samples such as tuna fish soils , mushrooms and shellfish is very common. AAS has been reported for the determination of drugs such as bromhexine, flunarizine and ranitidine hydrochlorides in pharmaceutical formulations down to concentrations of <2pg/mL . AAS has been used to analyse cadmium and lead in blood samples . The concentration ranges were 0.20-1.73 ppb and 12.0-65.7 ppb for cadmium and lead respectively. The techniques of AAS and AFS are also very popular in the analysis of herbal medicines - . ... 

Inductively coupled plasma-mass spectrometry (ICP-MS) is a modern and more sensitive variation of MS detection of bismuth. Bismuthine is generated in a hydride generator and swept by argon directly into the ICP unit. The ions are then introduced into the mass spectrometer. Optimization of the mass spectrometer, reagent, and gas flow parameters leads to a detection limit of 20ngL (IfQand 1993). Phillips etal. (2001) examined the safety aspects of colloidal bismuth subcitrate (CBS) quadruple therapy for Helicobacter pylori. These authors used ICP-MS to determine blood Bi levels in 34 patients receiving CBS quadruple therapy, with whole blood Bi levels being deter-... 

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