Method For Determination Of Bilirubin Research Articles

A comprehensive review of bilirubin determination methods with special emphasis on biosensors

Abstract Bilirubin, is a tetrapyrrole yellow coloured compound found in digestive juice. It is generated from degradation of hemoglobin (Hb). The normal range of total bilirubin in serum is 0.30–1.20 mg/dl. The elevated range of serum bilirubin is considered as biomarker for finding and therapeutic administration of many liver diseases. Various analytical methods for determination of bilirubin, including spectrophotometery, thin layer chromatography, fluorometry, capillary electrophoresis, high performance liquid chromatographic, polarography and chemiluminescence have been applied for clinical purposes. These conventional methods are tedious, time-consuming, and require costly equipments and skilled person to operate. To overcome these limitations, the most popular biosensing technology has been employed at a large scale. The present review describes the principle, advantages and disadvantages of different analytic methods for measurement of bilirubin with focusing on biosensors, including electrochemical, photo-electrochemical, piezoelectric, optical and luminescent biosensors in detail. The working conditions for optimum activity and shelf life of all bilirubin biosensors have been summarized & compared and their future perspectives are discussed.

Alternative spectrophotometric method for determination of bilirubin and urobilinogen in urine samples using simultaneous injection effective mixing flow analysis

A new approach based on simultaneous injection effective mixing flow analysis (SIEMA) system was developed for the successive spectrophotometric determination of urobilinogen and bilirubin in urinary samples. A 4-channel SIEMA system consisted of a syringe pump, two 5-cross connectors, four holding coils (two of four were used for urobilinogen determination, and other two of four were used for bilirubin determination), five solenoid valves, a mixing coil and a spectrophotometer. For urobilinogen assay, the color development was based on the reaction with p-diethylaminobenzaldehyde (p-DEABA) in the presence of strong hydrochloric acid. On the other hand, bilirubin was measured by the reaction with diazotized sulfanilic acid in the presence of n-octyl-β-D-thioglucoside (OTG) which served as a solubilizing agent to form OTG–azobilirubin. Firstly for bilirubin determination, aliquots of sample and reagent solutions were aspirated into two individual holding coils by a syringe pump, and then the aspirated zones were simultaneously dispensed in the reverse direction to the detector flow cell. Secondary for urobilinogen determination, aliquots of sample and reagent for urobilinogen were aspirated into other two holding coils, followed by the similar spectrophotometric detection. Under optimal conditions, the automated method provided linearity up to 100.0 mg L−1 for urobilinogen and 5.0 mg L−1 for bilirubin. The 3σ limit of detections (LODs) for urobilinogen and bilirubin were 1.0 mg L−1 and 0.003 mg L−1, respectively. The relative standard deviations (RSDs, n = 11) of 30 mg L−1 urobilinogen and 1.0 mg L−1 for bilirubin were 1.5% and 1.0%, respectively. Sample throughput of the whole assay of both urobilinogen and bilirubin was 30 h−1. The proposed method can be applied to trace urobilinogen and bilirubin in urine samples and the results are useful for screening diabetic diagnostic.

Use of the caffeine reagent in direct spectrophotometry of bilirubin.

The molar absorptivity of unconjugated bilirubin in caffeine reagent is independent of the protein matrix. This finding, together with the simplicity of a dilution step for direct spectrophotometry, will improve the calibration methods of bilirubin and make them more nearly accurate. This is encouraging for the development of a new method for bilirubin determination in neonates; moreover, the caffeine reagent has a clearing influence on the turbidity of human sera. These findings should also be important for standardization, especially because the method of Jendrassik and Gróf is also protein-independent. Therefore, the introduction of one reliable, inexpensive, "universal" standard of bilirubin in bovine serum albumin will be of importance for both methods.

A candidate reference method for determination of bilirubin in serum. Test for transferability.

A candidate reference method for determination of bilirubin in serum. Test for transferability.

Derivative Spectrophotometry: Determination of Bilirubin in Amniotic Fluid

Abstract Spectrophotometric analysis presents very often the disadvantage of interferences by substances which can absorb near the substance of interest. The use of derivative spectra allows to overcome this difficulty. In this paper we describe a method for determination of bilirubin in amniotic fluid based on use of derivative spectrophotometry. This method presents some advantages of accuracy and quickness in comparison with the ones normally used.