Development of a fast and reliable methodology for the determination of polyamines in urine by using a guard column as a low-resolution fractioning step prior to mass spectrometry. Comparison with flow injection-mass spectrometry analysis

Use of a guard column coupled to mass spectrometry as a fast semi-quantitative methodology for the determination of plasticizer metabolites in urine

For the first time, a very simple and fast method combining the use of a guard column coupled to tandem mass spectrometry (guard column-MS/MS) has been proposed for the determination of plasticizer metabolites in urine. Briefly, samples (1.0 mL) were submitted to enzymatic hydrolysis for 10 min, filtered, diluted 1/10 v/v with ultrapure water and directly injected into the system. A fast run of only 2 min (3 min including the injection cycle) allowed the determination of 19 analytes. Enzymatic hydrolysis, filtering material, and guard column-MS/MS conditions were optimized. Intra-day precision at the low-level concentration (expressed as relative standard deviation, %RSD) obtained from the analysis of synthetic urine samples varied between 11 and 20%. Limits of quantification ranged from 2.8 to 60 ng/mL. Trueness values, calculated as apparent recoveries, ranged from 70 to 135%. To correct for matrix effects, analyte concentrations in real urine were quantified by the standard addition method. To confirm the results obtained by guard column-MS/MS, an ultra(high)-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was also applied (total chromatographic run time 17 min, including column re-equilibration). Concentrations measured with both methods were in good agreement. Hence, we propose the use of guard column-MS/MS to analyse a large number samples in a very short time (semi-quantification), and apply the chromatographic analysis only to those samples with levels close to/higher than the concentrations equivalent to the safe maximum daily intakes of the parent compounds (confirmation). This double strategy (semi-quantification by guard column-MS/MS and confirmation-when needed-by UHPLC-MS/MS) implies important savings in time and money.

Development of a method for the determination of polyamines including N-acetylated forms in human saliva via benzoylation and gas chromatography-mass spectrometry

A simple method for the determination of polyamines and their N-acetylated forms was developed using benzoyl chloride as derivatization reagent, and 1,6-diaminohexane as internal standard, followed by liquid-liquid extraction with ethyl acetate. The organic extract was injected in a gas chromatograph using a programmed temperature vaporizer and the determination and quantification was performed with a quadrupole mass spectrometer. There was no matrix effect with the proposed method, so internal calibration was used to quantify the corresponding derivatives. Good linear responses were obtained in the range from the limits of detection to 500 µg L^-1 (50 µg L^-1 for spermidine), with correlation coefficients varying from 0.9591 to 0.9968. The limits of quantification (S/N = 10) ranged 1.0 - 8.3 µg L^-1. Recoveries were found between 82 - 117%, showing the good accuracy of the proposed method. Intra- and inter-day precision assays, expressed as relative standard deviation (RSD) were evaluated at two different concentration levels (low and high), showing values in the range of 2.4 - 6.1% and 5.2 - 9.0% for repeatability and reproducibility, respectively (6.9 - 9.7% and 14.1 - 14.6% for spermidine). Successful determination of the studied polyamines and their N-acetylated forms was performed on the saliva of 17 volunteers.

Polyamines of biological fluids of the body and the diagnostic value of their determination in clinical and laboratory researches (review of literature)

The review provides the analysis of the content of the main polyamines (PA) - spermine, spermidine and putrescine in the most important biological fluids of the human body (blood, urine, seminal fluid, etc.). The assessment of their diagnostic and prognostic value in clinical practice is carried out. The novelty and value of assessing of the level of PA metabolites as new diagnostic markers of various diseases has been shown. Among such diseases as cancer, stroke, renal failure, for which the search for early markers is especially relevant. This survey data can be of practical interest and taken into account in estimating the level of PA and its derivatives in clinical and laboratory reseaches. The literature search for the review was carried out using the Scopus, Web of Science, MedLine, RSCI databases.