Room Temperature Ionic Liquid-Based Dispersive Liquid Phase Microextraction for the Separation/Preconcentration of Trace Cd2+ as 1-(2-pyridylazo)-2-naphthol (PAN) Complex from Environmental and Biological Samples and Determined by FAAS

The current work develops a new green methodology for the separation/preconcentration of cadmium ions (Cd²⁺) using room temperature ionic liquid-dispersive liquid phase microextraction (RTIL–DLME) prior to analysis by flame atomic absorption spectrometry with microsample introduction system. Room temperature ionic liquids (RTIL) are considered “Green Solvents” for their thermally stable and non-volatile properties, here 1-butyl-3-methylimidazolium hexafluorophosphate [C₄mim][PF₆] was used as an extractant. The preconcentration of Cd²⁺ in different waters and acid digested scalp hair samples were complexed with 1-(2-pyridylazo)-2-naphthol and extracted into the fine drops of RTILs. Some significant factors influencing the extraction efficiency of Cd²⁺ and its subsequent determination, including pH, amount of ligand, volume of RTIL, dispersant solvent, sample volume, temperature, and incubation time were investigated in detail. The limit of detection and the enhancement factor under the optimal conditions were 0.05 μg/L and 50, respectively. The relative standard deviation of 100 μg/L Cd²⁺ was 4.3 %. The validity of the proposed method was checked by determining Cd²⁺ in certified reference material (TM-25.3 fortified water). The sufficient recovery (>98 %) of Cd²⁺ with the certified value. The mean concentrations of Cd in lake water 13.2, waste water 15.7 and hair sample 16.8 μg/L, respectively and the developed method was applied satisfactorily to the preconcentration and determination of Cd²⁺ in real samples.     

Correlation Between Arsenic Concentration in Fish and Human Scalp Hair of People Living in Arsenic-Contaminated and Noncontaminated Areas of Pakistan

The effects of arsenic (As) toxicity due to frequent consumption of arsenic-contaminated fish was estimated by the analysis of scalp hair of adult males, living near arsenic-contaminated area of Pakistan. For comparison purposes, scalp hair samples were also collected from the inhabitants of Hyderabad city consuming fish species with low levels of As, collected from Indus River. Concentration of As in scalp hair samples was analyzed by using hydride generation atomic absorption spectrometry (HG AAS), after microwave-assisted acid digestion. The accuracy of the As measurement was tested simultaneously analyzing certified reference material. The concentration of As in muscle tissues of fish species were found in the range of 2.11 to 14.1?μg/g and 1.92 to 12.2?μg/g, collected from arsenic-contaminated and noncontaminated areas, respectively. Exposed subjects had significantly elevated levels of As in scalp hair samples (0.72-4.94?μg/g) as compared with referent subjects (0.21-1.484?μg/g; p?相似文献   

Comparative Study of Liver Cancer Patients in Arsenic Exposed and Non-exposed Areas of Pakistan

The investigated data shows that arsenic (As) in drinking water is associated with increased mortality from different types of cancers including liver cancer. In this study, blood and scalp hair samples of male liver cancer patients and healthy referents belonging to As exposed areas of Sindh Pakistan were analyzed for As contents. The As levels in drinking water of understudy area showed that sections of this population was exposed to 3-15-folds higher concentrations of As than permissible limit. For comparative purposes, blood and scalp hair samples of matched cancerous patient as referent patients belonging to big city (Hyderabad) who have used municipal treated water with low As levels <10?μg/L were also collected. The results of this study showed that the average As concentration was higher in the blood and scalp hair of exposed and non-exposed referent cancer patients as compared to referents (p?相似文献   

Concentration of Zinc,Copper, Iron,Calcium, and Magnesium in the Serum,Tissues, and Urine of Streptozotocin-Induced Mild Diabetic Rat Model

A survey carried out in Lake Tana in 2015 found that Hg levels in some fish species exceeded internationally accepted safe levels for fish consumption. The current study assesses human exposure to Hg through fish consumption around the Lake Tana. Of particular interest was that a dietary intake of fishes is currently a health risk for Bihar Dar residents and anglers. Hair samples were collected from three different groups: anglers, college students and teachers, and daily laborers. A questionary includes gender, age, weight, activity. Frequency of fish consumption and origin of the eaten fish were completed by each participant. Mercury concentrations in hair were significantly higher (P value <0.05) for anglers (mean?±?standard deviation 0.120?±?0.199 μg/g) than college students (mean?±?standard deviation 0.018?±?0.039 μg/g) or daily workers (mean?±?standard deviation 16?±?9.5 ng/g). Anglers consumed fish more often than daily workers and college group. Moreover, there was also a strong correlation (P value <0.05) between the logarithms of total mercury and age associated with mercury concentration in scalp hair. Mercury concentrations in the hair of men were on average twice the value of the women. Also, users of skin lightening soap on a daily basis had 2.5 times greater mercury in scalp hair than non-users. Despite the different sources of mercury exposure mentioned above, the mercury concentrations of the scalp hair of participants of this study were below levels deemed to pose a threat to health.     

Determination of Arsenic in Scalp Hair of Children and its Correlation with Drinking Water in Exposed Areas of Sindh Pakistan

This study was focused on the analysis of arsenic (As) levels in scalp hair of children (age, <10 years) collected from two towns of Khairpur, Pakistan, to evaluate the effects of As-contaminated groundwater. For comparative purposes, scalp hair samples of children were also collected from that area having low levels of As (<10 μg/L) in drinking water. Groundwater and scalp hair samples of children were collected and analyzed by electrothermal atomic absorption spectrometry prior to microwave-assisted acid digestion. The average As concentrations in groundwater samples of two towns, Thari Mirwah and Gambat, were found to be 28.5 and 98.3 μg/L, respectively. The range of As concentrations in scalp hair samples of children who belong to Thari Mirwah and Gambat was 1.25-1.61 μg/g and 1.73-3.63 μg/g, respectively. Twenty percent of the total children who belong to Gambat have skin lesions on their hands and feet. A positive correlation coefficient (R = 0.91-0.99) was obtained between As contents in drinking water and scalp hairs of children of both towns.     

Modified nano-TiO2 coupled with fluorescence spectroscopy for the separation/analysis of l-tryptophan

A novel adsorbent of carboxymethyl-β-cyclodextrin modified nanometer TiO₂ (CM-β-CD/TiO₂) was prepared and used as a solid-phase extraction (SPE) material coupled to fluorescence spectroscopy determination of l-tryptophan (l-Trp) in biological samples. The experimental conditions for modified nanometer TiO₂ separation/preconcentration of l-Trp were optimized. The adsorption capacity of CM-β-CD/TiO₂ for l-Trp was 75.2 μg/g. The linear range, detection limit (DL), and the relative standard deviation (RSD) were 0.10-1.20 μg/mL, 18.8 ng/mL, and 0.67% (n = 3, 1.0 μg/mL), respectively, with a preconcentration factor of 10. The developed method was applied to determination of l-Trp in real samples and the recoveries were found to be in the range of 99.2-100.3%. For validation, a comparison material of NIC-140686 sample was analyzed and the determined value was in good agreement with the certified value.     

Evaluation of Calcium and Magnesium in Scalp Hair Samples of Population Consuming Different Drinking Water: Risk of Kidney Stone

The objective of this study was to examine the relationship between calcium (Ca) and magnesium (Mg) in underground water (UGW), bottled mineral water (BMW), and domestic treated water (DTW) with related to risk of kidney stones. The water samples were collected from different areas of Sindh, Pakistan. The scalp hair samples of both genders, age ranged 30–60 years, consuming different types of water, have or have not kidney disorders, were selected. The Ca and Mg concentrations were determined in scalp hair of study subjects and water by flame atomic absorption spectroscopy. The Ca and Mg contents in different types of drinking water, UGW, DTW, and BMW, were found in the range of 79.1–466, 23.7–140, and 45–270 mg/L and 4.43–125, 5.23–39.6, and 7.16–51.3 mg/L, respectively. It was observed that Ca concentration in the scalp hair samples of kidney stone patients consuming different types of drinking water was found to be higher (2,895–4721 μg/g) while Mg level (84.3–101 μg/g) was lower as compare to referents subjects (2,490–2,730 μg/g for Ca, 107–128 μg/g for Mg) in both genders. The positive correlation was found between Ca and Mg levels in water with related to kidney stone formations in population, especially who consumed underground water. A relative risk and odd ratio were calculated; the relative risk had a strong positive association with incidence of kidney stone which depends on types of drinking water.     

Determination of Lead in Biological Samples of Children with Different Physiological Consequences Using Cloud Point Extraction Method

In present study, lead (Pb) level in biological samples of children with physiological disorders (liver, bone, and gastrointestinal; age ranged 1–10 years) have been assessed. For comparison purpose, age-matched healthy children were also selected. Cloud point extraction (CPE) was employed for preconcentration of Pb in acid-digested biological samples prior to its determination by flame atomic absorption spectrometry (FAAS). Dithizone (diphenylthiocarbazone) and nonionic surfactant Triton X-114 (TX-114) were used as complexing reagent and extractant, respectively. The effects of several experimental variables on proposed CPE were evaluated. Under the optimum experimental conditions, the observed detection limit (LOD) and the enhancement factor (EF) were 0.08 μg L^?1 and 53, respectively. Relative standard deviation (RSD) of 10 μg L^?1 Pb was 3.4 %. It was observed that children with liver-, bone-, and gastrointestinal-related disorders had three- to fourfold higher Pb level in blood and scalp hair samples.     

Development of Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Drop for the Determination of Trace Nickel

A liquid-phase microextraction technique was developed using dispersive liquid-liquid microextraction based on solidification of floating organic drop combined with flame atomic absorption spectrometry, for the extraction and determination of trace amounts of nickel in water samples. Microextraction efficiency factors, such as the type and volume of extraction and dispersive solvents, pH, extraction time, the chelating agent amount, and ionic strength, were investigated and optimized. Under optimum conditions, the calibration graph was linear in the range of 4.23-250?μg?L(-1) with a detection limit of 1.27?μg?L(-1). The relative standard deviation for ten replicate measurements of 10 and 100?μg?L(-1) of nickel were 3.21% and 2.55%, respectively. The proposed method was assessed through the analysis of certified reference water or recovery experiments.     

Comparison of Trace Elements in the Scalp Hair of Malignant and Benign Breast Lesions Versus Healthy Women

Trace elements including Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sb, Sr, and Zn were analyzed in the scalp hair samples of women with malignant breast lesions, women with benign breast lesions, and healthy donors using atomic absorption spectrophotometric method. In the scalp hair of malignant-tumor patients, the highest average concentration was shown by Ca (1,187 μg/g), followed by Na (655 μg/g), Mg (478 μg/g), Zn (391 μg/g), Sr (152 μg/g), Fe (114 μg/g), and K (89.8), while in the case of benign-tumor patients, the average estimated element levels were 1,522, 1,093, 572, 457, 217, 80.4, and 74.7 μg/g, respectively. Most of the elements exhibited non-normal distribution evidenced by large spread, standard error, and skewness values. Mean concentrations of Ca (634 μg/g), Zn (206 μg/g), Mg (162 μg/g), Fe (129 μg/g), and Na (82.1 μg/g) were noteworthy in the scalp hair of healthy women. Average levels of Na, Sr, K, Cd, Co, Pb, Mg, Ca, Zn, Ni, Sb, and Mn were revealed to be significantly higher in the hair of malignant and benign patients compared to the healthy women; however, Fe, Cu, Al, and Cr were not significantly different in the scalp hair of the three groups. The quartile distributions of Ca, Cd, Co, Cr, K, Mg, Mn, Na, Ni, Pb, Sb, and Sr revealed maximum spread in the scalp hair of malignant and benign groups; nevertheless, Al, Cu, Fe, and Zn exhibited almost comparable quartile levels in the three groups. Strong correlation coefficients were found between Fe and Cd, Al and Na, Mn and Sr, Co and Cr, Cd and Cr, Pb and K, Pb and Mn, Cu and Na, and Al and Fe in the scalp hair of malignant-tumor patients, while Fe and K, Cd and Co, Na and Co, and Cr and Pb showed strong correlations in the scalp hair of benign-tumor patients, both of which were significantly different compared with the healthy subjects. Multivariate cluster analysis also revealed divergent clustering of the elements in the scalp hair of malignant and benign patients in comparison with the healthy women.     

Determination of trace amounts of total dissolved cationic aluminium species in environmental samples by solid phase extraction using nanometer-sized titanium dioxide and atomic spectrometry techniques

Nanometer-sized titanium dioxide was used as a solid-phase extractant for the separation and preconcentration of trace amounts of Al(III) prior to its determination by electrothermal atomic absorption spectrometry (ET AAS) and inductively coupled plasma optical emission spectrometry (ICP OES). The optimal conditions for the proposed solid phase extraction (SPE; 50 mg TiO₂, 10 min extraction time, pH 6.0, HCl and HNO₃ as eluents) and ET AAS measurement (1500 °C pyrolysis and 2600 °C atomization temperatures, Mg(NO₃)₂ as matrix modifier) were obtained. The adsorption capacity of TiO₂ was 4.1 mg Al g⁻¹ TiO₂. Two modes of the proposed procedure were compared, (I) batch and elution mode with the elution of Al from TiO₂ phase by nitric or hydrochloric acid, and (II) batch and slurry mode (without elution) with the direct TiO₂ phase-slurry sampling. Finally, the batch and slurry mode of nanometer-sized TiO₂ SPE with slurry ET AAS detection and quantification was preferred and used for the determination of trace amounts of total dissolved cationic Al species in synthetic and natural water samples. The method accuracy was checked by the analysis of lake water CRM TMDA-61 and by the technique of analyte addition (sample spiking). Under the optimal conditions, the calibration curve for batch and slurry TiO₂ SPE with a 10-fold preconcentration was linear up to 40 μg L⁻¹ Al. The limit of detection (LOD) and the limit of quantification (LOQ) was 0.11 μg L⁻¹ Al and 0.35 μg L⁻¹ Al, respectively, with a preconcentration factor of 20 and a relative standard deviation (RSD) lower than 5%.     

Determination of subnanomolar concentrations of vanadium in environmental water samples using flow injection with luminol chemiluminescence detection

A flow injection chemiluminescence method is described for the determination of subnanomolar concentrations of vanadium in environmental water samples. The procedure is based on the oxidation of luminol in the presence of dissolved oxygen catalyzed by vanadium(IV). Vanadium(V) reduction and preconcentration of vanadium(IV) was carried out using in‐line silver reductor and 8‐hydroxyquinoline chelating columns at pH 3.15, respectively. The calibration graph for vanadium(IV) was linear in the concentration range of 0.025–10 µg/L with relative standard deviation in the range of 0.4–5.58%. The detection limit (3s blank) was 3.8 × 10^?3 µg/L without preconcentration; when the vanadium(IV) was preconcentrated with an 8‐HQ column for 1 min (2.0 mL of sample loaded), the detection limit of 5.1 × 10^?4 µg/L was achieved. One analytical cycle can be completed in 2.0 min. The analysis of certified reference materials (CASS‐4, NASS‐5 and SLRS‐4) by the proposed method showed good agreement with the certified values. The method was successfully applied to the determination of total dissolved vanadium in environmental water samples. Copyright © 2010 John Wiley & Sons, Ltd.     

Determination of Arsenic Scalp Hair of Pakistani Children and Drinking Water for Environmental Risk Assessment

This cross-sectional study measured the arsenic level in scalp hair samples of children from two age groups exposed to contaminated underground water in Pakistan. The As concentrations in water and scalp hair samples were analyzed by electrothermal atomic absorption spectrometry. The studied areas were divided into three regions based on concentration of As in water and scalp hair of children who had been exposed to different levels of As through drinking water. The average As concentrations in underground water samples of sub-districts Faiz Ganj, Thari Mirwah, and Gambat were observed to be 15.2, 28.5, and 98.3 μg/L, respectively, which were marked as less, medium, and highly contaminated areas, respectively. The proportion of the children with lower body mass index significantly increased with increasing As exposure level; the dose–response relationship was consistently observed among the subgroups. The range of As concentrations in scalp hair samples of children of age 1–5 and 6–10 years was 0.21–3.88 and 0.32–3.63 μg/g, respectively. Thus, it is likely that children in our study areas are chronically exposed to As through drinking groundwater, suggesting that there is an urgent need to take immediate solution, especially in the Gambat sub-district.     

Three phases hollow fiber LPME combined with HPLC-UV for extraction, preconcentration and determination of valerenic acid in Valeriana officinalis

In the present work, the applicability of hollow fiber-based liquid phase microextraction (HF-LPME) was evaluated for the extraction and preconcentration of valerenic acid prior to its determination by reversed-phase HPLC/UV. The target drug was extracted from 5.0 mL of aqueous solution with pH 3.5 into an organic extracting solvent (dihexyl ether) impregnated in the pores of a hollow fiber and finally back extracted into 10 μ L of aqueous solution with pH 9.5 located inside the lumen of the hollow fiber. In order to obtain high extraction efficiency, the parameters affecting the HF-LPME, including pH of the donor and acceptor phases, type of organic phase, ionic strength, the volume ratio of donor to acceptor phase, stirring rate and extraction time were studied and optimized. Under the optimized conditions, enrichment factor up to 446 was achieved and the relative standard deviation (RSD) of the method was 4.36% (n = 9). The linear range was 7.5-850 μg L?1 with correlation coefficient (r2=0.999), detection limits was 2.5 μg L?1 and the LOQ was 7.5 μg L?1. The proposed method was evaluated by extraction and determination of valerenic acid in some Iranian wild species of Valerianaceae.     

Quantification of corticosteroids in bovine urine using selective solid phase extraction and reversed-phase liquid chromatography/tandem mass spectrometry

This paper presents the development of a simple liquid chromatography–tandem mass spectrometry (LC–MS/MS) method to determine corticosteroids in bovine urine sample matrices. This method uses a single phase extraction (SPE) for cleaning of the sample with an Oasis MAX cartridge at pH 9.0–9.5 and elution by a neutral organic solvent (acetonitrile/dichloromethane), followed by separation on a GEMINI C18 column in the gradient mode with acetate buffer (pH 4.1)/methanol. A triple quadrupole mass spectrometer equipped with a multimode ion source, set to negative atmospheric pressure chemical ionization (APCI) in the multiple reaction monitoring mode was used for detection. The main advantage of this method over other commonly used methods includes the use of SPE with a low volume cartridge for sample preparation and no ion suppression effects from matrix components of the urine samples in the LC–MS/MS analysis. This allowed a reduction the quantification limits (decision limits, CCα) for the first time to 0.1 μg/L (1 and 0.2 μg/L for triamcinolone and flumethasone, respectively). The developed method was validated in accordance with the European Union Commission Decision 2002/657 EC. The recoveries and within-laboratory reproducibility varied from 77% to 115% and 87% to 107.5%, respectively, at 2, 3, and 4 μg/L levels of corticosteroids. The relative standard deviation (RSD) of the measurements was lower than 30%. The decision limit was calculated by multiplying the signal-to-noise ratio by 3 and the obtained values were in the range of 0.1–1.0 μg/L, confirmed by the analysis of twenty blank samples, which were spiked at the desired concentrations. The detection capability was calculated by the addition of the decision limit and the standard deviation followed by multiplication by 1.64 of the within-laboratory reproducibility at 2 μg/L of corticosteroids. The method was applied to four urine samples, giving concentrations of prednisolone (PRED) residues in the range from 0.3 to 0.9 μg/L.     

Hair Selenium Levels in Hepatic Steatosis Patients

The purpose of this study was to assess hair selenium levels of liver patients suffering from hepatic simple steatosis and non-alcoholic steatohepatitis (NASH) in central areas of China. Selenium was measured by an atomic absorption spectrophotometer equipped with the hydride generation system. The levels of selenium in healthy individuals ranged between 0.3 and 0.9 μg/g, and mean hair selenium levels in the male population and female population were 0.59?±?0.18 and 0.57?±?0.15 μg/g, respectively. These concentrations did not vary significantly (P?>?0.05) in relation to the gender. One hundred-eighteen individuals of both sexes aged between 15 and 60 years with hepatic simple steatosis and NASH were selected for this study. The mean and standard deviation of hair selenium concentrations observed in male and female patients with hepatic simple steatosis were 0.54?±?0.16 and 0.50?±?0.15 μg/g, respectively, while the mean and standard deviation of hair selenium concentrations observed in male and female patients with NASH were 0.40?±?0.14 and 0.41?±?0.12 μg/g. Analysis of t test showed a significant difference between NASH (P?<?0.001) patients in hair selenium concentrations when compared with controls.     

Detection and Analysis of 12 Heavy Metals in Blood and Hair Sample from a General Population of Pearl River Delta Area

To detect the content of 12 heavy metals in blood and hair sample from a general population of Pearl River Delta area, and to analyze the influence of duration of residence, gender, age, smoking and drinking on the heavy metal content. Use inductively coupled plasma mass spectrometry to detect the content of 12 heavy metals lead (Pb), mercury (Hg), cadmium (Cd), aluminum (Al), arsenic (As), copper (Cu), chrome (Cr), manganese (Mn), nickel (Ni), zinc (Zn), tin (Sn) and antimony (Sb) in blood and hair samples of a total of 50 subjects from a general population, collected by multistage stratified cluster random sampling method. The geometric mean of heavy metal content in blood samples of general population (μg/L): blood aluminum 214.00; blood chrome 92.82; blood manganese 21.43; blood nickel 20.59; blood copper 0.67; blood zinc 11.50; blood arsenic 0.55; blood cadmium 2.45; blood tin 0.00; blood antimony 1.92; blood lead 158.84; and blood mercury 1.19. The geometric mean of heavy metal content in hair samples of general population (μg/g): hair aluminum is 84.65; hair chrome 0.00; hair manganese 2.44; hair nickel 0.61; hair copper 28.49; hair zinc 136.65; hair arsenic 0.75; hair cadmium 0.46; hair tin 1.04; hair antimony 0.05; hair lead 8.97; and hair mercury 0.69. Some heavy metals were correlated with duration of residence, gender, age, smoking and drinking. This was the first time that simultaneously detecting heavy metal content in blood and hair was used to analyze the internal heavy metal burden in resident population of Pearl River Delta area. These data can serve as reference for further research.     

Estimation of Toxic Metals in Scalp Hair Samples of Chronic Kidney Patients

The determination of toxic metals (TMs) in the biological samples of human beings is an important clinical screening procedure. The aim of this work is to determine total content of TMs, aluminum (Al), cadmium (Cd), nickel (Ni), and lead (Pb) in scalp hair samples of chronic kidney male patients (CKPs) on maintenance hemodialysis, during the period of 2005–2007. The study included 115 CKPs (all smokers) and 150 controls or referents [82 (nonsmokers) and 68 (smokers)]. Both controls and patients (males) were of the same age group (ranged 25–55 years), socioeconomic status, localities, and dietary habits. The scalp hair samples were analyzed by electrothermal atomic absorption spectrometer, prior to microwave-induced acid digestion. The accuracy of the total Al, Cd, Ni, and Pb measurements was tested by simultaneously analyzing certified reference material (human hair NCS ZC81002). No significant differences were observed between the analytical results and the certified values (paired t test at p > 0.05). The levels of TMs in scalp hair samples of patients were found to be higher as compared to control nonsmoker and smokers. Moreover, the study shows that levels of Al, Cd, Ni, and Pb in scalp hair samples may be useful to evaluate the impact of cigarette smoking in kidney failure patients.     

Highly Simple Deep Eutectic Solvent Extraction of Manganese in Vegetable Samples Prior to Its ICP-OES Analysis

In the present work, simple and sensitive extraction methods for selective determination of manganese have been successfully developed. The methods were based on solubilization of manganese in deep eutectic solvent medium. Three deep eutectic solvents with choline chloride (vitamin B4) and tartaric/oxalic/citric acids have been prepared. Extraction parameters were optimized with using standard reference material (1573a tomato leaves). The quantitative recovery values were obtained with 1.25 g/L sample to deep eutectic solvent (DES) volume, at 95 °C for 2 h. The limit of detection was found as 0.50, 0.34, and 1.23 μg/L for DES/tartaric, DES/oxalic, and DES/citric acid, respectively. At optimum conditions, the analytical signal was linear for the range of 10–3000 μg/L for all studied DESs with the correlation coefficient >0.99. The extraction methods were applied to different real samples such as basil herb, spinach, dill, and cucumber barks. The known amount of manganese was spiked to samples, and good recovery results were obtained.     

Hair cortisol: a parameter of chronic stress? Insights from a radiometabolism study in guinea pigs

Measurement of hair cortisol has become popular in the evaluation of chronic stress in various species. However, a sound validation is still missing. Therefore, deposition of radioactivity in hair and excretion into feces and urine after repeated injection of (3)H-cortisol was studied in guinea pigs (n?=?8). Each animal was given intraperitoneally 243.6?kBq (3)H-cortisol/day on 3 successive days. After the first injection, all voided excreta were collected for 3?days. After the second injection, hair was shaved off the animals' back and newly grown hair was obtained on day 7. Following methanol extraction, radiolabeled and unlabeled glucocorticoid metabolites (GCM) in fecal and hair samples were characterized by high-performance liquid chromatography (HPLC) and enzyme immunoassays (EIA). In feces, maximum radioactivity was reached 8?h (median) post each injection, whereas maxima in urine were detected in the first samples (median 2.5?h). Metabolites excreted into feces (13.3?%?±?3.7) or urine (86.7?%) returned nearly to background levels. HPLC of fecal extracts showed minor variation between individuals and sexes. In hair, small amounts of radioactivity were present. However, two EIAs detected large amounts of unlabeled GCM, including high levels at the position of the cortisol standard; radioactivity was absent in this fraction, demonstrating that (3)H-cortisol was metabolized. Furthermore, large amounts of immunoreactivity coinciding with a radioactive peak at the elution position of cortisone were found. These results show for the first time that only small amounts of systemically administered radioactive glucocorticoids are deposited in hair of guinea pigs, while measurement of large amounts of unlabeled GCM strongly suggests local production of glucocorticoids in hair follicles.