Determination of vanadium in urine by electrothermal atomic absorption spectrometry

After wet ashing of the urine sample with nitric acid, vanadium is chelated with cupferron, extracted into 4-methylpentan-2-one and determined by atomic absorption spectrometry with a pyrolytically-coated graphite furnace atomizer. The sensitivity allows the precise determination of 1–500 μg V l^-1 in urine. The coefficient of variation for triplicate urine measurements is <8% for 10 μg V l^-1.     

Headspace single-drop microextraction coupled with gas chromatography electron capture detection of butanone derivative for determination of iodine in milk powder and urine

A new detection method using headspace single-drop microextraction (HS-SDME) coupled to gas chromatography (GC) was established to determine the iodine in milk powder and urine. The derivative from the reaction between iodine and butanone in the acidic media was extracted into a micro-drop then determined by GC-ECD. With the optimisation of HS-SDME and derivatisation, the calibration curve showed good linearity within the range of 0.004–0.1 μg mL^?1 (0.004–0.1 μg g^?1) (R ² = 0.9991), and the limits of detection for milk powder and urine were 0.0018 μg g^?1 and 0.36 μg L^?1, respectively. The mean recoveries of milk powder and urine were 90.0–107 % and 89.4–101 % with mean RSD of 1.7–3.4 % and 2.7–3.3 %, respectively. This detection method affords a number of advantages, such as being simple, rapid, and inexpensive, with low organic solvent consumption, and is remarkably free from interference effects, rendering it an efficient method for the determination of iodine in milk powder and urine samples.     

C and N stable isotope variation in urine and milk of cattle depending on the diet

The stable carbon and nitrogen isotopic composition of urine and milk samples from cattle under different feeding regimes were analysed over a period of six months. The isotope ratios were measured with isotope ratio mass spectrometry (IRMS). The δ ¹³C values of milk and urine were dependent on different feeding regimes based on C₃ or C₄ plants. The δ ¹³C values are more negative under grass feeding than under maize feeding. The δ ¹³C values of milk are more negative compared to urine and independent of the feeding regime. Under grass feeding the analysed milk and urine samples are enriched in ¹³C relative to the feed, whereas under maize feeding the ¹³C/¹²C ratio of urine is in the same range and milk is depleted in ¹³C relative to the diet. The difference between the ¹⁵N/¹⁴N ratios for the two feeding regimes is less pronounced than the ¹³C/¹²C ratios. The δ ¹⁵N values in urine require more time to reach the new equilibrium, whereas the milk samples show no significant differences between the two feeding regimes.     

Square-wave voltammetric determination of cefoperazone in a bacterial culture,pharmaceutical drug,milk, and urine

Use of square-wave voltammetry (SWV) for determination of cefoperazone (CFPZ) in some buffers, bacterial culture, urine, and milk is described. CFPZ provides a specific voltammetric signal which is affected by pH and solution components. Determination of CFPZ in Britton–Robinson buffer, pH 4.4, is sensitive with a low detection limit (about 0.5 nmol L^–1). In a more complex medium (bacterial 2YT medium, pH 7.2) the detection limit was approximately 1.5 mol L^–1. We provide evidence that SWV is a suitable and quick method for CFPZ determination in a culture of living bacteria without separation of biomass. We have found big differences between methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) in cultivation in the presence of CFPZ, depending on time. When CFPZ is cleaved by penicillinase, a new SWV peak b appears at more positive potentials. This peak rises both with increasing concentration of enzyme and with cleavage time while the original CFPZ peak is simultaneously decreasing. We determined the concentration of CFPZ in the drug Pathozone by the standard addition method and achieved good agreement with the declared value of CFPZ in the drug. With a simple pretreatment procedure it is possible to determine CFPZ in milk; for urine no pretreatment was required. Using SWV we could detect CFPZ concentrations as low as 500 nmol L^–1 in bovine milk and human urine.     

Nickel determination in biological materials at ultratrace level by fast neutron radiochemical activation analysis

Using radiochemical separation of cobalt following the fast neutron reaction⁵⁸Ni(n, p.)⁵⁸Co and long high fluence irradiation, we attempted to improve the determination limit for Ni to the nanogram and sub-nanogram level. A Compton suppression spectrometer was shown to be the best choice compared to co-axial or well-type HPGe detectors. Results for low level biological reference materials such as serum and milk powder are discussed. Use of both dried and pre-ashed samples showed that losses of Ni and Co on ashing are non-significant. The influence of the silica ampoule blank was also investigated.     

Rapid determination of 239Pu in urine samples using molecular recognition technology product AnaLig®Pu-02 gel

This paper describes the use of IBC′s AnaLig^®Pu-02 molecular recognition technology product to effectively and selectively pre-concentrate, separate and recover plutonium from urine samples. This method uses two-stage column separations consisting of two different commercial products, Eichrom’s Pre-filter Material and AnaLig^®Pu-02 resin from IBC Advanced Technologies. By eliminating the co-precipitation techniques and the ashing steps to remove residual organics, the analysis time was reduced significantly. The method was successfully tested by adding known activities of reference solutions of ²⁴²Pu and ²³⁹Pu to urine samples.     

Trace iodine quantitation in biological samples by mass spectrometric methods: The optimum internal standard

Accurate quantitation of iodine in biological samples is essential for studies of nutrition and medicine, as well as for epidemiological studies for monitoring intake of this essential nutrient. Despite the importance of accurate measurement, a standardized method for iodine analysis of biological samples is yet to be established. We have evaluated the effectiveness of ⁷²Ge, ¹¹⁵In, and ¹²⁹I as internal standards for measurement of iodine in milk and urine samples by induction coupled plasma mass spectrometry (ICP-MS) and of ³⁵Cl¹⁸O₄⁻, ¹²⁹I⁻, and 2-chlorobenzenesulfonate (2-CBS) as internal standards for ion chromatography-tandem mass spectrometry (IC-MS/MS). We found recovery of iodine to be markedly low when IC-MS/MS was used without an internal standard. Percent recovery was similarly low using ³⁵Cl¹⁸O₄ as an internal standard for milk and unpredictable when used for urine. 2-Chlorobenzebenzenesulfonate provided accurate recovery of iodine from milk, but overestimated iodine in urine samples by as much as a factor of 2. Percent recovery of iodine from milk and urine using ICP-MS without an internal standard was ∼120%. Use of ¹¹⁵In predicted approximately 60% of known values for both milk and urine samples. ⁷²Ge provided reasonable and consistent percent recovery for iodine in milk samples (∼108%) but resulted in ∼80% recovery of iodine from urine. Use of ¹²⁹I as an internal standard resulted in excellent recovery of iodine from both milk and urine samples using either IC-MS/MS and ICP-MS.     

Determination of copper in milk powder by electrothermal atomic absorption and atomic emission spectrometry

Summary Electrothermal atomic absorption spectrometry (ETA-AAS) and atomic emission spectrometry (ETA-AES) have been applied to the determination of copper in powdered milk. A homogeneous dispersion procedure for the preparation of the milk powder is described which was found to be simple, rapid and less susceptible to contamination than dry ashing or wet digestion methods. Both ETA-AAS and ETA-AES techniques were found to provide satisfactory results using conventional tube wall atomisation only when the method of standard additions was employed. The application of graphite probe atomisation in ETA-AES and ETA-AAS allowed the development of direct methods for the determination of copper in milk powder using aqueous standard calibration curves. The accuracy of the probe ETA-AAS method was confirmed using new reference materials prepared by the EEC Community Bureau of Reference. Acceptable agreement was obtained for the other procedures using a commercial milk powder sample with a copper content of 6.0g g^–1.     

Sensitive determination of tilmicosin,erythromycin ethylsuccinate and clindamycin by CE with electrochemiluminescence detection using azithromycin as internal standard and its applications

A sensitive approach for the simultaneous determination of tilmicosin, erythromycin ethylsuccinate and clindamycin was developed by CE coupled with electrochemiluminescence detection with ionic liquid. The parameters for CE, electrochemiluminescence detection and the effect of ionic liquid were investigated systematically. The three analytes were well separated and detected within 8 min. The limits of detection (S/N=3) of tilmicosin, erythromycin ethylsuccinate and clindamycin are 3.4×10^?9, 2.3×10^?8 and 1.3×10^?8 mol/L, respectively. The precisions (RSD%) of the peak area and the migration time are from 0.8 to 1.5% and from 0.2 to 0.5% within a day and from 1.8 to 2.7% and from 0.6 to 0.8% in 3 days, respectively. The limits of quantitation (S/N=10) of tilmicosin, erythromycin ethylsuccinate and clindamycin are 3.2×10^?8, 2.9×10^?7 and 9.1×10^?8 mol/L in human urines and 5.5×10^?8, 3.2×10^?7 and 2.1×10^?7 mol/L in milk samples, respectively. The recoveries of three analytes at different concentration levels in urine, milk and drugs are between 90.0 and 104.7%. The proposed method was successfully applied to the determination of three analytes in human urine, milk and drugs.     

Hot-injection procedures for the rapid analysis of biological samples by electrothermal atomic-absorption spectrometry

The combination of palladium/hydrogen matrix-modification and injection of samples into a graphite tube at 120 degrees has allowed the accurate determination of copper, iron, lead and nickel in biological reference materials (urine, milk powder and bovine liver). Palladium modification allowed the use of a standard ashing temperature of 1000 degrees for all four elements. Direct aqueous calibration was applied without the need for standard additions. The total heating cycle, from the start of sample injection, took 45 sec.     

A routine method for the determination of plutonium in urine with a low detection limit

A radiochemical method for the determination of plutonium in urine is described. The steps involved are a) co-precipitation of plutonium, b) wet ashing, c) hydrolysis, d) extraction from 2M HNO₃ into capillary polypropylene columns coated with tri-n-octyl phosphineoxide 0.5M in toluene, and e) back-extraction of plutonium from the organic phase, f) electroplating onto stainless steel disks and spectrometry, since plutonium is extracted together with small amounts of uranium naturally occurring in urine. High quality deposits for spectrometry are obtained because iron interference is eliminated before back-extraction. The radiochemical recovery of²³⁹Pu is 55.6±7.5% and the detection limit is 1.0 mBq per liter of urine.     

Dimethyldioctadecylanimonium bentonite immobilized magnetic chitosan nanoparticles as an efficient adsorbent for vortex-assisted magnetic dispersive micro-solid-phase extraction of celecoxib from human breast milk,plasma and urine samples

A polymer/layered silicate composite based on dimethyldioctadecylanimonium bentonite/chitosan magnetic nanoparticles was synthesized and characterized by field emission transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectrometry. The prepared nanocomposite was used to isolate and preconcentrate celecoxib from human breast milk, urine and plasma samples. In this method, dimethyldioctadecylanimonium bentonite increases the accessibility of binding sites and adsorption capacity by high microporosity and large surface area, that has been realized for the first time in a magnetic chitosan nanoparticle support. A fractional factorial design was utilized for screening the experimental parameters. The effective parameters were then optimized by Box–Behnken design. Under the optimized conditions, the developed method exhibited wide linear ranges of 5–500 μg L⁻¹ for plasma and urine and 10–500 μg L⁻¹ for breast milk samples with satisfactory recoveries in the range of 96.7–99.0%. Limit of detection and quantification of celecoxib were in the ranges 0.3–3.2 and 0.99–10.56, respectively. The enrichment factors were obtained in the ranges 64.5–66.0, while precisions were <3.7%.     

Carrier-free estimation of106Ru in urine

A simple carrier-free method has been developed for estimating 0.1 to 1.1 Bq of¹⁰⁶Ru in urine. The organic matter present in urine samples was completely destroyed by wet ashing using nitric acid-peroxide mixture in presence of sulfuric acid. Ruthenium was oxidized to tetroxide using potassium periodate and allowed to react in-situ with polyethylene powder. The powder was separated, washed, pelletized and its -activity was counted. Recovery of¹⁰⁶Ru is found to be better than 80% with a minimum detection limit of 0.2 Bq/dm³ which is less than the DRL value specified by International Commission on Radiological Protection (ICRP).     

Aufschluß und Veraschung organischer Substanzen durch Radikale in wäßriger Lösung

The method described utilizes the OH radicals formed from the reagent H₂O₂/Fe²⁺ in aqueous solution. It is especially suitable for foodstuffs (as meat, fish, flour), biological material (as animal carcases, faeces, urine) and various chemicals. The parameters of the method have been investigated with the wet-ashing of meat as example. Mild experimental conditions, large amounts of substances which can be ashed and simple manipulation in an open system are the essential advantages in comparison with methods hitherto used. The procedure is useful for analytical decomposition and ashing, for serial operation, as a rapid method, and for destruction of waste. In the present communication it is applied to the control of environmental radioactivity in the determination of very low activities of ¹³⁷Cs in meat and to the rapid and reliable measurement of accidental contaminations.     

Simultaneous enrichment of aluminium and lead with cupferron on activated carbon for determination in milk and fruit juices by atomic absorption spectrometry

An enrichment method has been modified for the determination of Al in animal milk and fruit juices by flame atomic absorption spectrometry (FAAS). The samples were digested by wet ashing. 8-Hydroxyquinoline and cupferron were used as complexing reagents for adsorption of the Al complexes on activated carbon. The pH values for maximum recovery of Al were in the ranges 4.4–6.0 for cupferron and 8.0–9.0 for oxine. The relative standard deviation was 4% for an aluminium concentration of 120 gL^–1 using cupferron. Optimum conditions for lead enrichment were taken from previous work on the cupferronactivated carbon enrichment method. The optimized procedure was applied to the determination of Al and Pb in animal milk and fruit juices by FAAS. Simultaneous enrichment of these two elements was achieved at the same pH.     

Cadmium losses on wet and dry ashing of plant materials

Cadmium losses on wet and dry ashing were studied using tomato leaves with metabolized¹⁰⁹Cd radiotracer. The most appreciable Cd losses (up to 35%) occured when sulphuric acid was used on wet ashing due to Cd retention in the CaSO₄ precipitate formed. Only trace amounts of Cd were retained in a silicaceous precipitate resulting from wet ashing in the absence of sulphuric and hydrofluoric acids in the decomposition mixtures employed. Small Cd losses (up to 7%) were observed on dry ashing in the air in open systems at temperatures not exceeding 500°C. Cd losses increased, however, to 30% when the final ashing temperature was raised to 900°C. Incorporation of the¹⁰⁹Cd radiotracer into various parts of tomato plants and its distribution between soil and the plants are also briefly reported.     

The daily radon dose in body organs caused by drinking milk and water

Milk is considered as the richest nutrition, being used by people. When drinking milk or water the radon gas will transfer from air to them rapidly. Since milk is majorly composed of water, probably radon existence in livestock consumable water could be the main cause of its presence in milk. Different portion of milk changed by radon gamma ray and consumption of radon included water or milk has its effects on the human body. For investigation the effect of radon in water or milk on human organs, this study has been done in two phases with MCNPX software. In the first phase, the dose rate of absorbed gamma ray by different portion of milk which is indoctrinated by 1 Bq/m³ of radon during a day is calculated. Moreover, the effects shown by milk and its components in radon gamma spectrum, which is demonstrator of milk absorption spectrum, are also surveyed. In the second phase as well, according to the human body phantom, the absorbed gamma dose caused by daily consumption of indoctrinated water or milk with 1 Bq/m³ radon is calculated. The production rate of free radicals in milk and its different components are derived according to escape data of MCNPX code.     

The determination of platinum in biological materials by electrothermal atomic absorption spectroscopy

Methods for determination of platinum in body tissues and fluids by electrothermal atomic absorption spectroscopy are described. Serum and urine could be analyzed without pretreatment or dilution. Wet and dry ashing techniques for tissue digestion were compared. Dry ashing tissues in a furnace resulted in significant and unexplained losses of analyte, whereas there was complete recovery of platinum added to the tissues when the tissues were wet ashed. The wet ashing technique is fast and convenient and requires minimal sample treatment.     

Microwave digestion and matrix separation for the determination of cadmium in urine samples by electrothermal atomization atomic absorption spectrometry using a fast temperature program

 A method is proposed which involves sample pretreatment followed by electrothermal atomic absorption spectrometry (ETAAS) for determination of cadmium in human urine. A microwave digestion system was devised to accommodate double-closed vessels for simultaneous digestion of batches of up to 24 urine samples in about 20 min. After digestion, matrix substances which might interfere were removed using silica-immobilized 8-hydroxyquinoline (I-8HOQ) columns. The analyte adsorbed on the column was then eluted with dilute nitric acid solution and determined by ETAAS using a fast temperature program. Neither ashing steps in the furnace heating program nor use of matrix modifiers was necessary. The accuracy, precision, limit of detection, and sample throughput of the method were evaluated. With meticulous control of systematic errors which may be introduced in the pretreatment procedures, the present method can serve as a reference technique for the analysis of Cd in urine samples. Received: 29 July 1996/Revised: 30 September 1996/Accepted: 13 October 1996     

Microwave digestion and matrix separation for the determination of cadmium in urine samples by electrothermal atomization atomic absorption spectrometry using a fast temperature program

 A method is proposed which involves sample pretreatment followed by electrothermal atomic absorption spectrometry (ETAAS) for determination of cadmium in human urine. A microwave digestion system was devised to accommodate double-closed vessels for simultaneous digestion of batches of up to 24 urine samples in about 20 min. After digestion, matrix substances which might interfere were removed using silica-immobilized 8-hydroxyquinoline (I-8HOQ) columns. The analyte adsorbed on the column was then eluted with dilute nitric acid solution and determined by ETAAS using a fast temperature program. Neither ashing steps in the furnace heating program nor use of matrix modifiers was necessary. The accuracy, precision, limit of detection, and sample throughput of the method were evaluated. With meticulous control of systematic errors which may be introduced in the pretreatment procedures, the present method can serve as a reference technique for the analysis of Cd in urine samples. Received: 29 July 1996/Revised: 30 September 1996/Accepted: 13 October 1996