Showing papers by "Lemmuel L. Tayo published in 2018"

Rapid microfluidic paper-based platform for low concentration formaldehyde detection

Abstract: An integrated platform consisting of a microfluidic paper-based analytical device (μPAD) and a portable detection system is proposed for low concentration formaldehyde (CH 2 O) detection. In the proposed approach, the reaction zone of the μPAD is coated with ammonium acetate (AA) and acetoacetanilide (AAA) indicator and is dried at 40 °C for 30 min. The formaldehyde sample is then dripped on the reaction zone and the μPAD is transferred to a hot plate in the portable detection system. A Hantzsch reaction is induced by heating the μPAD at 30 °C for 10 min. The resulting fluorescent formaldehyde-Acetoacetanilide complex (dihydropyridine derivative) is observed by a CMOS camera and the color image is transferred to a smartphone by means of a connector. Finally, the CH 2 O concentration is derived using self-written RGB color analysis mobile software implemented on the phone. The experimental results obtained using control samples with known CH 2 O concentrations in the range of 0.2–2.5 ppm show that the B (blue) fluorescence intensity (Y) and formaldehyde concentration (X) are related as Y = 29.455 X + 117.64. Moreover, the correlation coefficient is equal to R 2 = 0.9937. The real-world applicability of the proposed detection platform is demonstrated by measuring the CH 2 O concentration in twelve commercial food samples. It is shown that the concentration measurements obtained using the proposed system deviate by no more than 6.2% from those obtained using a conventional spectrophotometric technique. Overall, the results presented in this study show that the proposed integrated microfluidic paper-based system provides a compact and reliable tool for low concentration CH 2 O measurement purposes.

Association between Organochlorine Pesticide Levels in Breast Milk and Their Effects on Female Reproduction in a Taiwanese Population.

Abstract: Only few studies have focused on organochlorine pesticides (OCPs) in breast milk and the related health risks for women in Taiwan. Our goal is to examine breast milk OCPs and their associations with female reproductive function (infertility, gynecological diseases, and menstruation characteristics) as well as their correlation with sociodemographic parameters (age, pre-pregnant body mass index (BMI), annual incomes, population, birth year, and parity) and dietary habit. The breast milk samples were collected in southern Taiwan (n = 68) from 2013 to 2016 and the OCP residues were analyzed using high resolution gas chromatography with low resolution mass spectrometry (HRGC/LRMS). The results show that the most abundant OCP residues in the breast milk was ΣDDT with the geometric mean ± standard deviation of 9.81 ± 7.52 ng−1 lipid−1 followed by ΣHCH (0.539 ± 0.557 ng−1·lipid−1). In the principal component analysis, cis-chlordane (cis-CHL) and γ-HCH were found to be related to participants who received medical treatment for infertility, and 4,4′-DDT was associated with those who received gynecological surgery. The logistic regression showed that the odds ratio (OR) of log γ-hexachlorocyclohexane (γ-HCH) was higher for mothers who had received medical treatment for infertility than for the normal group (OR = 25.6, p = 0.035) after adjustments for age, pre-pregnant BMI, annual income, population (i.e., native-born Taiwanese), birth year, and parity. Cow milk and beef consumption as well as menstruation characteristics such as average menstrual period (>5 days), shortest menstrual period (<3 days), and women who had taken hormonal drugs were significantly associated to several OCP residues in the breast milk. In addition, ΣHCH including β-HCH and γ-HCH was correlated with annual family income and gravidity as well as cow milk and beef consumptions. Overall, γ-HCH exhibited a probable association with the infertility diseases of Taiwanese women, and dietary habit might play an important role in the female Taiwanese exposure to OCPs.

Levels of PCDD/Fs, PBDEs, and PBDD/Fs in Breast Milk from Southern Taiwan.

Abstract: This study investigates the congener-specific concentrations of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) in 25 breast milk samples from southern Taiwan. Most investigated congeners in Taiwanese breast milk are detectable except for PBDD/Fs. The geometric means of PCDD/Fs and PBDEs in the breast milk are 2.44 pg WHO2005-TEQ/g lipid and 2810 pg/g lipid. Several PCDD/F and PBDE congeners were highly correlated to each other like 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF (r = 0.919, p < 0.001). The longest duration of menstruation could be predicted by BDE-153 (β = 0.252) and 1,2,3,4,6,7,8-HpCDF (β = 0.345) with adjustment of confounders using a multiple stepwise linear regression model (r = 0.963, p < 0.001).

Levels of Non-PBDE Halogenated Fire Retardants and Brominated Dioxins and their Toxicological Effects in Indoor Environments - A Review

Abstract: Non-polybrominated diphenyl ether (non-PBDE) halogenated fire retardants (HFRs) such as new or novel brominated fire retardants (NBFRs) and dechlorane plus (DP) have been widely spread in the environment and recognized as emerging persistent organic pollutants (POPs) in the recent years, mainly due to the continuous increase in their global demand, especially after the worldwide restrictions on PBDE use. Polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) are the unintentional byproducts of PBDE commercial formulations in the indoor environment. Although HFRs, including NBFRs, DP, and PBDD/Fs, are ubiquitous in the indoor environment due to the large-volume release from the surfaces of consumer products, only a few in vitro and in vivo studies have addressed their toxic effects. In this review article, global data on NBFRs, including decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (BEH-TEBP), and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), DP, including syn-DP and anti-DP, and PBDD/Fs in indoor aerosol and dust are summarized from recent literature. Based on the gathered data, indoor dust is a major sink for indoor contamination and is of great concern due to the fact that dust ingestion is one of the primary routes for human exposure to these chemicals. Lastly, the toxic effects of NBFRs, DP, and PBDD/Fs identified in in vitro and in vivo studies are summarized and discussed based on the current published reports. However, there is still a lack of sufficient toxicity data for assessing their risks. Future works are encouraged to focus on indoor PM2.5-bound HFR levels to further evaluate their toxic effects on human health.