Determination of Sudan IV in hot chilli powder with luminol/dissolved oxygen chemiluminescence system

Comparison of uric Acid quantity with different food in human urine by flow injection chemiluminescence analysis

Based on the inhibitory effect of uric acid (UA) on luminol-Co(2+) chemiluminescence (CL) system, a sensitive method for the determination of UA at nanomolar level by flow injection (FI) CL was proposed. The proposed method was successfully applied to real-time monitoring of UA excretion in human 24 h urine with different food intake, showing that meats, vegetables, and porridge intake caused differential UA excretions of 879, 798, and 742 mg, respectively. It was also found that UA concentrations in urine under the three kinds of food intake simultaneously reached maximum at 2 h after meals with the values of 417, 318, and 288 μg mL(-1), respectively. The UA concentration in human serum was also determined by this approach, and the possible mechanism of luminol-Co(2+)-UA CL reaction was discussed in detail.

A novel sensitive DNA-biosensor for detection of a carcinogen, Sudan II, using electrochemically treated pencil graphite electrode by voltammetric methods

A simple and inexpensive methodology was used to develop a novel electrochemical sensor for the determination of Sudan II. The interaction of Sudan II with salmon sperm ds-DNA on the surface of salmon sperm ds-DNA-modified pencil graphite electrode (PGE) and in solution phase was studied, using differential pulse voltammetry. The difference between adenine and guanine signals of the ds-DNA after and before interaction with Sudan II was directly proportional to Sudan II concentration, which used for quantitative inspections. Using PGE, a linear calibration curve (R(2)=0.9958) was observed with 0.5-6.0 μg mL(-1) Sudan II. Furthermore, the LOD of 0.4 μg mL(-1) and linear range between 0.5 and 4.0 μg mL(-1) were achieved in solution phase. In the second part, Sudan II was determined on a pretreated pencil graphite electrode by means of adsorptive stripping differential pulse voltammetry. The peak current was linearly dependent on Sudan II concentration over the range of 0.0015-0.30 μg mL(-1), with a detection limit of 0.00007 μg mL(-1) Sudan II. Both ds-DNA-modified PGE and PPGE were applied to analyze Sudan II in real samples.