Simultaneous determination of tetrahydrocortisol, allotetrahydrocortisol and tetrahydrocortisone in human urine by liquid chromatography-electrospray ionization tandem mass spectrometry

Sensitive and simultaneous quantitation of 6β-hydroxycortisol and cortisol in human plasma by LC-MS/MS coupled with stable isotope dilution method

CYP3A phenotyping provides a means for personalized drug therapy. We focused our attention on the plasma 6β-hydroxycortisol (6β-OHF) to cortisol ratio as an index for CYP3A phenotyping. In the present study, we developed a sensitive and reliable method for the simultaneous determination of 6β-OHF and cortisol in human plasma using high-performance liquid chromatography/tandem mass spectrometry together with picolinylester derivatization or nonderivatization methods and 6β-[9,11,12,12-² H₄ ]hydroxycortisol and [1,2,4,19-¹³ C₄ ]cortisol as internal standards for in vivo CYP3A phenotyping in humans. The lower limits of quantification were 38.513 pg/mL for 6β-OHF and 38.100 pg/mL for cortisol. The relative error and relative standard deviation of the lower limits of quantification were <5% for both methods. The intra-day and inter-day assay reproducibilities of the determined 6β-OHF and cortisol concentrations were consistent with the actual amounts added as relative errors and relative standard deviations for both methods, which were <5.4% and <3.9%, respectively. Both methods were applied for the quantification of plasma 6β-OHF and cortisol concentrations in healthy subjects taking oral contraceptives. The absolute concentrations and time course of 6β-OHF and cortisol were found to be consistent when measured using the 2 methods. The ratio as an index for in vivo CYP3A activity decreased after 21 days of taking oral contraceptives for both methods. To the best of our knowledge, this is the first study reporting the detailed investigation of accuracy and precision in the simultaneous measurement of 6β-OHF and cortisol in human plasma using liquid chromatography/tandem mass spectrometry coupled with stable isotope dilution method, which can be applied to CYP3A phenotyping.

The evolution of methods for urinary steroid metabolomics in clinical investigations particularly in childhood

The metabolites of cortisol, and the intermediates in the pathways from cholesterol to cortisol and the adrenal sex steroids can be analysed in a single separation of steroids by gas chromatography (GC) coupled to MS to give a urinary steroid profile (USP). Steroids individually and in profile are now commonly measured in plasma by liquid chromatography (LC) coupled with MS/MS. The steroid conjugates in urine can be determined after hydrolysis and derivative formation and for the first time without hydrolysis using GC-MS, GC-MS/MS and liquid chromatography with mass spectrometry (LC-MS/MS). The evolution of the technology, practicalities and clinical applications are examined in this review. The patterns and quantities of steroids changes through childhood. Information can be obtained on production rates, from which children with steroid excess and deficiency states can be recognised when presenting with obesity, adrenarche, adrenal suppression, hypertension, adrenal tumours, intersex condition and early puberty, as examples. Genetic defects in steroid production and action can be detected by abnormalities from the GC-MS of steroids in urine. New mechanisms of steroid synthesis and metabolism have been recognised through steroid profiling. GC with tandem mass spectrometry (GC-MS/MS) has been used for the tentative identification of unknown steroids in urine from newborn infants with congenital adrenal hyperplasia. Suggestions are made as to areas for future research and for future applications of steroid profiling. As routine hospital laboratories become more familiar with the problems of chromatographic and MS analysis they can consider steroid profiling in their test repertoire although with LC-MS/MS of urinary steroids this is unlikely to become a routine test because of the availability, cost and purity of the internal standards and the complexity of data interpretation. Steroid profiling with quantitative analysis by mass spectrometry (MS) after chromatography now provides the most versatile of tests of adrenal function in childhood.

Mass spectrometric based approaches in urine metabolomics and biomarker discovery

Urine metabolomics has recently emerged as a prominent field for the discovery of non-invasive biomarkers that can detect subtle metabolic discrepancies in response to a specific disease or therapeutic intervention. Urine, compared to other biofluids, is characterized by its ease of collection, richness in metabolites and its ability to reflect imbalances of all biochemical pathways within the body. Following urine collection for metabolomic analysis, samples must be immediately frozen to quench any biogenic and/or non-biogenic chemical reactions. According to the aim of the experiment; sample preparation can vary from simple procedures such as filtration to more specific extraction protocols such as liquid-liquid extraction. Due to the lack of comprehensive studies on urine metabolome stability, higher storage temperatures (i.e. 4°C) and repetitive freeze-thaw cycles should be avoided. To date, among all analytical techniques, mass spectrometry (MS) provides the best sensitivity, selectivity and identification capabilities to analyze the majority of the metabolite composition in the urine. Combined with the qualitative and quantitative capabilities of MS, and due to the continuous improvements in its related technologies (i.e. ultra high-performance liquid chromatography [UPLC] and hydrophilic interaction liquid chromatography [HILIC]), liquid chromatography (LC)-MS is unequivocally the most utilized and the most informative analytical tool employed in urine metabolomics. Furthermore, differential isotope tagging techniques has provided a solution to ion suppression from urine matrix thus allowing for quantitative analysis. In addition to LC-MS, other MS-based technologies have been utilized in urine metabolomics. These include direct injection (infusion)-MS, capillary electrophoresis-MS and gas chromatography-MS. In this article, the current progresses of different MS-based techniques in exploring the urine metabolome as well as the recent findings in providing potentially diagnostic urinary biomarkers are discussed. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:115-134, 2017.

Endogenous glucocorticoid analysis by liquid chromatography-tandem mass spectrometry in routine clinical laboratories

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful analytical technique that offers exceptional selectivity and sensitivity. Used optimally, LC-MS/MS provides accurate and precise results for a wide range of analytes at concentrations that are difficult to quantitate with other methodologies. Its implementation into routine clinical biochemistry laboratories has revolutionised our ability to analyse small molecules such as glucocorticoids. Whereas immunoassays can suffer from matrix effects and cross-reactivity due to interactions with structural analogues, the selectivity offered by LC-MS/MS has largely overcome these limitations. As many clinical guidelines are now beginning to acknowledge the importance of the methodology used to provide results, the advantages associated with LC-MS/MS are gaining wider recognition. With their integral role in both the diagnosis and management of hypo- and hyperadrenal disorders, coupled with their widespread pharmacological use, the accurate measurement of glucocorticoids is fundamental to effective patient care. Here, we provide an up-to-date review of the LC-MS/MS techniques used to successfully measure endogenous glucocorticoids, particular reference is made to serum, urine and salivary cortisol.

Chemical derivatization for enhancing sensitivity during LC/ESI-MS/MS quantification of steroids in biological samples: a review

Sensitive and specific methods for the detection, characterization and quantification of endogenous steroids in body fluids or tissues are necessary for the diagnosis, pathological analysis and treatment of many diseases. Recently, liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) has been widely used for these purposes due to its specificity and versatility. However, the ESI efficiency and fragmentation behavior of some steroids are poor, which lead to a low sensitivity. Chemical derivatization is one of the most effective methods to improve the detection characteristics of steroids in ESI-MS/MS. Based on this background, this article reviews the recent advances in chemical derivatization for the trace quantification of steroids in biological samples by LC/ESI-MS/MS. The derivatization in ESI-MS/MS is based on tagging a proton-affinitive or permanently charged moiety on the target steroid. Introduction/formation of a fragmentable moiety suitable for the selected reaction monitoring by the derivatization also enhances the sensitivity. The stable isotope-coded derivatization procedures for the steroid analysis are also described.

Derivatization of steroids in biological samples for GC–MS and LC–MS analyses

The determination of steroids in biological samples is essential in different areas of knowledge. MS combined with either GC or LC is considered the best analytical technique for specific and sensitive determinations. However, due to the physicochemical properties of some steroids, and the low concentrations found in biological samples, the formation of a derivative prior to their analysis is required. In GC–MS determinations, derivatization is needed for generating volatile and thermally stable compounds. The improvement in terms of stability and chromatographic retention are the main reasons for selecting the derivatization agent. On the other hand, derivatization is not compulsory in LC–MS analyses and the derivatization is typically used for improving the ionization and therefore the overall sensitivity achieved.

Simultaneous determination of 18 tetrahydrocorticosteroid sulfates in human urine by liquid chromatography/electrospray ionization-tandem mass spectrometry

A liquid chromatography (LC)/electrospray ionization (ESI)-mass spectrometry (MS) method for the direct determination of eighteen tetrahydrocorticosteroid sulfates in human urine has been developed. The analytes were 3- and 21-monosulfates and 3,21-disulfates of tetrahydrocortisol (THF), tetrahydrocortisone (THE), tetrahydro-11-deoxycortisol (THS), and their corresponding 5α-H stereoisomers. The mass spectrometric behavior of these sulfates in negative-ion ESI-MS/MS revealed the production of intense structure specific product ions within the same group of sulfates and permitted distinction between regioisomeric sulfates by collision-induced fragmentation with the MS/MS technique using a linear ion-trap instrument. For the quantitative analysis, selected reaction monitoring analysis in the negative-ion detection mode using triple-stage quadrupole mass spectrometer was performed by monitoring transitions from [M-H](-) to the most abundant product ion of each tetrahydrocorticosteroid sulfate. After addition of 3- and 21-monosulfates of [2,2,3β,4,4-d5]-THF, -THE, and -THS as internal standards, urine sample was applied to a solid phase extraction using a lipophilic-weak anion exchange cartridge column, and then analyzed by LC/ESI-MS/MS. The method had satisfactory performance in terms of intra- and inter-assay precision (less than 9.7% and 9.6%, respectively), and accuracy (91.2-108.2%). The limit of quantification was lower than 2.5 ng/mL for all sulfates examined. We applied this method to determine the concentration of eighteen tetrahydrocorticosteroid sulfates in the urine of healthy subjects. Thus, we have developed a sensitive, precise and accurate assay for urinary tetrahydrocorticosteroid sulfates that should be useful for clinical and biological studies.

LC-MS/MS Method for the Simultaneous Determination of Free Urinary Steroids

Cortisol homeostasis is implicated in hypertension and metabolic syndrome. Two enzymes modulate cortisol availability; 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) preferentially converts inactive cortisone to cortisol, whereas 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) converts cortisol to cortisone. In contrast, 5α and 5β reductases inactivate cortisol by conversion to its tetrahydrometabolites: tetrahydrocortisol, allo-tetrahydrocortisol and tetrahydrocortisone. A subtle local increase in cortisol can be detected by measuring 24-h urine metabolites, LC-MS/MS being the reference method. The 11β-HSD2 activity is assessed based on the cortisol/cortisone ratio, and the 11β-HSD1 activity on the (tetrahydrocortisol + allo-tetrahydrocortisol)/tetrahydrocortisone ratio. To better understand hypertension and/or metabolic syndrome pathogenesis a method for simultaneous determination of cortisol, cortisone, tetrahydrocortisol, allo-tetrahydrocortisol and tetrahydrocortisone was developed and validated in an LC coupled with the new detector AB Sciex QTrap^® 4500 tandem mass spectrometer. The steroids were extracted from 1 mL urine, using cortisol-D4 as internal standard. The quantification range was 0.1-120 ng/mL for cortisol and cortisone, and 1-120 ng/mL for tetrahydrometabolites, with >89 % recovery for all analytes. The coefficient of variation and accuracy was <10 %, and 85-105 %, respectively. Our LC-MS/MS method is accurate and reproducible in accordance with Food and Drug Administration guidelines, showing good sensitivity and recovery. This method allows the assessment of 11β-HSD2 and 11β-HSD1 activities in a single analytical run providing an innovative tool to explain etiology of misclassified essential hypertension and/or metabolic syndrome.

Investigation of endogenous corticosteroids profiles in human urine based on liquid chromatography tandem mass spectrometry

The accurate and precise measurement of endogenous corticosteroids in urine is a powerful tool to understand the biochemical state in several diseases. In this study, a rapid, accurate, and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the quantification of 67 endogenous gluco- and mineralo-corticosteroids and progestins has been developed and validated. Sample preparation, chromatographic separation, and mass spectrometric detection were optimized. Urine samples (0.5 mL) were hydrolyzed with β-glucuronidase and the released analytes were extracted by liquid-liquid extraction. The chromatographic separation was performed in 20 min after redisolution of the extract. MS behavior of endogenous corticosteroids was evaluated in order to select the most specific precursor ion ([M+H](+), [M+NH4](+), or [M+H-nH2O](+)) for the detection. MS/MS determination was performed under selected reaction monitoring mode using electrospray ionization in positive mode. The method was shown to be linear (r>0.99) in the range of endogenous concentrations for all studied metabolites. Limits of detection (LOD) below 1 ng mL(-1) were typically obtained for analytes with a 3-oxo-4-ene structure whereas LODs below 15 ng mL(-1) were common for the rest of analytes. Recoveries were higher than 80% and intra-assay precisions below 20%, evaluated at three concentration levels, were found for most steroids. No significant or moderate matrix effect, ranging from 54 to 155%, was observed for most of the analytes. The applicability of the method was confirmed by analyzing 24h urine samples collected from twenty healthy volunteers and comparing the results with previously established normal ranges. The wide coverage of corticosteroid metabolism, together with short analysis time, low sample volume, simple sample preparation, and satisfactory quantitative results make this method useful for clinical purposes.

Tetrahydro-metabolites of cortisol and cortisone in bovine urine evaluated by HPLC-ESI-mass spectrometry

Interconversion of hormonally active cortisol (F) into the corresponding inactive 11-keto form, cortisone (E), is catalyzed by 11beta-hydroxysteroid dehydrogenases (11β-HSDs). With a view to estimating in vivo activities of some 11β-HSD isoforms, the measurement of urinary F and E and their tetrahydro metabolites (tetrahydrocortisol, THF, allotetrahydrocortisol, ATHF, tetrahydrocortisone, THE) has been suggested. The basic knowledge of THF, ATHF and THE levels in farm cattle is limited. Therefore the aim of this study was first to optimize a simple and quick method to determine F and E tetrahydro-metabolites in bovine urine by HPLC-mass spectrometry with electrospray ionization (HPLC-ESI-MS) and then to apply the method to real urine of bovines treated with prednisolone. The samples underwent filtration, deconjugation, solid-phase extraction (SPE) and the relevant analytes were measured by HPLC-ESI-MS. The method described in this paper is simple and efficient, featuring good linearity (up to 0.996) and reproducibility (6.8-12.5%, CV). Especially, good LODs were obtained, from 1.63 to 2.67 ppb, depending on the analyte. The chromatographic conditions were optimized in order to obtain a resolution which would allow to simultaneously measure two diastereoisomers, i.e. THF and ATHF. In our study, ATHF turns out to be below the detection limit, while for 18 samples tested the contents of examinated metabolites were as followed: THF (12.5±4.8 ppb), THE (10.9±5.5 ppb), F (11.6±3.3 ppb) and E (5.0±2.2 ppb). When the method was applied to the subject treated with prednisolone a major increase in the concentration of tetrahydro metabolites was observed before the slaughter, mainly due to stress conditions; prednisolone treatment, most presumably, influenced the 11β-HSD activity, as indicated by the decrease in the F/E ratio. This work may provide a useful methodological contribution to the future definition of F, E, THF, ATHF and THE urinary baseline values in order to obtain indirect evaluations of HSDs activity in farm cattle and possible applications in screenings for suspected abuse of synthetic corticosteroids in bovines.

Derivatization methods for quantitative bioanalysis by LC–MS/MS

LC with atmospheric pressure ionization MS is essential to a large number of quantitative bioanalyses for a variety of compounds, especially nonvolatile or highly polar compounds. However, in many instances, weak ionization, poor LC retention and instability of certain analytes hinder the development of the LC–MS/MS method. Chemical derivatization has been used for different classes of analytes to improve their ionization efficiency, chromatographic separation and chemical stability. This work presents an overview of chemical derivatization methods that have been applied to the quantitative LC–MS/MS analyses of nine classes of molecules, including aldehydes, amino acids, bisphosphonate drugs, carbohydrates, carboxylic acids, nucleosides and their associated analogs, steroids, thiol-containing compounds and vitamin D metabolites, in biological matrices.

Challenges and benefits of endogenous steroid analysis by LC–MS/MS

Quantification of endogenous hormonal steroids and their precursors is essential for diagnosing a wide range of endocrine disorders. Historically, these analyses have been carried out using immunoassay, but such methods are problematic, especially for low-concentration analytes, due to assay interference by other endogenous steroids. MS offers improved specificity over immunoassay and can be highly sensitive. GC–MS, with use of stable isotopically labeled internal standards, is considered the ‘gold standard’ method for serum steroid analysis. GC–MS is the method of choice for profiling steroid metabolites in urine, but these techniques are not appropriate for routine use in clinical laboratories owing to a need for extensive sample preparation, as well as analytical expertise. LC–MS/MS compares well to GC–MS in terms of accuracy, precision and sensitivity, but allows simplified sample preparation. While most publications have featured only one or a limited number of steroids, we consider that steroid paneling (which we propose as the preferred term for multitargeted steroid analysis) has great potential to enable clinicians to make a definitive diagnosis. It is adaptable for use in a number of matrices, including serum, saliva and dried blood spots. However, LC–MS/MS-based steroid analysis is not straightforward, and understanding the chemical and analytical processes involved is essential for implementation of a robust clinical service. This article discusses specific challenges in the measurement of endogenous steroids using LC–MS/MS, and provides examples of the benefits it offers.

Synthesis of 3- and 21-monosulfates of [2,2,3β,4,4-²H₅]-tetrahydrocorticosteroids in the 5β-series as internal standards for mass spectrometry

The 3- and 21-monosulfates of pentadeuterated 5β-tetrahydrocorticosteroides were synthesized, starting from cortisol and 11-deoxycotisol. The principal reactions used were (1) perdeuteration of the methylene groups adjacent to the 3-oxo group of 17,20:20,21-bismethylendioxy-5β-3-ketosteroids with NaOD in CH(3)OD followed by stereoselective reduction with NaBD(4), (2) sulfation of hydroxy groups with sulfur trioxide-trimethylamine complex, and (3) removal of the 17,20:20,21-bismethylendioxy group with hydrogen fluoride. The labeled compounds can be used as internal standards in liquid chromatography/mass spectrometry assays for clinical and biochemical studies.

Clinical steroid mass spectrometry: a 45-year history culminating in HPLC-MS/MS becoming an essential tool for patient diagnosis

Automated rapid HPLC tandem mass spectrometry has become the method of choice for clinical steroid analysis. It is replacing immunoassay techniques in most instances because it has high sensitivity, better reproducibility, greater specificity and can be used to analyze multiple steroids simultaneously. Modern multiplex instruments can analyze thousands of samples per month so even with high instrument costs the price of individual assays can be affordable. The mass spectrometry of steroids goes back decades; the first on-line chromatography/mass spectrometry methods for hormone analysis date to the 1960s. This paper reviews the evolution of mass spectrometric techniques applied to sterol and steroid measurement There have been three eras: (1) gas chromatography-mass spectrometry (GC/MS), (2) Fast Atom Bombardment (FAB) and (3) HPLC/MS. The first technique is only suitable for unconjugated steroids, the second for conjugated, and the third equally useful for free or conjugated. FAB transformed biological mass spectrometry in the 1980s but in the end was an interim technique; GC/MS retains unique qualities but is unsuited to commercial routine analysis, while LC-MS/MS is rightly stealing the show and has become the dominant method for steroid analysis in endocrinology.

Highly sensitive and specific analysis of sterol profiles in biological samples by HPLC-ESI-MS/MS

High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is a powerful method for the microanalysis of compounds in biological samples. Compared with gas chromatography-mass spectrometry (GC-MS), this method is more broadly applicable to various compounds and usually does not require a derivatization step before analysis. However, when neutral sterols are analyzed, the sensitivities of usual HPLC-MS/MS method are not superior to those of GC-MS because the sterols are relatively resistant to ionization. In this review, we introduce the recent development of HPLC-MS/MS analysis for the quantification of non-cholesterol sterols. By adding an effective derivatization step to the conventional procedure, sterol analysis by HPLC-MS/MS surpassed that obtained by GC-MS in sensitivity. In addition, sufficient specificity of this method was achieved by selected reaction monitoring (SRM) and thorough chromatographic separation of each sterol.

Steroid assays in paediatric endocrinology

Most steroid disorders of the adrenal cortex come to clinical attention in childhood and in order to investigate these problems, there are many challenges to the laboratory which need to be appreciated to a certain extent by clinicians. The analysis of sex steroids in biological fluids from neonates, over adrenarche and puberty present challenges of specificities and concentrations often in small sample sizes. Different reference ranges are also needed for interpretations. For around 40 years, quantitative assays for the steroids and their regulatory peptide hormones have been possible using immunoassay techniques. Problems are recognised and this review aims to summarise the benefits and failings of immunoassays and introduce where tandem mass spectrometry is anticipated to meet the clinical needs for steroid analysis in paediatric endocrine investigations. It is important to keep a dialogue between clinicians and the laboratory, especially when any laboratory result does not make sense in the clinical investigation.

Fusaric acid as a novel proton-affinitive derivatizing reagent for highly sensitive quantification of hydroxysteroids by LC-ESI-MS/MS

A highly sensitive derivatization method for liquid chromatography (LC)-electrospray ionization (ESI) tandem mass spectrometry of dehydroepiandrosterone (DHEA), testosterone (T), pregnenolone (P5), and 17alpha-OH-pregnenolone (17-OHP5) was developed based on the use of fusaric acid as a reagent. DHEA, P5, and 17-OHP5 were rapidly and quantitatively converted to the 3-fusarate esters by treatment with fusaric acid and 2-methyl-6-nitrobenzoic anhydride. The positive ESI-mass spectra of the fusarate esters of each steroid were dominated by the appearance of [M + H](+) as base peaks. The fusarate derivatization of these steroids showed 17.6-fold (DHEA), 11.9-fold (P5), 3.3-fold (17-OHP5), and 1.8-fold (T) higher sensitivity to those of the corresponding picolinate derivatives in LC-selected reaction monitoring.

HPLC method for determination of fluorescence derivatives of cortisol, cortisone and their tetrahydro- and allo-tetrahydro-metabolites in biological fluids

11Beta-hydroxysteroid dehydrogenase isoform 2 (11beta-HSD2) is responsible for conversion of cortisol (F) to inactive cortisone (E). Disturbance of its activity can cause hypertension. To estimate 11beta-HSD2 activity, besides F and E, their tetrahydro- (THF, THE) as well allo-tetrahydro- (allo-THF, allo-THE) metabolites should be determined. This study describes HPLC-FLD method for the quantitative determination of endogenous glucocorticoids (GCs) in plasma and urine (total and free) and their metabolites in urine. Following extraction at pH 7.4 using dichloromethane, GCs (F, E, THF, allo-THF, THE, allo-THE and internal standard--prednisolone) were derivatized with 9-anthroyl nitrile and purified by SPE using C(18) cartridges. The enzymatic hydrolysis of conjugated steroids was provided using beta-glucuronidase. The influence of organic bases on 9-AN derivatization of steroids was investigated. The best yield of the derivatization was obtained in presence of the mixture of 10.0% triethylamine (TEA) and 0.1% quinuclidine (Q). Chromatographic separation was accomplished in the Chromolith RP-18e monolithic column. The elaborated method was validated. Calibration curves were linear in the ranges: for F, E and THF 5.0-1000.0 ng mL(-1), for allo-THF and THE + allo-THE 10.0-1000.0 ng mL(-1). LOD (S/N=3:1) for all analytes amounted 3.0 ng mL(-1). Recoveries of GCs exceeded 90%. The method was precise and accurate, intra- and inter-day precision were 3.0-12.1% and 9.2-14.0%, respectively. Accuracy ranged from 0.2 to 15.1%. The method was applied for estimating endogenous GCs in plasma and urine. Plasma levels of F and E were in the ranges: 133.0-174.5 ng mL(-1) and 17.4-35.9 ng mL(-1), respectively. Free urinary steroids were in the ranges: 12.0-54.1 microg/24 h (UFF) and 37.8-76.2 microg/24 h (UFE). The ratio of (THF + allo-THF)/(THE + allo-THE) amounted from 1.01 to 1.23. The obtained results confirmed utility of the elaborated method in the assessment of 11beta-HSD2 activity in man.

Application of hyphenated mass spectrometry techniques for the analysis of urinary free glucocorticoids

Alteration of levels of glucocorticoids in plasma and urine can be related to several diseases. In particular, the determination of endogenous glucocorticoids in urine has been reported to provide information on cortisol and cortisone status, on the activities of steroid hormone enzymes and on glucocorticoid metabolism. In this study, the application of hyphenated mass spectrometry techniques (GC/MS without derivatization and LC/MS) for the simultaneous analysis of free urinary cortisol (F), cortisone (E), tetrahydrocortisol (THF), allo-tetrahydrocortisol (A-THF) and tetrahydrocortisone (THE) was evaluated. A sample preparation protocol by solid-phase extraction, mass spectrometry parameters and chromatographic conditions for both techniques were carefully optimized in terms of extracting phase and solvents, matrix effects, recovery, sensitivity and compound resolution. Baseline separation was achieved for the five underivatized analytes both in GC and LC. The LC/MS/MS technique was more suitable for the analysis of urine samples, being less influenced by matrix effects and showing excellent sensitivity and selectivity. A preliminary application of the reported method for the diagnosis of metabolic diseases was also described. The determination of each analyte in its free form, described for the first time in the paper, offers new perspectives in the application of glucocorticoid analysis for diagnostic purposes.

Quantitative metabolic profiling of 21 endogenous corticosteroids in urine by liquid chromatography-triple quadrupole-mass spectrometry

Since corticosteroid metabolism may be affected by disease states, the accurate and precise measurement of endogenous corticosteroids in urine is necessary to understand their biochemical roles. An efficient quantitative profiling of 21 endogenous corticosteroids in urine has been validated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). After enzymatic hydrolysis with beta-glucuronidase, samples were purified using a solid-phase extraction cartridge and then separated through a sub-2 microm particle C18 column (2.1 mm x 50 mm, 1.9 microm) and quantified within 12.1 min using a triple quadrupole MS with electrospray ionization in positive ion mode. All corticosteroids resulted in the base-line separation, which is even achieved for stereo-isomers, such as alpha-/beta-cortol, alpha-/beta-cortolone, and allo-tetrahydrocortisol/tetrahydrocortisol. Overall recoveries ranged from 85% to 106% with limit of quantification ranged from 0.5 to 2.0 ng mL(-1) for the corticosteroids examined. The precision (% CV) and accuracy (% bias) of the assay were 1.7-7.8% and 95.1-105.4%, respectively, in 0.5-200 ng mL(-1) calibration ranges (r(2)>0.9903), for quality-control samples containing 21 endogenous corticosteroids at three different urinary concentrations. Clinical application included quantitative analysis from patients with both prostate cancer and benign prostatic hyperplasia with altered cortisol concentrations. The described LC-MS/MS method eliminates interference from other urine components, has excellent chromatographic resolution achieved by a small particle LC column with a sufficient sensitivity to allow the profiling of both gluco- and mineralo-corticosteroids at a time.