Piezoelectric Crystal Liquid Flow Detection Systems Based on Alkyl (C18)-Benzo-15-Crown 5 for Organic Compounds and Metal Ions

Abstract

A wa ter in sol u ble long-chain crown ether alkyl (C18)-benzo-15-crown-5 was syn the sized and ap plied as a coat ing ma te rial on quartz crys tal mem branes of a liq uid flow pi ezo elec tric crys tal sen sor. The os cil lat ing crown ether-coated pi ezo elec tric (PZ) crys tal with a home-made com puter in ter face was pre pared as a liq uid chro mato graphic (LC) de tec tor for or ganic spe cies and metal ions in aque ous so lu tions. The os cil lat ing frequency of the quartz crys tal de creased due to the ad sorp tion of or ganic mol e cules or metal i ons on crown ether mol e cules. Ef fects of func tional group, mo lar mass, steric hin drance, and po lar ity of or ganic mol e cules on frequency re sponses of the crown ether coated PZ crys tal de tec tor were in ves ti gated. The fre quency re sponses of the crown ether coated PZ crys tal de tec tor for var i ous mol e cules were in the or der: amines > carboxylic ac ids > al co hols > ke tones. The crown ether PZ de tec tor also ex hib ited good sen si tiv ity for some heavy metal ions and the fre quency shifts were in the or der: Cr 3+ >> PbThe crown ether coated pi ezo elec tric crys tal LC de tec tor dem on strated low de tec tion lim its for var i ous po lar or ganic mol e cules, e.g., 6.0 × 10 -5 M for propylamine, and metal ions, e.g., 2.9 × 10 -5 M (1.8 ppm) for Cu 2+; the crown ether PZ de tec tor also gave good reproducibility when re used. A quite sen si tive elec tro chem i cal quartz crys tal microbalance (EQCM) de tec tion sys tem was also set-up for de tect ing trace heavy metal ions in so lu tions. The vari a tion in fre quency of the PZ crys tal and the dif fu sion cur rent were ob served si mul ta neously af ter the re duc tion in heavy metal ions such as Cu 2+ and Ni 2+ . The EQCM de tec tion sys tem ex hib ited fairly good sen si tiv ity, e.g., 112 Hz/ppm for Cu 2+ and a good de tec tion limit, e.g., 0.13 ppm for Cu 2+ ions. Com par i son be tween EQCM and PZ de tec tion sys tems was made and dis cussed.Key words: Crown ethers; Pi ezo elec tric liq uid chro mato graphic de tec tor; Or ganic mol e cules; Heavy metal ions; Elec tro chem i cal quartz crys tal microbalance. IN TRO DUC TIONPi ezo elec tric crys tals, e.g., quartz, BaTiO3, PZT (PbZrTiOx) and PLZT (PbLaZrOy), are well known to be sen si tive to pres sure on their sur face and have found widespread ap pli ca tions in com put ers, elec tronic equip ment, micro bal ances and com mu ni ca tion equip ment. The vi brational fre quency of an os cil lat ing pi ezo elec tric crys tal is decreased upon ad sorp tion of a for eign sub stance onto its surface. 1 The vari a tion in vi bra tional fre quency (∆F) re lated to the mass (Ms in g) of coat ing ma te ri als de pos ited on the crystal sur face of area A in cm2 and ba sic fre quency (Fo) of the pi ezo elec tric crys tal can be cal cu lated from Sauerbrey's equa tion [1]: ∆F = -2.3 × 10 6 × F o × (Ms/A). The the o ret i cal de tec tion limit of a 10 MHz os cil lat ing quartz crys tal can be es ti mated to be as small as 10 -12 g for...

A survey of the 2001 to 2005 quartz crystal microbalance biosensor literature: applications of acoustic physics to the analysis of biomolecular interactions

“…Other examples for small molecule detection, in particular environmental contaminants include petroleum hydrocarbons (Fahnrich et al, 2002;Applebee et al, 2004), Cr 6þ , Cr 3þ , Cd 3þ , Cu 2þ and other ions (Howie and Hoagland, 2002;Mirmohseni and Oladegaragoze, 2002;Tani and Umezawa, 2003;Sung and Shih, 2005), estrogenic compounds (Murata et al, 2003;Luck et al, 2004), aliphatic amines (Mirmohseni and Oladegaragoze, 2003), phenol (Mirmohseni and Oladegaragoze, 2004), sulfur dioxide (Palenzuela et al, 2005), NO x (Seh et al, 2005), enantiomers , pesticides , doxorubicin (Serpe et al, 2005), cholesterol (Ram et al, 2001), limonene (Fietzek et al, 2001), alcohols (Loergen et al, 2005), dioxins Kurosawa et al, 2003) and cisplatinum drugs .…”

Preparation and Application of Fullerene C60‐Polymers in Piezoelectric Quartz Crystal Sensors for Hemoglobin and Olefins

“…Piezoelectric crystals with appropriate coating adsorbents for a particular molecule can be applied as gas/liquid detectors. [17][18][19][20][21][22][23] In this study, the liquid Piezoelectric crystal sensor with C60-PCA coated crystals was developed to detect hemoglobin in water. In addition, a C60-PPA coated Piezoelectric crystal gas sensor was also prepared to detect the olefins such as 1-hexyne, 1-hexene, toluene and polycyclic aromatic hydrocarbons (PAHs).…”