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Design of a flow-through voltammetric sensor based on an antimony-modified silver electrode for determining lithol rubine B in cosmetics.

Lai-Hao W, Shu-Juan H - J Autom Methods Manag Chem (2011)

Bottom Line: For direct current (DC) mode, with the current at a constant potential, and measurements with suitable experimental parameters, a linear concentration from 0.125 to 1.80 μg/mL was found.The detection limit of our method was approximately 2.0 ng/mL.Findings using HPLC-ECD and HPLC with an ultraviolet detector were comparable.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Chemistry, Chia Nan University of Pharmacy and Science, 60 Erh-Jen Road, Section 1, Jen Te, Tainan 71743, Taiwan.

ABSTRACT
Lithol Rubine B (LRB; the disodium salt of 3-hydroxy-4-[(4-methyl-2-sulfophenyl) azo]-2-naphthalenecarboxylic acid) was detected using high-performance liquid chromatography with an electrochemical (antimony film on silver) detector (HPLC-ECD). For direct current (DC) mode, with the current at a constant potential, and measurements with suitable experimental parameters, a linear concentration from 0.125 to 1.80 μg/mL was found. The detection limit of our method was approximately 2.0 ng/mL. An antimony-modified silver detector was used to demonstrate that LRB is electrochemically reduced in acidic media and to analyze commercial cosmetics to determine their LRB content. Findings using HPLC-ECD and HPLC with an ultraviolet detector were comparable.

No MeSH data available.


Related in: MedlinePlus

Chromatograms for Lithol Rubine B from commercial lipstick at Sb/Ag electrode. Peaks 1, 0 mg/L lipstick added; 2, 0.150 mg/L lipstick added; 3, 0.300 mg/L lipstick added. Analysis conditions are identical to those listed in Figure 5.
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fig6: Chromatograms for Lithol Rubine B from commercial lipstick at Sb/Ag electrode. Peaks 1, 0 mg/L lipstick added; 2, 0.150 mg/L lipstick added; 3, 0.300 mg/L lipstick added. Analysis conditions are identical to those listed in Figure 5.

Mentions: The calibration plots obtained by plotting the peak area against the concentration of Lithol Rubine B show good linearity over the range 10–80 mg/L. The regression equations were y = 1.17x + 0.387 (correlation coefficient r = 0.9999); the range 0.30–1.2 mg/L and y = 202x + 10.0 (correlation coefficient r = 0.9999) for LC-UV and LC-ED, respectively (Figures 5(a) and 5(b)). Subsequently, we developed a simple and sensitive green electrochemical procedure for determining Lithol Rubine B in real samples. Commercial lipstick was spiked with 0.1, 0.2, or 0.3 mg/L and then analyzed. The calibration plot (Figure 6) shows good linearity. Because it is less expensive than LC-UV analysis, HPLC should be done using a conventional variable wavelength detector to achieve some selectivity and close to the optimum sensitivity of all the colorants. Thus, our proposed analytical method offers a valid and economical alternative to LC-UV detection of Lithol Rubine B.


Design of a flow-through voltammetric sensor based on an antimony-modified silver electrode for determining lithol rubine B in cosmetics.

Lai-Hao W, Shu-Juan H - J Autom Methods Manag Chem (2011)

Chromatograms for Lithol Rubine B from commercial lipstick at Sb/Ag electrode. Peaks 1, 0 mg/L lipstick added; 2, 0.150 mg/L lipstick added; 3, 0.300 mg/L lipstick added. Analysis conditions are identical to those listed in Figure 5.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig6: Chromatograms for Lithol Rubine B from commercial lipstick at Sb/Ag electrode. Peaks 1, 0 mg/L lipstick added; 2, 0.150 mg/L lipstick added; 3, 0.300 mg/L lipstick added. Analysis conditions are identical to those listed in Figure 5.
Mentions: The calibration plots obtained by plotting the peak area against the concentration of Lithol Rubine B show good linearity over the range 10–80 mg/L. The regression equations were y = 1.17x + 0.387 (correlation coefficient r = 0.9999); the range 0.30–1.2 mg/L and y = 202x + 10.0 (correlation coefficient r = 0.9999) for LC-UV and LC-ED, respectively (Figures 5(a) and 5(b)). Subsequently, we developed a simple and sensitive green electrochemical procedure for determining Lithol Rubine B in real samples. Commercial lipstick was spiked with 0.1, 0.2, or 0.3 mg/L and then analyzed. The calibration plot (Figure 6) shows good linearity. Because it is less expensive than LC-UV analysis, HPLC should be done using a conventional variable wavelength detector to achieve some selectivity and close to the optimum sensitivity of all the colorants. Thus, our proposed analytical method offers a valid and economical alternative to LC-UV detection of Lithol Rubine B.

Bottom Line: For direct current (DC) mode, with the current at a constant potential, and measurements with suitable experimental parameters, a linear concentration from 0.125 to 1.80 μg/mL was found.The detection limit of our method was approximately 2.0 ng/mL.Findings using HPLC-ECD and HPLC with an ultraviolet detector were comparable.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Chemistry, Chia Nan University of Pharmacy and Science, 60 Erh-Jen Road, Section 1, Jen Te, Tainan 71743, Taiwan.

ABSTRACT
Lithol Rubine B (LRB; the disodium salt of 3-hydroxy-4-[(4-methyl-2-sulfophenyl) azo]-2-naphthalenecarboxylic acid) was detected using high-performance liquid chromatography with an electrochemical (antimony film on silver) detector (HPLC-ECD). For direct current (DC) mode, with the current at a constant potential, and measurements with suitable experimental parameters, a linear concentration from 0.125 to 1.80 μg/mL was found. The detection limit of our method was approximately 2.0 ng/mL. An antimony-modified silver detector was used to demonstrate that LRB is electrochemically reduced in acidic media and to analyze commercial cosmetics to determine their LRB content. Findings using HPLC-ECD and HPLC with an ultraviolet detector were comparable.

No MeSH data available.


Related in: MedlinePlus