Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 1034
Function: getPubMedXML
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3152
Function: GetPubMedArticleOutput_2016
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
A simple, low cost, fast and sensitive method is reported for the determination of the four endocrine disrupting chemicals (EDCs) 4-tert-butylphenol, 4-tert-octylphenol, bisphenol A and 17β-estradiol using pentafluoropyridine as the derivatizing reagent. These EDCs were determined by simultaneous extraction and derivatization in a solid phase analytical derivatization (SPAD) technique without the aid of any phase transfer catalyst (PTC) or an ion-pair mechanism. Recoveries of analytes as their tetrafluoropyridyl derivatives from water ranged from 71% for 4-tert-butylphenol to 106% for 17β-estradiol; from urine they ranged from 61% for 17β-estradiol to 91% for 4-tert-octylphenol; and from humic acids solution the ranged from 59% for 17β-estradiol to 104% for 4-tert-octylphenol in humic acid solutions. Calibration curves were constructed from a matrix of human male urine in the range 1-40 ng/mL and had coefficients of correlation greater than 0.99. For 4-tert-butylphenol, bisphenol A and 17β-estradiol the limits of quantitation were 5 ng/mL and for 4-tert-octylphenol it was 1 ng/mL. This method was applied to determine EDCs and detected 4-tert-octylphenol, bisphenol A and 17β-estradiol in concentrations comparable to those found in the literature. The method offers advantages in speed of analysis, reduced reagent and specificity of derivatization.
Download full-text PDF |
Source |
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http://dx.doi.org/10.1016/j.chroma.2011.10.060 | DOI Listing |
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