Urine Headspace Analysis

Non-invasive PTR-MS sampling for medical applications has been used for the analysis of urine from non-smokers and habitual smokers [ 1 ]. Earlier breath analysis studies had already demonstrated that the acetonitrile level is elevated in the breath of smokers. The aim of this later study was to ascertain whether acetonitrile could also be detected in the headspace of urine and, if so, whether elevated levels are found for smokers. The study included 101 volunteers (57 men and 44 women) and the conclusion was that elevated acetonitrile levels are found in the urine of smokers. The mean (standard deviation) acetonitrile concentration in the headspace above urine of 46 non-smokers was 3.7 (1.8) ppbv, whereas for heavy smokers (defined as someone who smokes more than 30 cigarettes per day) it was found to be 28.0 (5.4) ppbv. An interesting point raised by the authors of this work was whether the increased levels of acetonitrile in the urine of smokers is a contributing factor leading to the known increase in bladder cancer for smokers compared to non-smokers. 

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Quantification. Gas Chromatography. In blood, plasma or urine headspace analysis sensitivity 2 pg/ml—R. M. Anthony et al., J. analyt. Toxicol., 1978, 2, 262-264. In blood or gastric fluid headspace analysis after conversion to acetaldehyde—J. 

Figure 8.27 A, apparatus for dynaaic headspace analysis of urine with sorbent trapping. B, gas phase stripping apparatus (purge-and-trap).

Use of SPDE/GC-MS for Analysis of African Elephant Urine Headspace... 

Urine Incubation analysis of headspace gases GC/PID 0.51 nmol/L >90 Kok and Ong 1994... 

Screening methods are available for analysis of benzene in feces and urine (Ghoos et al. 1994) and body fluids (Schuberth 1994). Both employ analysis by capillary GC with an ion trap detector (ITD). Benzene in urine has been determined by trapping benzene stripped from the urine on a Carbotrap tube, followed by thermal desorption GC/flame ionization detection (FID). The detection limit is 50 ng/L and the average recovery is approximately 82% (Ghittori et al. 1993). Benzene in urine has also been determined using headspace analysis with capillary GC/photoionization detection (PID). The detection limit is 40 ng/L (Kok and Ong 1994). 

Quantification. Gas Chromatography. In blood using head-space analysis, FID—F. N. Prior, Anaesthesia, 1972, 27, 379-389. In blo or urine trichloroethanol and trichloroacetic acid, using headspace analysis, detection limit 500 ng/ml for trichlo-... 

In direct headspace analysis, the sample e g. serum or urine, is equilibrated with the headspace in a suitable container. A protion of headspace gas is then injected for analysis. More elaborate headspace trapping devices combine separation of the volatiles from the sample matrix with subsequent enrichment of the constituents. Such a system, suitable for small volumes of body fluids, is known as the transevaporator sampling technique. It contains a microcolumn packed with Porasil E (pore silica gel), into which the sample is injected. In one mode of use, helium is passed through the column to remove the volatiles which are then collected in a trap (Tenax-GC, a porous polymer, 2,6-diphenyl-p-phenylene oxide). 

Headspace Analysis for Ethyl Alcohol in Blood, Breath, and Urine Specimens, Using a Specialized Gas Chromatograph... 

Huang J, Kumar S, Singanayagam A, et al. SIFT-MS analysis of volatile metabolites in urine headspace for the profiling of gastro-esophageal cancer. Anal Chem. 2013 85 3409-16. 

Amphetamines have also been extensively analyzed by GC-MS [2,32-36]. Recent work has focused on improvements in derivatization procedures [13], extraction techniques [1,33,35,36], and optimizing ionization parameters [14]. Solid-phase microextraction was utilized for headspace analysis of urine to determine both amphetamine and methamphetamine [32], In conjunction with the use of pentadeuterated methamphetamine as an internal standard, LODs were obtained as low as 0.1 llg/ml for both compounds monitored in the SIM mode and using isobutane CL This method was found to be 20 times more sensitive than traditional headspace analysis of urine without SPME extraction [32]. Even lower limits of detection were obtained utilizing derivatization of amphetamine and methamphetamine with propylchloroformate and LLE of the propylcarbamate derivatives from urine [13]. When deuterated amphetamine and methamphetamine were used as internal standards, the LODs were 25 ng/ml for both drugs the LOD improved to 5 ng/ml when Wpropylamphetamine was used as the internal standard. In this case, ions were formed via El and SIM was used (Fig. 4) [13]. This method was shown to be rugged and relatively free from potential interferences from other related drugs. 

Non-invasive PTR-MS sampling for medical applications has been used for headspace analysis above urine [1] and fluids obtained from the gut during colonoscopy [2], the in vitro discrimination of cancerous and non-cancerous cell lines [3] and for studies of emissions from the skin [4-6]. PTR-MS has also been used for investigations involving occupational health exposure in various medical environments [7-10]. Other medical-related work has... 

The use of PTR-MS in medical science is not just restricted to breath analysis and online in vitro measurements of microbial cultures. PTR-MS has considerable potential for application in other medical areas, such as the analysis of the headspace above liquid and solid biological samples (e.g. urine, faeces or sputum samples) or detecting emissions from skin (a potential application being the early detection of skin cancers), but surprisingly there have been only a limited number of such studies at the time of writing. Furthermore, with the development of direct aqueous injection inlet systems (see Section 9.2), PTR-MS is not just limited to headspace analysis but now also has the potential to analyse liquid samples directly. 

Fig. 4.3 Behavioral bioassay by using a felinine derivative. Felinine purified from cat urine by HPLC was dissolved in water at a concentration of lOmg/ml, and 200 pi of the solution was stored in a 1.5-ml eppendorf tube at room temperature for 5 days. GC-MS analysis detected 3-mercapto-3-methyl-l-butanol in the headspace gas of the tube. The cat (6-year-old castrated male) was able to sniff the opening of the tube, but not contact the felinine solution. The cat sniffed 3-mercapto-3-methyl-l-butanol with considerable interest (18s and 25s) and then licked his lips five times (37 s)...

Some methods are available for determining -hexane in urine and tissues. A modified dynamic headspace extraction method for urine, mother s milk, and adipose tissue has been reported (Michael et al. 1980). Volatiles swept from the sample are analyzed by capillary GC/FID. Acceptable recovery was reported for model compounds detection limits were not reported (Michael et al. 1980). A solvent extraction procedure utilizing isotope dilution followed by GC/MS analysis has been reported for tissues (White et al. 1979). Recovery was good (104%) and detection limits are approximately 100 ng/mL (White etal. 1979). 

Blood, urine Blood collected into vacutainers containing EDTA. Two-mL aliquots of blood or urine dispensed into headspace vials for analysis Headspace GC/ECD No data No data Cammann and Hubner 1995... 

Blood, urine, and tissues Addition of sample to internal standard addition of proteolytic enzyme equilibration at elevated temperature analysis of headspace gas GC/ECD At least 1 ppm No data Streete et al. 1992... 

Methods are available for monitoring 1,4-dichlorobenzene in urine and tissues, particularly adipose tissue and mother s milk. Solvent extraction, silica gel column clean-up, and GC/ECD or GC/PID analysis has been used for urine (Langhorst and Nestrick 1979), mother s milk (Jan 1983), and adipose tissue (Jan 1983). Recovery is good (>80% recovery) and detection limits are in the low-ppb range (Jan 1983 Langhorst and Nestrick 1979). Headspace purge, followed by capillarity GC/MS analysis has been utilized for urine (Michael et al. 1980), mother s milk (Erickson et al. 1980), and tissue (Pellizzari et al. 1985). Recovery, where reported, is adequate (>60%) (Erickson et al. 1980), and detection limits are in the low-ppb range (Erickson et al. 1980). 

Determination of the intact CW agents in urine or blood may proceed by the methods commonly applied to water samples. Extraction with an organic solvent and subsequent cleanup with a Florisil column is a well-established procedure. Rather volatile, scheduled compounds can often be successfully recovered and purified from biological materials by means of dynamic headspace stripping and subsequent adsorption on Tenax tubes these tubes are then subjected to GC/MS analysis. 

Wils et al. (25,26) previously reported an entirely different approach to TDG analysis. TDG in urine was converted back to sulfur mustard by treatment with concentrated HC1. The sample treatment is less straightforward than the methods described above, but analysis as sulfur mustard is facile. Urine, plus 2H8-TDG as internal standard, was cleaned up by elution through two C18 cartridges. Concentrated HC1 was added and the sample stirred and heated at 120 °C. Nitrogen was blown over the solution and sulfur mustard isolated from the headspace by adsorption onto Tenax-TA. The method was used to detect TDG in urine from casualties of CW attacks (see below). A disadvantage of this method is that it may convert metabolites other than TDG to sulfur mustard. This is supported by the detection of relatively high levels of analytes in urine from control subjects. Vycudilik (27) used a similar procedure, but recovered the mustard by steam distillation and extraction. 

A static headspace is frequently used for the determination of VOCs in complex matrices such as food [32, 33], urine [34], blood [35], and swimming pool water [36]. This method is also routinely used in the analysis of residual solvents in the pharmaceutical industry [37]. Currently, there are various types of automatic HS systems (Fig. 14.5) [38]. 

SIFT-MS was used for the analysis of VOCs present in air samples [127]. Substances such as ammonia, isoprene, acetone, ethanol, and acetonitrile were detected at ppb levels. SIFT-MS was also applied to analysis of blood [126], urine [128], food [129], and headspace from lung cancer cells [130]. The spectrum of exhaled air is presented in Fig. 14.10. 

Prison et al. (1998) describes a method using sohd-phase microextraction of GHB in plasma and urine. This is a new approach for GHB analysis that shows promise in that it is simple, sensitive and requires only 0.5 mL of specimen. The linearity range was from 1 to 100 pg mL in plasma and from 5 to 150 pg mL in urine with a Emit of detection of 0.05 and 0.1 pg mL for plasma and urine, respectively. The limit of detection was calculated based on aqueous solutions because the blank plasma and urine specimens had endogenous GHB concentrations of 0.1-0.2 and 0.5-L5pgmL, respectively. The method required conversion of GHB to GBL with GBL-de as the internal standard and detection by headspace GC-MS with spectra from both CI and El ionization modes. Many methods are available for GHB and GBL analyses depending on the equipment and resources available to the laboratory. 

Analytical Methods for Urine and Blood. Specific biomarkers of lewisite exposure are currently based on a very limited number of in vitro experiments (Jakubowski et al., 1993 Wooten et al., 2002) and animal studies (Logan et al., 1999 Fidder et al., 2000). Wooten et al. (2002) developed a solid-phase microextraction (SPME) headspace sampling method for urine samples followed by GC-MS analysis. It is the most sensitive method reported to date with a lower limit of detection of 7.4 pg/mL. Animal experiments have been limited in number and in their scope. In one study of four animals, guinea pigs were given a subcutaneous dose of lewisite (0.5 mg/kg). Urine samples were analyzed for CVAA using both GC-MS and GC coupled with an atomic emission spectrometer set for elemental arsenic (Logan et al., 1999). The excretion profile indicated a very rapid elimination of CVAA in the urine. The mean concentrations detected were 3.5 pg/mL, 250 ng/mL, and 50 ng/mL for the 0-8, 8-16, and 16-24 h samples, respectively. Trace level concentrations... 

Several SP materials have been used for the extraction of FRs from aqueous samples, plasma and milk (Table 31.7). Similar materials have been used for all FRs. Typical SP materials include Ci8 and Cg bonded to porous silica, highly cross-linked poly(styrene divinylbenzene) (PS-DVB), and graphitized carbon black (GCB). It is also possible to use XAD-2 resin for extraction of various FRs, pesticides, and plastic additives from large volumes of water (100 1). The analytes can then be either eluted from the resin by acetone hexane mixture, or Soxhlet extracted with acetone and hexane. For a specific determination of diphenyl phosphate in water and urine, molecularly imprinted polymers have been used in the solid phase extraction. The imprinted polymer was prepared using 2-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross linker, and a structural analog of the analyte as the template molecule. Elution was done with methanol triethylamine as solvent. Also solid phase microextraction (SPME) has been applied in the analysis of PBDEs in water samples. The extraction has been done from a headspace of a heated water sample (100°C) using polydimethylsiloxane (PDMS) or polyacryl (PA) as the fiber material. ... 

The main congeners of forensic interest are methanol, n-propanol, isobutanol, 2- butanol, and its metabolite methyl ethyl ketone and n- butanol, while isopropanol and acetone are endogenous substances always detected in blood and urine during a congener analysis by headspace gas chromatography. However, these substances are not ingredients of alcoholic beverages (Iffland Jones, 2003). 

Use of the SPB-1 column system A qualitative standard mixture is first analyzed (see Figure 1). A reagent blank analysis is then performed to monitor interference from the laboratory atmosphere. A sealed headspace vial containing internal standard solution (1,1,2-trichloroethane - - ethylbenzene in analyte-free diluted whole blood) is incubated (65°C, 15 min) and a portion (100-300 pi) of the headspace is taken for analysis using a warmed (40°C) gas-tight glass syringe. Subsequently, the sample (whole blood, plasma, serum, or urine) (200 pi) is added to the same vial and, after reincubation (65°C, 15 min), a further portion of headspace is taken for analysis. 

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