An MEKC method with LIF detection has been developed for the determination of seven neurotransmitter amino acids (NAAs) using 1,3,5,7-tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)difluoroboradiaza-S-indacene as the labeling reagent. After derivatization at room temperature for 30 min, the seven target NAAs including glycine, alanine, γ-aminobutyric acid, taurine, glutamine, glutamic acid, and aspartic acid were separated in running buffer, which consisted of 70 mM pH 4.00 H₃PO₄/Na₃PO₄ buffer, 5.5 mM cetyltrimethyl ammonium bromide and 20% v/v acetonitrile within 17 min. The LODs were 2 ∼ 14 × 10⁻¹⁰ M without interference from other coexisting amino acids. The proposed method has been applied to the analysis of NAAs in the central nervous systems of healthy mice and those with Alzheimer's disease with recoveries of 92–104%.

Altered levels of thiols in biological fluids are considered to be an important indicator for several diseases. In this article, 1,3,5,7-tetramethyl-8-bromomethyl-difluoroboradiaza-s-indacene is proposed as a fluorescent derivatization reagent for the determination of thiols including glutathione, cysteine, N-acetylcysteine, and homocysteine by HPLC. Under the optimized derivatization and separation conditions, a baseline separation of all the four derivatives has been achieved using isocratic elution on an RP C₈ column within 26 min. With fluorescence detection at 505 and 525 nm for the excitation and emission, respectively, the LODs (S/N = 3) are from 0.2 nM (glutathione) to 0.8 nM (cysteine). The feasibility of this method in real samples has been evaluated by the determination of thiols in human plasma from the healthy persons and hypertensive patients with recoveries of 92–105.3%.

A sensitive and effective micellar electrokinetic capillary chromatography with laser-induced fluorescence detection approach was described for the determination of low molecular-mass thiols using 1,3,5,7-tetramethyl-8-phenyl-(4-iodoacetamido) difluoroboradiaza-s-indacene as the labeling reagent. After precolumn derivatization, baseline separation of six thiol compounds including cysteine, glutathione, N-acetylcysteine, homocysteine, 6-mercaptopurine, and penicillamine were achieved within 18 min. The optimal running buffer was composed of mixtures involving 25 mM sodium dodecyl sulfate, 25% (v/v) acetonitrile and 15 mM sodium phosphate buffer, pH 7.5. The detection limits (S/N = 3) were found as low as 40 pM under argon ion laser-induced fluorescence detector (λ_ex/λ_em = 488/520 nm), which were much better than the reported approaches. The accuracy and specificity of this assay for real samples were assured by a standard addition method. The proposed method has been applied to the analysis of thiols both in human plasma and plum flower samples with recoveries of 92.0–109.4%.

Six phytohormones including indole butyric acid (IBA), naphthalene acetic acid (NAA), 2,4-dichloro-phenoxy acetic acid (2,4-D), indole-3-acetic acid (IAA), abscisic acid (ABA), and salicylic acid (SA) in crude plant extractions have been quantitated by means of high-performance liquid chromatography (HPLC) with fluorescence detection based on the precolumn derivatization using 1,3,5,7-tetramethyl-8-aminozide-difluoroboradiaza-s-indacene (BODIPY-aminozide), a fluorescent reagent synthesized in our lab recently. The optimization of derivatization conditions was carefully studied by an L₂₅ (5⁶) orthogonal array design (OAD) with five factors at five levels that are important influence parameters in the improvement of derivatization efficiency. The separation conditions were also studied in detail. Under the optimal conditions, the detection limits (S/N=3) of the six phytohormones were found from 0.12 to 0.75 nM. The proposed method was the first investigation of aminozide for the analysis of phytohormones and has been successfully applied to the determination of phytohormones in plant samples such as cucumber and tomato with recoveries of 94–105%.

A reversed-phase high-performance liquid chromatographic method based on chemical derivatization with fluorescence detection has been developed for analyzing biogenic amines in food and environmental samples. A BODIPY-based fluorescent reagent, 1,3,5,7-tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)-difluoroboradiaza-s-indacene (TMBB-Su), was employed for the derivatization of these biogenic amines at 20°C for 20 min in pH 7.20 borate buffer after careful investigation of the derivatization conditions including reagent concentration, buffer solution, reaction temperature and reaction time. Separation of biogenic amines with gradient elution was conducted on a C8 column with methanol–tetrahydrofuran–water as mobile phase. The detection limits were obtained in the range from 0.1 to 0.2 nM (signal-to-noise=3). This procedure has been validated using practical samples. The study results demonstrated a potential of employing high-performance liquid chromatography (HPLC) with 1,3,5,7-tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)-difluoroboradiaza-s-indacene labeling as a tool for quantitative analysis of biogenic amines involved in various matrices.

An HPLC method for the determination of biogenic amines based on the precolumn derivatization with N-hydroxysuccinimidyl fluorescein-O-acetate (SIFA) has been developed. The derivatization was performed at 45°C for 30 min in borate buffer (pH 8.0). The derivatives were separated on a ZORBAX Eclipse XDB-C8 column (150 mm×4.6 mm id; 5 μm) and monitored by fluorescence detection (excitation, 469 nm; emission, 512 nm). The LODs (S/N = 3) for spermine, spermidine, putrescine, cadaverine, and phenethylamine were 0.4, 0.2, 0.3, 0.5, and 0.4 nM, respectively. The developed method has been successfully applied to the determination of biogenic amines in human plasma of three healthy volunteers and four cancer patients. Average recoveries for plasma samples ranged from 94 to 106% and coefficients of variation ranged from 1.8 to 4.6%. Deproteinization of plasma was accomplished with ACN to precipitate interfering substances and the centrifuged supernatant was used directly for analysis.