RESUMO
Graphitized carbon black (GCB) in the traditional QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used to remove the interfering substance chlorophyll in vegetable and fruit samples for pesticide residues determination. However, it not only adsorbs pigments, but also adsorbs some planar and aromatic pesticides. In order to solve the shortcoming, a core-shell magnetic molecularly imprinted polymer (Fe3O4@MIP) that can specifically recognize and adsorb chlorophyll was synthesized, and an advanced QuEChERS method with the Fe3O4@MIP as a purification material was developed. This advanced method presents detection that is highly sensitive, specific, and reproducible for planar and aromatic pesticides. The limits of detection (LOD) ranged from 0.001-0.002 mg kg-1, and the limit of quantification (LOQ) was 0.005 mg kg-1. The recovery for the planar and aromatic pesticides was within 70-110% with the associated relative standard deviations < 15% in leek samples by the advanced QuEChERS method. However, in the traditional QuEChERS method with GCB, the recovery of most planar and aromatic pesticides was <60%. It may also be useful for the determination of other pesticides in vegetable samples with quick and easy sample purification.
RESUMO
The aim of this study was to assess the relationships between transforming growth factor ß1-509C/T (rs1800469) and +869T/C (rs1800470) polymorphisms and the risk of upper digestive tract cancer (UDT cancer) by using a meta-analysis. We interrogated the databases of Medline, Embase and Wanfang (Chinese literature database) (latest update; December 15, 2011). Odds ratios (OR) and corresponding 95% confidence intervals (95% CI) were used to assess the strength of the associations. In total, 20 case-control studies were included in this meta-analysis. Overall, both TGF ß1-509C/T and +869T/C polymorphisms were not associated with risk of UDT cancer [-509C/T: OR (95%CI) = 1.10 (0.99-1.22) for TT vs. C carries, P(heterogeneity) = 0.10; +869T/C: OR (95%CI) = 1.04 (0.88-1.23) for CC vs. T carriers, P(heterogeneity) = 0.02]. Subgroup analyses indicated that the -509T allele was associated with increased risk of UDT cancer in population-based studies (OR = 1.16 (1.04-1.31), P(heterogeneity) = 0.31 for TT vs. C carriers) and in small sample-sized studies (OR = 1.45 (1.15-1.84), P(heterogeneity) = 0.56 TT vs. C carriers). All subgroup analyses for the TGF ß1+869T/C polymorphism indicated null association except for hepatocellular carcinoma. Interestingly, both the TGF ß1-509T allele and the +869C allele were associated with decreased risk of hepatocellular cancer based on limited original studies. This meta-analysis indicated that TGF ß1-509C/T rather than +869T/C is a potential risk factor for UDT cancer.