Colorimetric determination of urea using diacetyl monoxime with strong acids

Urea is a byproduct of the urea cycle in metabolism and is excreted through urine and sweat. Ammonia, which is toxic at low levels, is converted to the safe storage form of urea, which represents the largest efflux of nitrogen from many organisms. Urea is an important nitrogen source in agriculture, is added to many industrial products, and is a large component in wastewater. The enzyme urease hydrolyzes urea to ammonia and bicarbonate. This reaction is microbially mediated in soils, hydroponic solutions, and wastewater recycling and is catalyzed in vivo in plants using native urease, making measurement of urea environmentally important. Both direct and indirect methods to measure urea exist. This protocol uses diacetyl monoxime to directly determine the concentration of urea in solution. The protocol provides repeatable results and stable reagents with good color stability and simple measurement techniques for use in any lab with a spectrophotometer. The reaction between diacetyl monoxime and urea in the presence of sulfuric acid, phosphoric acid, thiosemicarbazide, and ferric chloride produces a chromophore with a peak absorbance at 520 nm and a linear relationship between concentration and absorbance from 0.4 to 5.0 mM urea in this protocol. The lack of detectable interferences makes this protocol suitable for the determination of millimolar levels of urea in wastewater streams and hydroponic solutions.

Colorimetric determination of urea v2

This protocol measures the absorbance of urea in solution in complexation with diacetyl monoxime at 520 nm and is linearly proportional to concentration up to 5 mM urea.

The use of vitreous renal chemistries in the discrimination of postmortem fresh water drowning

Background: The World Health Organization (WHO) has estimated drowning as the leading cause of unintentional death in the world, with 372,000 deaths reported annually. Not all drowning are unintentional; some could be disguised to cover up an act of heinous criminality. This study was aimed at using some vitreous renal function biochemical parameters as a discriminant of postmortem fresh water drowning. Twelve albino rabbits constituted the sample size as validated by Mead’s formula. The study was divided into three groups; the control, postmortem-drowned and truly drowned as mimicked using an artificial fresh water pond. Vitreous humours were extracted using Coe method. The vitreous renal chemistries were analysed using diacetyl monoxime, Jaffe’s test, uricase and ion-selective electrode (ISE) methods respectively. Result: The mean of vitreous creatinine, urea, uric acid, Na+, K+, Cl−, Ca2+, glucose and CO2 of the control, postmortem-drowned and truly drowned groups were compared using One-way Anova (post-hoc-LSD) with the aid of SPSS Inc., Chicago, IL, USA; Version 18–21 package. The findings revealed a significant increase in concentrations of vitreous creatinine, glucose, Ca2+ and K+ of the drowned death group, whereas vitreous concentrations of CO2 and urea significantly decreased when compared to the controls and/or postmortem-drowned death. Conclusion: The study has shown that some of the studied vitreous biochemical parameters could be used as an ancillary tool in discriminating death due to fresh water drowning from that of disguised or postmortem-drowned death.

Microalbuminuria in Women with Risk Factors for Gestational Diabetes Mellitus in Some Selected Hospitals in Sokoto, Nigeria

Gestational diabetes mellitus (GDM) is a common metabolic abnormality which affects approximately 2-5% of pregnancies. Risk factors such as previous infants with macrosomia, strong family history of type 2 diabetes or GDM, poor glycaemic control and high pre-pregnancy body mass index (BMI) have been implicated in the development of GDM. This study was conducted to determine the prevalence of Microalbumnuria in women with risk factors for GDM and to estimate the levels of Urinary Microalbumin in these women. Fifty (50) pregnant women with risk factors for GDM and 50 controls (pregnant women without risk factors for GDM) were evaluated for Microalbuminuria. Microalbuminuria was estimated using Turbidimetric method, Random Plasma Glucose was estimated using Glucose oxidase method, serum Urea was estimated using Diacetyl Monoxime method, Creatinine was estimated using Jaffe Slot method and Albumin was estimated using Bromo Cresol Green method. The prevalence of Microalbuminuria in women with risk factors for GDM was 22%. Urinary microalbumin was significantly higher in the study subjects (56.36 ± 8.44 mg/L) than in the control (17.32 ± 4.5) mg/L. The mean ± standard error of mean of random plasma glucose in the study subjects was (5.84 ± 0.16) mmol/L and that of the control was (4.33 ± 0.14) mmol/L. The mean ± standard error of mean Serum Urea, Creatinine and Albumin were (4.1 ± 0.15) mmol/L, (0.70 ± 0.03) mg/dL, and (3.06 ± 0.05) g/dL respectively while that of the control was (3.47 ± 0.13) mmol/L, (0.63 ± 0.01) mg/dL and (2.78 ± 0.09) g/dL respectively. Obesity was strongly correlated to microalbuminuria.