PMID- 30586430
OWN - NLM
STAT- MEDLINE
DCOM- 20190514
LR  - 20200309
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 13
IP  - 12
DP  - 2018
TI  - Imaging and quantitative analysis of insecticide in mosquito net fibers using 
      Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS).
PG  - e0209119
LID - 10.1371/journal.pone.0209119 [doi]
LID - e0209119
AB  - Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis was used to 
      qualitatively and quantitatively assess the distribution of permethrin 
      insecticide on the surfaces and interiors of Olyset long-lasting insecticidal net 
      (LLIN) fibers. Total insecticide content in LLINs has been established using many 
      analytical methods. However, it is important to quantify the bioavailable portion 
      residing on the fiber surfaces for incorporated LLINs. ToF-SIMS is a very surface 
      sensitive technique and can directly image the spatial distribution of permethrin 
      insecticide on the surface of Olyset fibers. Surface permethrin appeared as 
      patchy deposits which were easily removed by acetone and reappeared after several 
      days as interior permethrin migrated (bloomed) from the fiber interior. After a 
      wash/incubation cycle, permethrin deposits were more diffuse and less 
      concentrated than those on the as-received fibers. ToF-SIMS is particularly 
      sensitive to detect the Cl- ion, which is the characteristic ion of permethrin. 
      Ion implantation and quantification of dopants using SIMS is well established in 
      the semiconductor industry. In this study, quantitative depth profiling was 
      carried out using 35Cl- ion implantation to correlate secondary ion yield with 
      permethrin concentration, yielding a limit of detection of 0.051 wt% for 
      permethrin. In some cases, surface concentration differed greatly from the fiber 
      interior (>1 mum below the surface). Two- and three-dimensional mapping of Cl at 
      sub-micrometer resolution showed permethrin to be dissolved throughout the fiber, 
      with about 2 vol% residing in disperse, high-concentration domains. This suggests 
      that these fibers fall into the class of monolithic sustained-release devices. It 
      is expected that ToF-SIMS can be a valuable tool to provide insight into the 
      insecticide release behavior of other LLIN products, both current and future.
FAU - Smith, Stephen C
AU  - Smith SC
AD  - Division of Parasitic Diseases and Malaria, Centers for Disease Control and 
      Prevention, Atlanta, Georgia, United States of America.
FAU - Zhou, Chuanzhen
AU  - Zhou C
AD  - Analytical Instrumentation Facility, North Carolina State University, Raleigh, 
      North Carolina, United States of America.
FAU - Stevie, Fred A
AU  - Stevie FA
AUID- ORCID: 0000-0002-1327-0304
AD  - Analytical Instrumentation Facility, North Carolina State University, Raleigh, 
      North Carolina, United States of America.
FAU - Garcia, Roberto
AU  - Garcia R
AD  - Analytical Instrumentation Facility, North Carolina State University, Raleigh, 
      North Carolina, United States of America.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
DEP - 20181226
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
RN  - 0 (Chlorides)
RN  - 0 (Insecticides)
RN  - 509F88P9SZ (Permethrin)
SB  - IM
MH  - Chlorides/chemistry
MH  - *Insecticide-Treated Bednets
MH  - Insecticides/*analysis
MH  - Microscopy, Electron, Scanning
MH  - Permethrin/analysis
MH  - Spectrometry, Mass, Secondary Ion
PMC - PMC6306175
COIS- The authors have declared that no competing interests exist.
EDAT- 2018/12/27 06:00
MHDA- 2019/05/15 06:00
PMCR- 2018/12/26
CRDT- 2018/12/27 06:00
PHST- 2018/09/12 00:00 [received]
PHST- 2018/11/28 00:00 [accepted]
PHST- 2018/12/27 06:00 [entrez]
PHST- 2018/12/27 06:00 [pubmed]
PHST- 2019/05/15 06:00 [medline]
PHST- 2018/12/26 00:00 [pmc-release]
AID - PONE-D-18-24662 [pii]
AID - 10.1371/journal.pone.0209119 [doi]
PST - epublish
SO  - PLoS One. 2018 Dec 26;13(12):e0209119. doi: 10.1371/journal.pone.0209119. 
      eCollection 2018.