HPLC/tandem

For confirmatory assay, liquid chromatography-tandem mass spectrometry (LC-MS/MS) is becoming more frequently used in the analysis of OTC owing to its high sensitivity and ability. Electrospray ionization (ESI) [55-57] and atmospheric pressure chemical ionization (APCI) [41] methods combined with tandem mass spectrometry are favored because of their higher sensitivity and better reproducibility. Hamscher et al. [58] developed a method for the determination of persistent TC residues in soil fertilized with manure by HPLC tandem mass spectrometry, MS-MS, and confirmation by MS-MS-MS. Zhu et al. [59] developed an LC-tandem mass spectrometry for the analysis of common tetracyclines in water. The detection limit for oxytetracycline was 0.21 pg/L. Lykkeberg et al. [60] used LC-MS/MS for determination of oxytetracycline and its impurities EOTC, TC, ETC, ADOTC, oc-AOTC, and /i-AOTC. 

Urpi-Sarda M, Zamora-Ros R, Lamuela-Raventos R, Cherubini A, Jauregui O, de la Torre R, Covas MI, Estruch R, Jaeger W and Andres-Lacueva C. 2007. HPLC-tandem mass spectrometric method to characterize resveratrol metabolism in humans. Clin Chem 53(2) 292-299. 

The analysis of estrogens and progestogens by GC-MS has been carried out with a variety of capillary columns using helium as carrier gas [7,26,36,43, 59, 66]. LODs in the range of 0.1—1.8 ng L 1 have been achieved. In terms of sensitivity, GC- and HPLC-tandem mass spectrometry are comparable techniques. However, the derivatization carried out prior to GC separation is time consuming and can be a source of inaccuracy [7]. 

Tuomi T, Johnsson T, Reijula K. 1999. Analysis of nicotine, 3-hydroxycotinine, cotenine, and caffeine in urine of passive smokers by HPLC-tandem mass spectrometry. Clin Chem 45 2164. 

Lewis, R.J., Jones, A. and Vemoux, J.P., HPLC/tandem electrospray mass spectrometry for the determination of Sub-ppb levels of Pacific and Caribbean ciguatoxins in crude extracts of fish. Anal. Chem., 71, 1, 247, 1999. 

Phenolic and antioxidant substances have usually studied in red wines, however, recently, interest has increased in the study of bioactive phenolics in white wines Frega et al. [374] isolated and measured concentration of ethyl caffeoate in Verdicchio white wine by HPLC-tandem-mass spectrometry (HPLC-ESI-MS/MS) and they also determined its effects on hepatic stellate cells and intracellular peroxidation. The resnlts were interesting in the light of other studies demonstrating the relationship between reactive oxygen species, chronic liver injury, and hepatic fibrosis. 

Several alternative methods for the determination of sialic acid in body fluids and tissues have been described. Most of these methods make use of the classic periodate-TBA assay in combination with purification using HPLC [13]. Another method makes use of fluorometric HPLC of sialic acids after derivatization with a fluorogenic compound [9]. The most promising new method for the determination of free sialic acid in urine (and probably also other body fluids and tissues) is the HPLC-tandem mass spectrometry method [19]. This method is rapid, accurate, and sensitive, and is more robust than earlier methods. The only disadvantage is the expensive equipment that is required, which makes it only economical for specialized metabolic laboratories. Since this equipment is used for many different metabolic assays, the investment is certainly warranted, and nowadays almost essential for any metabolic laboratory. 

Table 5.4.12 The optimum HPLC-tandem mass spectrometry (MS/MSj parameters for each BA (adapted from [31]). CAD Collision-activated dissociation, MRM multiple reaction monitoring...

Kirchherr H, Kuhn-Velten WN (2006) Quantitative determination of forty-eight antidepressants and antipsychotics in human serum by HPLC tandem mass spectrometry a multi-level, single-sample approach. J Chromatogr B Anal Technol Biomed Life Sci 843 100-113... 

Storm, T., Reemtsma, T., and Jekel, M. Use of volatile amines as ionpairing agents for the HPLC-tandem mass spectrometric determination of aromatic sulphonates in industrial wastewater. J. Chromatogr. A. 1999, 854,175-195. 

D. H. Wilson, D. Sepe, and G. Barnes, Inter-laboratory differences in sirolimus results from six sirolimus testing centers using HPLC tandem mass spectrometry (LC/MS/MS), Clin. Chim. Acta 355 (2005), 211-213. 

Rindgen, D. Grotz, D. Clarke, N.J. Cox, K.A. The application of HPLC/tandem mass spectrometry for the assessment of acyl glucuronide formation in in vitro and in vivo systems in a drug discovery environment. Am. Pharm. Rev. 2001, 4, 52-58. 

The first procedure available for analysis of cyclosporine was an RIA developed by Sandoz Pharmaceuticals, the producer of cyclosporine. This immunoassay exhibits approximately 30% cross-reactivity with inactive metabolites, and the test is now considered obsolete. Nonisotopic immunoassays have been developed for whole-blood analysis. HPLC methods have been developed and are used now by many laboratories. A practical HPLC tandem mass spectrometry method is included on this book s accompanying Evolve site, found at http //evolve.elsevier.com/Tietz/ textbook/. 

Consequently, we focused our study on WSE. The taste profile of model WSE where different fi-actions of peptides (RNF, RUFl, RUFIO) were omitted, showed fiiat bitterness was mainly due to peptides, and particularly to the RUFl and the RNF fraction containing peptides widi a MW lower than 10 kDa (see 12). We paid particular attention to Aese two bitter finctions. RP-HPLC-tandem mass spectrometry led us to identify 40 peptides. Among them, 38 peptides were hydrophobic enough to be potentially bitter. Most of them were related to particular zones of casein (alpha SI and beta), with a molecular weight between 900 id 2100 (Results not shown). 

Williamson, B. L., Benson, L. M., Tomlinson, A. J., Mayeno, A. N., Gleich, G. J., and Naylor, S., On-line HPLC-tandem mass spectrometry analysis of contaminants of L-tryptophan associated with the onset of the eosinophilia-myalgia syndrome, Toxicol. Lett., 92, 139, 1997. 

A round-bottomed flask was charged with 300 mg cholesteryl linoleate (0.462 mmol) and was diluted to 0.20 M with 0.876 mL 1,4-cyclohexadiene (9.26 mmol) and 1.43 mL dry benzene. DTBN (2 mg) was added to the solution, and the sealed flask was heated to 37°C under an oxygen atmosphere. After 24 h, TLC indicated the formation of peroxidic products. Butylated hydroxytoluene (BHT, 2 mg) was added to the reaction. Analytical HPLC (tandem silicon columns, 0.5% 2-propanol in hexanes, X = 234 nm) indicated the formation of four major components in the mixture 2, /r = 15.0 min 3, Jr = 17.5 min 4, fR = 20.1 min and 5, fR = 20.5 min. Semipreparative HPLC (0.66% 2-propanol in hexane) was used to separate the components. Compounds 4 and 5 were isolated as a mixture. 

Saenger, A.K. Laha, T.J. Brerrmer, D.E. Sadrzadeh, S.M. Quantification of serum 25-hydroxyvitamin D2 and D3 using HPLC-tandem mass spectrometry and examination of reference intervals for diagnosis of vitamin D deficiency. Am. J. Clin. Pathol. 2006,125 (6), 914-920. 

Nanoscale HPLC, tandem mass spectrometer Lysis... 

Urpi-Sarda, M., Zamora-Ros, R., Lamuela-Raventos, R.M. et al. (2007). HPLC-tandem mass spec-trometric method to characterize resveratrol metabolism in humans. Clinical Chemistry, 53, 292-299. 

Speed, W. Long, J.M. Simmonds, R.J. Enos, T A. The development and vsilidation of a high performance liquid chromatography (HPLC)/tandem mass spectrometry assay for fenticonazole in human plasma and comparison with an HPLC-UV method. Rapid Commun.Mass Spectrom., 1995, 9, 1452-1456. 

Gao, S. Wilson, D.M. Edinboro, L.E. McGuire, G.M. Williams, S.G.P. Karnes, H.T. Improvement of sensitivity for the determination of propylene glycol in rat plasma and limg tissue using HPLC/tandem MS and derivatization with benzoyl chloride, J.Liq.Chromatogr.Rel.Technol., 2003,26, 3413 3431. 

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