View source for Solid-phase microextraction

[[File:Spme02.png|thumb|400 px|Solid-phase microextraction sampling]]
'''Solid phase microextraction''', or '''SPME''', is a [[solid phase extraction]] sampling technique that involves the use of a fiber coated with an extracting phase, that can be a liquid ([[polymer]]) or a solid ([[sorbent]]),<ref name="SpietelunPilarczyk2010">{{cite journal|last1=Spietelun|first1=Agata|last2=Pilarczyk|first2=Michał|last3=Kloskowski|first3=Adam|last4=Namieśnik|first4=Jacek|title=Current trends in solid-phase microextraction (SPME) fibre coatings|journal=Chemical Society Reviews|volume=39|issue=11|year=2010|pages=4524–37 |doi=10.1039/c003335a|pmid=20882243}}</ref> which extracts different kinds of [[analyte]]s (including both [[Volatility (chemistry)|volatile]] and non-volatile) from different kinds of media, that can be in liquid or gas phase.<ref>{{cite book |doi=10.1002/0471457817 |page=113 |title=Sample Preparation Techniques in Analytical Chemistry |date=2003 |isbn=978-0-471-32845-2 |editor-last1=Mitra |editor-first1=Somenath }}</ref> The quantity of analyte extracted by the fibre is proportional to its concentration in the sample as long as [[Chemical equilibrium|equilibrium]] is reached or, in case of short time pre-equilibrium, with help of [[convection]] or agitation.

==Analysis==
After extraction, the SPME fiber is transferred to the injection port of separating instruments, such as a [[gas chromatography]] and [[mass spectrometry]],<ref name="VasVékey2004">{{cite journal|last1=Vas|first1=György|last2=Vékey|first2=Károly|title=Solid-phase microextraction: a powerful sample preparation tool prior to mass spectrometric analysis|journal=Journal of Mass Spectrometry|volume=39|issue=3|year=2004|pages=233–254 |doi=10.1002/jms.606|pmid=15039931|bibcode=2004JMSp...39..233V}}</ref> where [[desorption]] of the analyte takes place and analysis is carried out.

==Advantages==
The attraction of SPME is that the extraction is fast, simple, can be done usually without solvents, and detection limits can reach parts per trillion (ppt) levels for certain compounds.  SPME also has great potential for field applications; on-site sampling can be done even by nonscientists without the need to have gas chromatography-mass spectrometry equipment at each location.  When properly stored, samples can be analyzed days later in the laboratory without significant loss of volatiles.<ref name="Verma et al Solid-phase microextraction"/>

== Fiber Coatings ==
The coating on the SPME fiber can be selected to improve sensitivity for specific analytes of interest; ideally the sorbent layer will have a high affinity for the target analytes.<ref name=":0">{{Cite journal|last1=Spietelun|first1=Agata|last2=Pilarczyk|first2=Michał|last3=Kloskowski|first3=Adam|last4=Namieśnik|first4=Jacek|date=2010|title=Current trends in solid-phase microextraction (SPME) fibre coatings|journal=Chemical Society Reviews|language=en|volume=39|issue=11|pages=4524–4537|doi=10.1039/c003335a|pmid=20882243 }}</ref><ref name=":2">{{Cite journal|last1=Spietelun|first1=Agata|last2=Kloskowski|first2=Adam|last3=Chrzanowski|first3=Wojciech|last4=Namieśnik|first4=Jacek|date=2012-12-28|title=Understanding Solid-Phase Microextraction: Key Factors Influencing the Extraction Process and Trends in Improving the Technique|journal=Chemical Reviews|language=EN|volume=113|issue=3|pages=1667–1685|doi=10.1021/cr300148j|pmid=23273266 }}</ref> There are many commercially available SPME fiber coatings that are combinations of [[polydimethylsiloxane]], [[divinylbenzene]], Carboxen, [[polyacrylate]], and [[polyethylene glycol]].<ref name=":1">{{Cite journal|last1=Reyes-Garcés|first1=Nathaly|last2=Gionfriddo|first2=Emanuela|last3=Gómez-Ríos|first3=German Augusto|last4=Alam|first4=Md. Nazmul|last5=Boyacı|first5=Ezel|last6=Bojko|first6=Barbara|last7=Singh|first7=Varoon|last8=Grandy|first8=Jonathan|last9=Pawliszyn|first9=Janusz|date=2017-12-14|title=Advances in Solid Phase Microextraction and Perspective on Future Directions|journal=Analytical Chemistry |volume=90|issue=1|pages=302–360|doi=10.1021/acs.analchem.7b04502|pmid=29116756 |doi-access=free}}</ref><ref>{{Cite journal|last1=Kumar|first1=Ashwini|last2=Gaurav|last3=Malik|first3=Ashok Kumar|last4=Tewary|first4=Dhananjay Kumar|last5=Singh|first5=Baldev|date=2008-03-03|title=A review on development of solid phase microextraction fibers by sol–gel methods and their applications|journal=Analytica Chimica Acta|volume=610|issue=1|pages=1–14|doi=10.1016/j.aca.2008.01.028|pmid=18267134|bibcode=2008AcAC..610....1K }}</ref> However, one downside to many of the commercially available SPME fibers is that they tend to be physically brittle due to their composition.<ref name=":2" /> Depending on the characteristics of the target analytes, certain properties of the coating improve extraction such as polarity, thickness, and surface area.<ref name=":0" /><ref>{{cite journal |last1=Wardencki |first1=Waldemar |last2=Michulec |first2=Magdalena |last3=Curyło |first3=Janusz |title=A review of theoretical and practical aspects of solid‐phase microextraction in food analysis |journal=International Journal of Food Science & Technology |date=August 2004 |volume=39 |issue=7 |pages=703–717 |doi=10.1111/j.1365-2621.2004.00839.x }}</ref> The sample matrix can also influence the fiber coating selection. Based on the sample and analytes of interest, the fiber may need to tolerate direct immersion as opposed to a [[Headspace technology|headspace]] extraction.<ref name=":1" /> In one of the  study the fiber coating method significantly enhances the performance of SPME by ensuring a high binding capacity and improved mass transfer efficiency. By preventing the ingress of the polymeric adhesive matrix into the pores of the sorbent particles, the method allows for faster adsorption and desorption times, which is crucial for high-throughput applications.<ref>{{Cite patent|number=US20200261887A1|title=Improvements in Solid Phase Micro-Extraction Substrate Coatings|gdate=2020-08-20|invent1=Wirth|invent2=Verma|inventor1-first=Hans-Jürgen|inventor2-first=Neeraj|url=https://patents.google.com/patent/US20200261887A1/en}}</ref>

== Application of SPME in Forensic Science ==
SPME has become an essential technique in forensic science, particularly for analyzing complex matrices such as blood, urine, and environmental samples. Its advantages include the ability to perform rapid and sensitive extractions without the need for extensive sample preparation, which is crucial in forensic investigations where sample integrity is paramount. For instance, SPME has been successfully employed to detect drugs of abuse, explosives, and other volatile compounds from various samples, allowing for the efficient identification of substances relevant to criminal cases. The automation and miniaturization of SPME techniques further enhance their applicability in forensic settings, enabling high-throughput analysis and reducing the risk of contamination.<ref name="Verma et al Solid-phase microextraction"/>

== Green Sample Preparation ==
SPME is recognized as a green analytical method for sample preparation, particularly in forensic drug analysis. This technique offers several advantages over traditional methods like liquid-liquid extraction (LLE) and solid-phase extraction (SPE), including automation, rapid sample processing, and reduced solvent usage. SPME allows for the extraction of analytes directly from complex matrices, such as biological and environmental samples, while minimizing the environmental impact associated with conventional extraction techniques.<ref name="Verma et al Solid-phase microextraction"/><ref>{{cite journal |last1=López-Lorente |first1=Ángela I. |last2=Pena-Pereira |first2=Francisco |last3=Pedersen-Bjergaard |first3=Stig |last4=Zuin |first4=Vânia G. |last5=Ozkan |first5=Sibel A. |last6=Psillakis |first6=Elefteria |title=The ten principles of green sample preparation |journal=TrAC Trends in Analytical Chemistry |date=March 2022 |volume=148 |pages=116530 |doi=10.1016/j.trac.2022.116530 |hdl=10852/100181 |hdl-access=free }}</ref>
[[File:Ten principles of green sample preparation..tif|thumb|'''Ten principles of green sample preparation.'''<ref name="Verma et al Solid-phase microextraction">{{cite book |doi=10.1016/b978-0-443-13907-9.00005-x |chapter=Solid-phase microextraction |title=Green Analytical Methods and Miniaturized Sample Preparation techniques for Forensic Drug Analysis |date=2025 |last1=Verma |first1=Neeraj |last2=Arya |first2=Nikhilesh |last3=Singh |first3=Varoon |pages=79–112 |isbn=978-0-443-13907-9 }}</ref>|alt=Ten principles of green sample preparation. |center]]

==References==
{{reflist}}

==Further reading==
* {{cite book |doi=10.1016/C2022-0-02711-2 |title=Green Analytical Methods and Miniaturized Sample Preparation techniques for Forensic Drug Analysis |date=2025 |isbn=978-0-443-13907-9 }}
* [[Janusz Pawliszyn]]: Handbook of Solid Phase Microextraction, Chemical Industry Press, 2009.
* Pawliszyn J.: Solid Phase Microextraction: Theory and Practice, Wiley-VCH, 1997.
* Pawliszyn J.: Applications of Solid Phase Microextraction, Royal Society of Chemistry, 1999.

== Interactive lectures ==

* [http://ecobio.cfhma.kz/spme/story.html Introduction to Solid Phase Microextraction]
* [http://ecobio.cfhma.kz/spmequant/story.html Quantification using Solid Phase Microextraction]
{{DEFAULTSORT:Solid Phase Microextraction}}
[[Category:Laboratory techniques]]