Open Access Short Research Article

Development and Validation of Colorimetric and RP-HPLC Methods for the Determination of Formaldehyde in Cosmetics

Md. Motiur Rahman, Harun- or-Rashid, Subrata Bhadra, A. S. Shamsur Rouf

Chemical Science International Journal, Page 224-237
DOI: 10.9734/ACSJ/2015/12385

Aims: To develop and validate two assay methods for the determination of total and free formaldehyde content in cosmetics by Colorimetric and High Performance Liquid Chromatographic (HPLC) methods, respectively.

Study Design: Colorimetric and HPLC methods.

Place and Duration of Study: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Dhaka, Dhaka-1000, Bangladesh; between February 2012 and June 2013.

Methodology: In Colorimetric method the quantitation was performed by a UV/Vis spectrophotometer at 410 nm and by HPLC at 345 nm and the methods were linear over the concentration ranges of 4-12 mg/L (R2=0.999) and 2-32 mg/L (R2=0.999), respectively. Based on 2, 4-dinitrophenylhydrazine (DNPH) derivatization, free formaldehyde was analyzed using a Phenomenex C18 (250 mm × 4.6 mm i. d., 5 μm particle size) column in a binary separation mode with mobile phase consisting of acetonitrile and distilled water (45:55, v/v) and flow rate of 2.0 mL/min.

Results: The overall recovery rate of free formaldehyde was (95.33-98.37)±(0.29-1.6)% (RSD). Seventy five cosmetics of local and foreign brands were investigated. None of those products was labeled to contain formaldehyde. 18 products were labeled with specific formaldehyde donors (17 with DMDM hydantoin and 1 with imidazolidinyl urea). 64% of the products were formaldehyde positive among which 54% exceeded 0.05% limit of formaldehyde content for which EU dictates the mandatory formaldehyde donors labeling. The investigated amounts of the total formaldehyde and free formaldehyde were 190-5502 mg/L and 47-604 mg/L, respectively.

Conclusion: The methods were found valid as per in terms of suitability, linearity, accuracy, sensitivity, ruggedness, and robustness. The formaldehyde content found in the cosmetics was highly alarming and must be addressed by the authority in an immediate basis.


Open Access Original Research Article

Infrared Spectra of NH4+ ions Matrix-Isolated in Tutton Compounds M'2M''(XO4)2∙6H2O (M' = Rb, Cs; M'' = Mg, Co, Zn; X = S, Se)

V. Karadjova

Chemical Science International Journal, Page 202-213
DOI: 10.9734/ACSJ/2015/12307

Infrared spectra of ammonium doped rubidium and cesium sulfate and selenate matrices, M'2M''(XO4)2∙6H2O (M' = Rb, Cs; M'' = Mg, Co, Zn; X = S, Se), are presented and discussed in the region of  both the asymmetric bending modes n4 of the ammonium ions and the water librations. The ammonium ions included in the sulfate matrices display three bands corresponding to n4 in agreement with the low site symmetry C1 of the host cations, while those included in the selenate matrices exhibit four bands for n4. A hypothesis is made that the reason for this phenomenon is the formation of polyfurcate hydrogen bonds between the ammonium guest ions and the selenate host ions, thus leading probably to a disorder of the ammonium ions. The degree of energetic distortion of the ammonium ions with respect to the bond angles H−N−N as deduced from the values of Dn4/nc depends on the repulsion potential of the matrices and the strength of the hydrogen bonds. The strength of the hydrogen bonds formed in the rubidium and cesium salts containing isomorphously included ammonium ions as deduced from the wave numbers of the water librations is discussed. The analysis of the spectra reveals that weaker hydrogen bonds are formed in the mixed crystals M'1.85(NH4)0.15M''(XO4)2·6H2O (M' = Rb, Cs; M'' = Mg, Co, Zn; X = S, Se) as compared to those formed in the neat rubidium and cesium compounds. These spectroscopic findings are owing to the decrease in the proton acceptor strength of the SO42- and SeO42- ions as a result of the formation of hydrogen bonds between the host anions and the ammonium guest cations (anti-cooperative or proton acceptor competitive effect).


Open Access Original Research Article

Batch and Flow Injection Analysis Spectrophotometric Determination of Amoxicillin using N-bromosuccinimide and Indigo Carmine

Bery M. Rahman, Kamal M. Mahmoud

Chemical Science International Journal, Page 214-223
DOI: 10.9734/ACSJ/2015/13150

This paper describes a batch(direct spectrophotometer) and flow injection spectrophotometric for indirect determination of amoxicillin (AMX). The method involves addition of a known excess of N-bromosuccinimde (NBS) to AMX in acidic medium, the residual amount of oxidant (NBS) reacted with indigo carmine which causes bleaching of its blue color. The absorbance was measured at 610 nm. In the batch method Beer’s law was obeyed in the concentration range (0.2 - 6.0 μg ml-1) and detection limit of 0.1 μg ml-1with a correlation coefficient (r) of 0.9945 and a molar absorptivity of 3.874x104L mol-1cm-1. A simple FI-spectrophotometric system was applied for determination of AMX depending on the batch method. A calibration graph gives linear range of (2.0 - 14.0 μg ml-1) AMX, with a detection limit of 1.8 μg ml-1, a correlation coefficient (r) of 0.9965 and a sampling frequency of 48 S h-1. Essential parameters such as accuracy and precision were studied for the two methods by calculation of (RSD %) and (E%) for two different levels of concentration. The method was relatively free from common excipients and it is applied successfully for the determination of AMX in pharmaceutical formulations.

Open Access Original Research Article

Speciation of Some Heavy Metals in Sediments of the Pennington River, Bayelsa State, Nigeria

Leizou Kaywood Elijah, Horsfall Michael Junior, Spiff Ayebaemi Ibuteme

Chemical Science International Journal, Page 238-246
DOI: 10.9734/ACSJ/2015/14696

The total heavy metal concentrations of some environmentally toxic metals in sediments of the Pennington River System, Bayelsa state, Nigeria was examined. The concentrations of heavy metals in each fraction were determined using a ANALYST 400 Perkin-Elmer AAS. The mean concentrations (mg/kg) for the six metals in dry season sediment samples were: 0.14±0.17(As), 0.39±0.55(Co), 2.43±5.06(Cu), 26.82±22.19(Fe), 0.69±1.10(Pb), and 1.22±1.19(Zn), while the mean metal concentrations (mg/kg) in wet season samples were:0.11±0.18(As),0.37±0.6(Co), 2.07±4.35(Cu), 26.65±24.79(Fe), 0.61±1.08(Pb), and 1.11±1.00(Zn) respectively. Speciation study applying the five-stage sequential extraction scheme revealed that As, Co, and Pb in sediment prevails mostly in exchangeable fraction. Cu and Zn were more prevalent in residual fraction, while Fe was found more in residual and Fe/Mn-Oxide fractions. In an attempt to infer anthropogenic input from natural input, comparison with sediment quality guideline (SQGs) and ecotoxicological sense of heavy metal contamination was employed. The concentration of the studied heavy metals in Pennington River System does not pose a threat to the sediment dwelling fauna and anyone who consumes aquatic animals, particularly fish, from the Pennington River. According to SQGs, the studied heavy metals of the Pennington River sediments were under the category of non-polluted.

Open Access Original Research Article

Determination and Comparison of Physico-chemical Properties of Home-made Juices in Lesotho and Commercial Juice Available in the Local Markets

Mosotho J. George, Limpho V. Moiloa

Chemical Science International Journal, Page 247-252
DOI: 10.9734/ACSJ/2015/14943

The study was carried out to investigate the comparative nutritional value and physicochemical properties of home-made apple juice and mixed fruit juice (apple, banana and pear) with commercial 100% apple juice. The principal component analysis model revealed the complete difference between these juices with major source of difference being moisture, ash and ascorbic acid contents. Ascorbic acid was found to be lower in home-made juices (1.6±0.01, 1.78±0.79g/100ml) as compared to the commercial juice (3.41±0.76g/100ml), ash content ranged between 1.94±0.06, 0.19±0.02 and 1.97±0.76%, for home-made apple juice, mixed fruit juice and commercial juice respectively. Moisture content was comparatively higher in commercial juice (87.8±0.03%) than in home-made apple juice and mixed fruit juice (84.3±0.2 and 84.4±0.07). The nutritional value of home-made apple juice did not differ significantly (p=0.5) from that of commercial juice.




Open Access Original Research Article

Adsorption Isotherm Studies of Cd(ll) and Pb(ll) Ions from Aqueous Solutions by Bamboo-Based Activated Charcoal and Bamboo Dust

Stevens A. Odoemelam, Francis K. Onwu, Sonde C. Uchechukwu, Mgbeahuruike A. Chinedu

Chemical Science International Journal, Page 253-269
DOI: 10.9734/ACSJ/2015/14425

This study investigates a comparative assessment of two adsorbents: Bamboo-based Activated Charcoal (BBAC) and Bamboo dust (BD) in the removal of lead(ll) and cadmium(ll) ions from aqueous solutions. Maximum Pb(II) and Cd(II) removal was observed at pH 6.0. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models were applied to the adsorption data. The coefficients of determination of the four models were high with Freundlich model providing the best description for the experimental adsorption data. The fitting of the adsorption data into Freundlich model shows that the mode of adsorption of the metal ions by both adsorbents follows physisorption. Investigation into the maximum adsorption capacity showed that Pb(ll) was better adsorbed than Cd(ll) on both adsorbents. Maximum adsorption capacities corresponding to monolayer coverage, obtained from the Langmuir plots were 4.792 mg g-1 and 4.594 mg g-1 respectively for Pb(ll) and Cd(ll) ions onto the BBAC and 4.771 mg g-1 and 4.400 mg g-1 for their adsorption onto BD. The Langmuir adsorption coefficient, KL which is related to the affinity of the adsorbents for the metal ions were 0.699 and 0.271 respectively for adsorption of Pb(II) and Cd(II) ions onto BBAC and 0.299 and 0.226 for adsorption onto BD following the initial order. The carbonized bamboo based adsorbent was generally found to have an increased adsorption capacity for the metal ions than bamboo dust.