Karl H. Pearson

Semi-automated determination of chromium in whole blood and serum by Zeeman electrothermal atomic absorption spectrophotometry

Direct determination of normal and elevated levels of chromium in whole blood and serum can be achieved using Zeeman effect electrothermal atomic absorption spectrophotometry. Whole blood and serum levels of chromium were determined for an apparently healthy population and whole blood chromium levels for renal dialysis patients. Blood and serum specimens were diluted with distilled deionized water and Triton X-100. The analyses were performed utilizing air as the alternate gas to facilitate ashing in one of the char steps. Within-run precision studies for whole blood chromium determinations gave relative SD values of 4.75 and 4.65% for 0.358 and 0.172 microgram/l, respectively. Within-run precision studies for the serum chromium analysis yield relative SD values of 5.26 and 2.67% for 0.156 and 0.300 microgram/l, respectively. Detection limits were 0.025 and 0.018 microgram/l for whole blood and serum, respectively. The mean chromium level found in whole blood and serum specimens from apparently normal individuals were 0.371 microgram/l (n = 37) and 0.130 microgram/l (n = 19), with ranges of 0.120-0.673 and 0.058-0.388 microgram/l, respectively.

Separation of plasma carotenoids and quantitation of β-carotene using HPLC

Abstract A method was developed for the extraction and separation of human plasma carotenoids and quantitation of β-carotene. Carotenoids were extracted from plasma with ethanol : hexane and separated by C 18 reversed phase HPLC using spherical 3 μm packing. beta-Carotene was identified and quantitated using an external standard. The within-run precision of three different plasma pools ranged from 3.53–5.72% relative standard deviation (RSD). The between-run precision was 7.34% RSD. The method was linear to 500 μg/l with a statistical detection limit of 3.80 μg/l. Recovery of added β-carotene was from 90.41–100.37%. This method was compared to a spectrophotometric ‘total carotene’ method. The mean plasma concentrations of 25 male and 25 female human volunteers for the ‘total carotene’ were 1549 μg/l for all samples, 1487 μg/l for males and 1611 μg/l for females. The corresponding true β-carotene concentrations obtained by HPLC analysis were 134.8, 115.9 and 153.7 μg/l, respectively. The true β-carotene concentrations were on the average only 8.76% (8.07% for males and 9.46% for females) of the concentrations obtained by the spectrophotometric ‘total carotene’ method. Correlation between the methods had an r = 0.6107. The poor correlation is due to the difference in the measured components. Total carotene methods measure all solvent extractable moieties having absorbance in the 430–460 nm region, while the HPLC method quantitates true β-carotene after chromatographic separation from other carotenoids. Reference intervals were established for plasma β-carotene using REFVAL, an IFCC computer program for determining statistical reference intervals. The reference interval for all samples is 40 to 344 μg/l.

Determination of Lead in Whole Blood and Urine Using Zeeman Effect Flameless Atomic Absorption Spectroscopy

Abstract Lead is the most frequently quantitated toxic metal in biological matrices. We describe methodologies for lead determinations in whole blood and urine using Zeeman effect flameless atomic absorption spectroscopy. The whole blood determination requires a simple aqueous 1:10 dilution while the urine lead methodology utilizes a twofold dilution with 5% nitric acid. Within-run relative standard deviations (RSD) for the whole blood determination are approximately 4. 9%, while urine lead within-run PSDs are approximately 6.7%. Detection limits for both the whole blood lead determination and the urine lead determination are 3 ppb. Linearity for both assays is to 200 ppb in the diluted specimens.

Tissue Bis(2-ethylhexyl)phthalate Levels in Uremic Subjects

Abstract A method for the analysis of tissue DEHP levels was developed. Tissue homogenates were extracted with a chloroformrmethanol solution, followed by the addition of 1 g baked alumina to clean up the heavy matrices of the tissues. DEHP levels in tne tissues were determined by gas chromatography. Percent recovery of DEHP from the tissues ranged between 72.2 and 83.3%. An experimentally produced acute renal failure in dogs (performing bilateral nephrectomy) was used for comparison of DEHP distribution in tissues from Control, Sham-Operated and Nephrectomized dogs. The highest concentration of DEKP was found in lung tissues of all three groups. DEHP levels in tissues of Nephrectomized dogs were significantly higher than those of Control and Sham-Operated dogs. With the exception of brain and liver, no significant difference in tissue DEHP levels were noted for Control and Sham-Operated dogs. Liver DEHP levels were 39.4 and 65.4 μg/g tissue for the Control and Sham-Operated dogs, respectively. DEHP was f...

Separation and Quantitation of Urinary Phthalates by HPLC

Abstract A method was developed for the separation and quantitation of plasticizers and their metabolites from human urine using HPLC, Urine was diluted with an equal volume of water and extracted at pH 2.0 with diethyl ether, The extract was dried, the solvent vacuum stripped, and the residue dissolved in methanol for injection into the chromatograph. A C18 reverse phase column containing 10 μ particles was used for the analysis. Ionic suppression, 0.5% acetic acid in water, at pH 3.0 was used to resolve the acidic components. A step gradient of acetonitri1e:water (containing acetic acid) was used to elute the polar metabolites as well as the non-polar plasticizers. Mass spectrometry was used t o identify the compounds in the HPLC fractions. From the HPLC fractions of the urine extract collected, phthalic acid, MEHP, DEHP and normal urinary constituents (e.g., hippuric and benzoic acid derivatives) were identified

Human Metabolism of Bis(2-ethylhexyl)phthalate

Abstract To study the human metabolism of bis (2-ethylhexyl)-phthalate (DEHP) urine samples were analyzed from non-uremic psoriatic patients, uremic patients undergoing hemodialysis treatments and patients undergoing cardiac bypass surgery using High Performance Liquid Chromatography (HPLC). The urine of dialyzed non-uremic patients contained phthalic acid, mono (2-ethylhexyl) phthalate and bis (2-ethylhexyl) phthalate. Other compounds identified were p-hydroxy benzoic acid, m-hydroxy benzoic acid, o-hydroxy hippuric acid, o-hydroxy benzoic acid and benzoic acid, which may be either diet dependent normal urinary constituents or metabolites of bis (2-ethylhexyl) phthalate. The levels of phthalic acid and bis (2-ethylhexyl) phthalate found in the urine of patients who were on total body oxygenators containing a membrane during cardiac bypass surgery were comparable to levels obtained from non-uremic psoriatic patients. Significant levels of phthalic acid were detected in the urine of the uremic patients stu...

Quantitative Serum Amiodarone Determination by High Performance Liquid Chromatography

Abstract A HPLC method was developed for the separation and quantitation of Amiodarone from serum. Comparison of C18-reverse phase and Si-normal phase chromatography is given. The analysis requires 1 ml serum and is linear to 5000 ng Amiodarone/m1 serum. The preferred C18-reverse phase analysis is a simple, rapid and reliable method for the quantitation of Amiodarone.

Determination of zinc in whole blood, plasma and serum using Zeeman effect flame atomic absorption spectroscopy

Methods are presented for the determination of zinc in whole blood, plasma and serum using Zeeman effect flame atomic absorption spectroscopy and a flame microsampling funnel. Whole blood was diluted 1/25 with 0.10 mol/l hydrochloric acid; plasma and serum were diluted 1/5 with deionized water. Concentrations could be read directly from standards prepared in human blood pools. The within-run relative standard deviation (RSD) was 0.50%, 0.82% and 0.61% for whole blood specimens with concentrations of 4 360 micrograms/l, 5 967 micrograms/l and 8 297 micrograms/l, respectively. The within-run RSD was 2.09%, 1.16% and 0.62% for plasma specimens with zinc concentrations of 442 micrograms/l, 976 micrograms/l and 1 731 micrograms/l, respectively. The within-run RSD was 1.18%, 1.22% and 1.02% for serum specimens with zinc concentrations of 492 micrograms/l, 1 023 micrograms/l and 1 533 micrograms/l, respectively. The detection limit was 3.6 micrograms/l.

Determination of copper in whole blood, plasma and serum using Zeeman effect atomic absorption spectroscopy

Methods are presented for the determination of copper in whole blood, plasma and serum using Zeeman effect flame and furnace atomic absorption spectroscopy. Three flame measurement modes were compared: continuous aspiration, microsampling in the peak height mode and microsampling in the peak area mode. The microsampler/peak area method was the most satisfactory. The precision for the microsampler/peak area method was as follows: the within-run relative standard deviation (RSD) was 1.84% and 1.89% for whole blood specimens with copper concentrations of 983 micrograms/l and 974 micrograms/l, respectively. The within-run RSD was 2.14, 1.66 and 0.87% for plasma specimens with concentrations of 990, 1,467 and 1,963 micrograms/l, respectively. Within-run RSD was 6.64, 2.86 and 1.15% for serum specimens with concentrations of 462, 984 and 2,056 micrograms/l, respectively. The average detection limit for the microsampler/peak area method was 10.3 micrograms/l. Concentrations could be read directly from standards prepared in human whole blood, plasma or serum pools or in a commercial control.

Determination of zinc and copper in urine using Zeeman effect flame atomic absorption spectroscopy

Zinc and copper were determined in urine using polarized Zeeman effect flame atomic absorption spectrophotometry. For the zinc assay, urine was diluted 1/10 with deionized water. Concentrations could be determined by comparison to standards in a salt matrix or in a commercial urine control. The linearity of the assay was 350 micrograms/l, the detection limit was 1.2 micrograms/l and the within-run relative standard deviation (RSD) was 2.08%, 3.06%, 0.71% and 1.29% for specimens with zinc concentrations of 202 micrograms/l, 206 micrograms/l, 1 003 micrograms/l and 1 032 micrograms/l, respectively. The between-run RSD was 2.34% for a mean zinc concentration of 461 micrograms/l. For the copper assay, urine was aspirated directly and concentrations were determined by standard additions. The linearity of the assay was 5 000 micrograms/l, the detection limit was 4.6 micrograms/l and the within-run RSD was 24.49%, 16.10%, 4.00% and 3.19% for specimens with copper concentrations of 9.8 micrograms/l, 11.8 micrograms/l, 50.0 micrograms/l and 50.2 micrograms/l, respectively. The between-run RSD was 8.78% and 4.72% for specimens with copper concentrations of 21.1 micrograms/l and 40.3 micrograms/l, respectively.