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: 3122
Function: getPubMedXML
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
The present study proposes an analytical methodology that employs ion chromatography-conductivity detection for simultaneous quantification of inorganic (F(-), Cl(-), NO(3)(-), SO(4)(2-), and PO(3)(-)), monocarboxylate (HCOO(-), CH(3)COO(-), propionate, n-butyrate, lactate, and pyruvate), dicarboxylate (oxalate and succinate), and tricarboxylate anions (citrate), as well as crustal cations (Li(+), Na(+), K(+), NH(4)(+), Ca(2+), Mg(2+)) at low pgm(-3) range in airborne particle samples in one single run. The optimized conditions for anions were as follows: 0.6 mmol L(-1) KOH for 0-14 min, 0.6-15 mmol L(-1) KOH 14-20 min, 15-38 mmol L(-1) KOH during 20-32 min and finally returned to 0.6 mmol L(-1) for a period of 3 min, thereafter the eluent flow rate was 0.38 mL min(-1). Similarly, for cations, isocratic elution was adjusted to 0.36 mL min(-1) at 17.5 mmol L(-1) H(2)SO(4). LOD ranged 3.0-130 pgm(-3) and LOQ was within 10-400 pgm(-3) (Li(+) and PO(4)(3-), respectively) as well as recoveries ranged 89% (Ca(2+)) to 120% (Li(+)). Major ions were successfully determined in real PM1 and PM2.5 samples. The method used here was found to be a comprehensive, simple, cheap and reliable procedure for studying ions in particulate matter (PM) samples even those from remote areas or near ecosystem natural conditions.
Download full-text PDF |
Source |
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http://dx.doi.org/10.1016/j.chroma.2012.08.074 | DOI Listing |
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