Monitoring Biological Samples

Another interesting application important to the pharmaceutical industry is the measurement of the absorption profile of drugs through the skin. This application is normally accomplished through the use of a Franz diffusion cell (FDC) with quantification by HPLC. IMS methods are more rapid than and compared well with HPLC results when the transdermal analyses of ibuprofen were made. Using IMS, the skin permeability coefficient was found to be 0.013 cm/h, which matched those determined using HPLC. 

More complex samples can be analyzed when IMS is coupled to MS. One example is the use of a Synapt traveling wave (TW) IMS for the metabolite profiling of leflunomide (LEF) and acetaminophen (APAP). Compared with quantitative (Q) TOF-MS and Q-TRAP-MS, the ability to provide mobility separation of the MS  

The extension of IMS to pharmaceutical applications was a natural progression from its use for illicit drug detection. Many pharmaceutical compounds are basic and thus have high proton affinities, providing both sensitivity and selectivity in a Ni ionization source or a corona discharge ionization source. In addition, the development of stand-alone ESI-IMS provides an efficient introduction and ionization method for nonvolatile pharmaceuticals such as those with high molecular weights, those that are ionic, and those that may decompose at elevated temperatures. 

The conclusion from the broad array of examples presented in this chapter is similar to that of the other chapters on IMS applications IMS, in its variety of forms, offers a viable alternate analytical method to traditional chromatographic methods, especially when cost, speed, and sensitivity are important. When samples are complex, however, as in the case of metabolomics for pharmaceutical analyses, chromatographs and MSs can be easily coupled to IMSs to achieve powerful two- and three-dimensional separations. 

Cottingham, K., Ion mobility spectrometry rediscovered. Anal. Chem. 2003, October, 435A- 39A. 

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Because of the increasing emphasis on monitoring of environmental cadmium the detemiination of extremely low concentrations of cadmium ion has been developed. Table 2 Hsts the most prevalent analytical techniques and the detection limits. In general, for soluble cadmium species, atomic absorption is the method of choice for detection of very low concentrations. Mobile prompt gamma in vivo activation analysis has been developed for the nondestmctive sampling of cadmium in biological samples (18). 

If an aromatic compound reacts with an OH radical to form a specific set of hydroxylated products that can be accurately identified and quantified in biological samples, and one or more of these products are not identical to naturally occurring hydroxylated species, i.e. not produced by normal metabolic processes, then the identification of these unnatural products can be used to monitor OH radical activity therein. This is likely to be the case if the aromatic detector molecule is present at the sites of OH radical generation at concentrations sufficient to compete with any other molecules that might scavenge OH radical. 

The duration of sampling and size of biological samples used to monitor pesticide exposure in farm workers... 

The purpose of this chapter is to describe the analytical methods that are available for detecting and/or measuring and monitoring lead in environmental media and in biological samples. The intent is not to provide an exhaustive list of analytical methods that could be used to detect and quantify lead. Rather, the intention is to identify well-established methods that are used as the standard methods of analysis. Many of the analytical methods used to detect lead in environmental samples are the methods approved by federal organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other methods presented in this chapter are those that are approved by groups such as the Association of Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). Additionally, analytical methods are included that refine previously used methods to obtain lower detection limits, and/or to improve accuracy, precision, and selectivity. 

Acrylonitrile metabolites have been measured in blood and urine, but, except for measurement of thiocyanate, these methods have not been developed for routine monitoring of exposed humans. Supercritical fluid extraction/chromatography and immunoassay analysis are two areas of intense current activity from which substantial advances in the determination of acrylonitrile and its metabolites in biological samples can be anticipated. The two techniques are complementary because supercritical fluid extraction is especially promising for the removal of analytes from sample material and immunoassay is very analyte-selective and sensitive (Vanderlaan et al. 1988). 

Singh AK, Hewetson DW, Jordon KC, et a1. 1986. Analysis of organophosphorus insecticides in biological samples by selective ion monitoring gas chromatography-mass spectrometry. J Chromatogr 369 83-96. 

Exposure. Methods for detecting chloroform in exhaled breath, blood, urine, and tissues are available. Nevertheless, it is difficult to correlate chloroform levels in biological samples with exposure, because of the volatility and short half-life of chloroform in biological tissues. Several studies monitored chloroform levels in environmentally exposed populations (Antoine et al. 1986 Hajimiragha et al. 1986 Peoples et al. 1979) however, the measured levels probably reflect both inhalation and oral exposure. Moreover, increased tissue levels of chloroform or its metabolites may reflect exposure to other chlorinated hydrocarbons. Studies to better quantitate chloroform exposure would enhance the database. 

The purpose of this chapter is to describe the analytical methods that are available for detecting and/or measuring and monitoring 1,3-DNB and 1,3,5-TNB in environmental media and in biological samples. The intent is not to provide an exhaustive list of analytical methods that could be used to detect and quantify 1,3-DNB and 1,3,5-TNB. Rather, the intention is to identify well- established... 

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