Elevated urinary cobalt concentrations identified in routine doping controls can originate from vitamin B12

Coordination chemistry applied to anti-doping analysis: Cobalt quantification as its diethyldithiocarbamate complex by liquid chromatography coupled to high resolution tandem mass spectrometry

Cobalt was included on the World Anti-Doping Agency Prohibited List in 2015 due to its effect on stimulus of erythropoiesis via stabilization of hypoxia-inducible factor. Although it has proven benefits for performance enhancement, the unavailability of inductively coupled plasma-mass spectrometry on routine of the accredited laboratories is a factor that reduces its applicability in anti-doping analysis. Therefore, an analytical method for quantification of urinary cobalt as its diethyldithiocarbamate complex by liquid chromatography coupled with high-resolution tandem mass spectrometry was developed and validated. Palladium was proposed as internal standard and rhodium as a complexation control. A microwave-assisted acid digestion of the urine samples was essential, not only to eliminate the matrix effect but mainly to avoid the non-specific bond of cobalt to endogenous molecules. A linear method was obtained over the studied range from a negative urine control to a spiked concentration of 25 ng/mL, with an estimated limit of quantification of 2.5 ng/mL, and an adequate combined standard uncertainty of 11.4%. Considering that all reagents are commercially available, the proposed strategy is feasible to be included on routine sample preparation. Monitoring urinary cobalt concentrations globally opens the perspective to support the anti-doping system to define a suitable threshold value and to understand its potential misuse by athletes seeking for performance improvement.

Association between urine cobalt and prevalence of kidney stones in Americans aged ≥ 20 years old

To determine whether urine cobalt (Co) is associated with the prevalence of kidney stones, we conducted a cross-sectional study of participants (≥ 20 years) involved in the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2018. The urine Co level was divided into four groups: 0.02-0.22, 0.22-0.36, 0.36-0.58, and 0.58-37.40 μg/L. The independent correlation between urine Co and prevalence of kidney stones was determined by logistic regression analyses. A total of 10,744 participants aged over 20 years that were not pregnant were eligible. Among them, 1041 participants reported ever having developed kidney stones. Patients with kidney stones developed significantly higher urine Co than the non-stone participants. The kidney stone patients were more likely to have been smoking ≥ 100 cigarettes in life; have hypertension, diabetes, and cancer; and engage in heavy activity. Multivariate logistic regression indicated a significantly positive relationship between the urine Co level and occurrence of kidney stones (OR 1.059, 95% CI 1.018-1.102, P = 0.00430). Moreover, the outcome remained unchanged after some sophisticated factors were adjusted (OR 1.059, 95% CI 1.001-1.120, P = 0.04635), and kidney stones were significantly related to a higher level of Co (OR (95% CI) = 0.22-0.36 μg/L: 1.111 (0.869, 1.421); 0.36-0.58 μg/L: 1.392 (1.095, 1.770); 0.58-37.40 μg/L: 1.712 (1.351, 2.170), and P for trend < 0.00001). So, urine Co concentration is positively associated with the prevalence of kidney stones. However, more high-quality prospective studies are needed to elucidate the causal correlation between Co level and kidney stones.

Quantification of cobalt and nickel in urine using inductively coupled plasma atomic emission spectroscopy

Cobalt and nickel are micronutrients indispensable for the body, therefore, their use with food or as part of vitamin complexes is necessary to maintain health. As a result, trace cobalt and nickel contents are present in human biological fluids - blood and urine. According to the World Anti-Doping Agency prohibited list, they belong to the group of blood doping preparations - erythropoiesis stimulants. Nowadays, methods for their control in biological fluids are being actively developed to establish reasonable allowable contents of these trace elements in human biological fluids. However, in addition to developing highly sensitive methods for the determination of the total content of cobalt and nickel using ICP-MS and ETAAS, the development and comparison of various sample preparation methods that can provide the greatest accuracy, reproducibility and express analysis are also relevant. In the present paper, a comparison of different sample preparation methods - direct analysis, dilution and microwave mineralization of urine samples was shown, the detection and quantification limits were compared, some metrological characteristics that can be achieved using these sample preparation methods were evaluated. The procedure was tested on artificial and real urine samples. Taking the course of vitamin complexes in therapeutic concentrations was shown not to lead to a significant increase in the concentrations of analytes in urine, while taking elevated concentrations (for example, 2-fold) makes it possible to determine them even using ICP-AES. However, even in this case, cobalt and nickel concentrations remain at a relatively low level, not able to lead to a significant increase in erythropoiesis.

Measurement of urinary cobalt as its complex with 2-(5-chloro-2-pyridylazo)-5-diethylaminophenol by liquid chromatography-tandem mass spectrometry for the purpose of anti-doping control

Cobalt is well known for its ability to stimulate erythropoiesis via stabilization of hypoxia-inducible factors. In sports, this can provide a competitive benefit to athletes, so the World Anti-Doping Agency prohibits the use of cobalt in any form except its cobalamin vitamers. As of now, cobalt in biological fluids is detected by inductively coupled plasma mass spectrometry (ICP-MS), a technique which has very limited availability in anti-doping laboratories. Therefore, a quantitative method based on liquid chromatography-tandem mass spectrometry capable of measuring urinary cobalt in the form of its complex with 2-(5-chloro-2-pyridylazo)-5-diethylaminophenol (5-Cl-PADAP) has been developed and validated. A cobalt complex with deuterium-labeled 5-Cl-PADAP was used as internal standard. The method was found linear over the concentration range of 5-500 ng/ml with a combined standard uncertainty less than 10% at 15, 200, and 450 ng/ml. Stability of cobalt ions in urine was investigated over the course of 2 months; the concentration of free Co²⁺ was observed to decline by approximately 50% but restored upon hydrolysis with hydrochloric acid. Unlike ICP-MS, this method is practically unaffected by the presence of cyanocobalamin as the latter is resistant to acid hydrolysis. Notwithstanding the lack of formalized threshold concentration of cobalt in urine, it is highly desirable that more anti-doping laboratories engage in testing for cobalt levels to better understand the prevalence of cobalt misuse in athletes. Given that cobalt salts are inexpensive and easily obtainable, the risk of such abuse should not be underestimated.

Annual banned-substance review: Analytical approaches in human sports drug testing 2019/2020

Analytical chemistry-based research in sports drug testing has been a dynamic endeavor for several decades, with technology-driven innovations continuously contributing to significant improvements in various regards including analytical sensitivity, comprehensiveness of target analytes, differentiation of natural/endogenous substances from structurally identical but synthetically derived compounds, assessment of alternative matrices for doping control purposes, and so forth. The resulting breadth of tools being investigated and developed by anti-doping researchers has allowed to substantially improve anti-doping programs and data interpretation in general. Additionally, these outcomes have been an extremely valuable pledge for routine doping controls during the unprecedented global health crisis that severely affected established sports drug testing strategies. In this edition of the annual banned-substance review, literature on recent developments in anti-doping published between October 2019 and September 2020 is summarized and discussed, particularly focusing on human doping controls and potential applications of new testing strategies to substances and methods of doping specified the World Anti-Doping Agency's 2020 Prohibited List.