Urine samples

Urine samples are collected in new plastic vessels (usually of polyethylene or polycarbonate). These can have a volume of 50-2000 ml, as required. If these containers are also used for transport of the sample, it is essential that they should have a screw closure with a seal. Containers with snap closures or similar are unsuitable for transportation. Even small mechanical stresses or temperature changes can affect the integrity of the seal (with possible escape of potentially infectious material or contamination of the sample). The sample should be marked with the name of the donor and the sampling time or period. 

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Description of Method. Quinine is an alkaloid used in treating malaria (it also is found in tonic water). It is a strongly fluorescent compound in dilute solutions of H2SO4 (f = 0.55). The excitation spectrum of quinine shows two absorption bands at 250 nm and 350 nm, and the emission spectrum shows a single emission band at 450 nm. Quinine is rapidly excreted from the body in urine and is easily determined by fluorescence following its extraction from the urine sample. 

Extracting the aqueous urine sample with a mixture of chloroform and isopropanol separates the quinine and chloride, with the chloride remaining in the urine sample. 

One approach is to prepare a sample blank using urine known to be free of quinine. The fluorescent signal for the sample blank is subtracted from the urine sample s measured fluorescence. 

Most potentiometric electrodes are selective for only the free, uncomplexed analyte and do not respond to complexed forms of the analyte. Solution conditions, therefore, must be carefully controlled if the purpose of the analysis is to determine the analyte s total concentration. On the other hand, this selectivity provides a significant advantage over other quantitative methods of analysis when it is necessary to determine the concentration of free ions. For example, calcium is present in urine both as free Ca + ions and as protein-bound Ca + ions. If a urine sample is analyzed by atomic absorption spectroscopy, the signal is proportional to the total concentration of Ca +, since both free and bound calcium are atomized. Analysis with a Ca + ISE, however, gives a signal that is a function of only free Ca + ions since the protein-bound ions cannot interact with the electrode s membrane. 

Blood and urine are most often analyzed for alcohol by headspace gas chromatography (qv) using an internal standard, eg, 1-propanol. Assays are straightforward and lend themselves to automation (see Automated instrumentation). Urine samples are collected as a voided specimen, ie, subjects must void their bladders, wait about 20 minutes, and then provide the urine sample. Voided urine samples provide the most accurate deterrnination of blood alcohol concentrations. Voided urine alcohol concentrations are divided by a factor of 1.3 to determine the equivalent blood alcohol concentration. The 1.3 value is used because urine has approximately one-third more water in it than blood and, at equiUbrium, there is about one-third more alcohol in the urine as in the blood. 

Several sulfate determinations in model solutions and urine samples were earried out. The results are of suffieiently good reprodueibility (within 10% rel.) and are in agreement with gravimetry and nephelometry data. This faet allows us to reeommend this method for express-determination of sulfate in urine. 

Desalting and depigmentation of urine sample was carried out by gel-filtration on Sephadex G25 with cut mass 10 kDa. 

There are numerous examples of successful application of the developed procedures using native and immobilized enzymes in analysis of environmental (waters and soils of different types, air) and biological (blood semm, urine) samples. 

A liquid chromatography-mass spectrometry (LC-MS) method that can quantitatively analyze urinar y normal and modified nucleosides in less than 30 min with a good resolution and sufficient sensitivity has been developed. Nineteen kinds of normal and modified nucleosides were determined in urine samples from 10 healthy persons and 18 breast cancer patients. Compounds were separ ated on a reverse phase Kromasil C18 column (2.1 mm I.D.) by isocratic elution mode using 20 mg/1 ammonium acetate - acetonitrile (97 3 % v/v) at 200 p.l/min. A higher sensitivity was obtained in positive atmospheric pressure chemical ionization mode APCI(-i-). 

In the future, the preventive tole of toxicology will be emphasized. It will be increasingly important to develop early indicators to monitor longterm subtle exposures that predict deleterious effects that are known to have a causal relationship with occupational exposures. In addition to collection of blood and urine samples, also collection of cells from points of... 

Fig. 1 Chromatograms of urine samples containing THC metabolites detection with fast blue salt RR (A) and fast blue salt B (B). Track Ai and B, metabolite-free urines tracks A,6 and B15 represent ca. 60 ng total cannabinoids per ml urine (determined by RIA).

The first bioanalytical application of LC-GC was presented by Grob et al. (119). These authors proposed this coupled system for the determination of diethylstilbe-strol in urine as a replacement for GC-MS. After hydrolysis, clean-up by solid-phase extraction and derivatization by pentafluorobenzyl bromide, the extract was separated with normal-phase LC by using cyclohexane/1 % tetrahydrofuran (THE) at a flow-rate of 260 p.l/min as the mobile phase. The result of LC-UV analysis of a urine sample and GC with electron-capture detection (ECD) of the LC fraction are shown in Ligures 11.8(a) and (b), respectively. The practical detection limits varied between about 0.1 and 0.3 ppb, depending on the urine being analysed. By use of... 

Figure 11.12 GC analysis of (a) urine sample spiked with opiates 3 p.g/ml) and (b) blank urine sample. Peak identification is as follows 1, dihydrocodeine 2, codeine 3, ethylmor-phine 4, moipliine 5, heroin. Reprinted from Journal of Chromatography, A 771, T. Hyotylainen et al., Determination of morphine and its analogues in urine by on-line coupled reversed-phase liquied cliromatography-gas clrromatography with on-line derivatization, pp. 360-365, copyright 1997, with permission from Elsevier Science.

Figure 11.13 (a-c) Immunoaffinity exti action-SPE-GC-FID ti aces of (a) HPLC-grade water (b) urine (c) urine spiked with /3-19-noitestosti one (0.5 p.g/1) or norethindrone and norgestrel (both 4 p.g/1) (d) SPE-GC-FID ti ace of urine. Reprinted from Analytical Chemistry, 63, A. Faijam et al., Direct inti oduction of large-volume urine samples into an on-line immunoaffinity sample pretreatment-capillary gas cliromatography system, pp. 2481-2487,1991, with permission from the American Chemical Society. 

Electropherograms of a urine sample (8 ml) spiked with non-steroidal anti-inflammatory drugs (10 p-g/ml each) after direct CE analysis (b) and at-line SPE-CE (c). Peak identification is as follows I, ibuprofen N, naproxen K, ketoprofen P, flurbiprofen. Reprinted from Journal of Chromatography, 6 719, J. R. Veraait et al., At-line solid-phase exti action for capillary electrophoresis application to negatively charged solutes, pp. 199-208, copyright 1998, with permission from Elsevier Science. 

Figure 11.19 SPME-CE analysis of urine samples (a) blank urine (a) directly injected and extracted for (b) 5 (c) 10 and (d) 30 min (b) Urine spiked with barbiturates, extracted for (e) 30 and (f, g) 5 min. Peak identification is as follows 1, pentobaitibal 2, butabarbital 3, secobarbital 4, amobarbital 5, aprobarbital 6, mephobarbital 7, butalbital 8, thiopental. Concenti ations used are 0.15-1.0 ppm (e, f) and 0.05-0.3 ppm (g). Reprinted from Analytical Chemistry, 69, S. Li and S. G. Weber, Determination of barbiturates by solid-phase microexti action and capillary electrophoresis, pp. 1217-1222, copyright 1997, with permission from the American Chemical Society.

E. Davoli, R. Fanelli and R. Bagnati, Purification and analysis of dmg residues in urine samples by on-line immunoaffinity cliromatography/bigh-performance liquid cliro-matography/continuos-flow fast atom bombardment mass spectrometry . Anal. Chem. 65 2679-2685 (1993). 

A. Earjam, J. J. Vreuls, W. J. G. M. Cuppen, U. A. Th Brinkman and G. J. de Jong, Duect introduction of large-volume urine samples into an on-line immunoaffinity sample pre-treatment-capillary gas chr omatogr aphy system . Awn/. Chem. 63 2481-2487 (1991). 

Figure 15.4 Separation of mixtures of beta-blockers by using micellar HPLC, employing the following mobile phases (a) 0.12M SDS, 5% propanol, 0.5% tiiethylamine (b) 0.06 M SDS, 15% propanol (c) 0.1 IM SDS, 8% propanol. Adapted from Journal of Chromatographic Science, 37, S. Carda-Broch et al., Analysis of urine samples containing cardiovascular drugs by micellor liquid chromatography with fluorimetric detection , pp. 93-102, 1999, with permission from Preston Publications, a division of Preston Industries, Inc.

S. Carda-Broch, I. Rapado-Maitinez, J. Esteve-Romero and M. C. Garcia-Alvarez-Coque, Analysis of urine samples containing cardiovascular drugs by micellar liquid cliromatography with fluorimetric detection , J. Chromatogr. Sci. 37 93-102 (1999). 

Polarographic methods can be used to examine food and food products biological materials herbicides, insecticides and pesticides petroleum and petroleum products pharmaceuticals. The examination of blood and urine samples is frequently carried out to establish the presence of drugs and to obtain quantitative results. 

Acids commonly found in urine Some of the acids found in urine are given in the proceeding text. We have found as many as 100 GC peaks in urine samples, which include urea and other nonacids. The following components are in order of elution. 

When a UTI has been diagnosed, sensitivity tests are performed to determine bacterial sensitivity to the drugp (antibiotics and urinary anti-infectives) that will control the infection. The nurse questions the patient regarding symptoms of the infection before instituting therapy. The nurse records the color and appearance of the urine. The nurse takes and records die vital signs. A urine sample for culture and sensitivity is obtained before the first dose of the drug is given. 

Mr. Elliott, age 42 years, had a UTI8 weeks ago. He failed to see his primary health care provider for a follow-up urine sample 2 weeks after completing his course of drug therapy. Mr. Elliot is in to see his primary health care provider because his symptoms of a UTI have recurred. The primary health care provider suspects that Mr. Elliott may not have followed instructions regarding treatment for his UTI. Analyze the situation to determine what points you would stress in a teaching plan for this patient. 

Example 3-6 Flow analysis of a urine sample at a thin-layer amperometric detector, with a flow rate of 1.25mLmin yielded a limiting current value of 1.6 pA for its unknown uric acid content. A larger current of 2.4 pA was observed for a sample containing 1 x 10 4 M uric acid and flowing at a rate of 0.9 mL min. Calculate the original concentration of uric acid in the sample. 

The pH of several solutions was measured in a hospital laboratory convert each of the following pH values into the molarity of H,CT ions (a) 5.0 (the pH of a urine sample) ... 

The tetrahydrocannabinol carboxylic acid was extracted from the urine by means of a solid state extraction cartridge packed with a Cl 8 reverse phase (octyldecyldimethyl chains). As the urine sample was used direct, and contained no added solvent, the materials of interest were irreversibly adsorbed on the reverse phase solely by dispersive interactions. 

It is appropriate at this juncture to illustrate the power of chemiluminescence in an analytical assay by comparing the limits of sensitivity of the fluorescence-based and the chemllumlnescence-based detection for analytes in a biological matrix. The quantitation of norepinephrine and dopamine in urine samples will serve as an illustrative example. Dopamine, norepinephrine, and 3,4-dihydroxybenzy-lamine (an internal standard) were derivatized with NDA/CN, and chemiluminescence was used to monitor the chromatography and determine a calibration curve (Figure 15). The limits of detection were determined to be less than 1 fmol injected. A typical chromatogram is shown in Figure 16. 

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