Investigation on the Decomposition of Carboplatin in Infusion Solutions

 An integrated solid-phase spectrophotometry/flow injection analysis (FIA) method is proposed for the determination of the synthetic colorant matter Ponceau 4R (P4R) in the presence of its unsulfonated derivative 2-hydroxy-1-[(naphthalenyl)azo] naphthalene (N2N). The procedure is based on the measurement of P4R at λ = 508, followed by retention and preconcentration of the low level concentration of N2N on a C₁₈ silica gel minicolumn and subsequent measurement of the absorbance of N2N at λ = 508 nm after its elution. The applicable concentration range, the detection and the relative standard were the following: for P4R, from 0.30 to 20.0 mg/L; 0.052 mg/L 1.1%; and for N2N, between 0.020 to 3.0 mg/L 0.003 mg/L and 1.1%. The method was applied to the determination of small amounts of N2N present in P4R in food and cosmetic products. Percentages of recovery between 95 and 105% were obtained in all instances. The method was applied satisfactorily to the determination of the compounds P4R and N2N in samples of sweets and cosmetic products when compared to results offered by a HPLC reference method. Received April 5, 2001. Revision July 25, 2001.     

High-performance liquid chromatographic analysis of cyclizine and its metabolite,norcyclizine in biological fluids using solid phase extraction

Summary A high-performance liquid chromatographic analysis of cyclizine and its metabolite, norcyclizine in biological fluids using protryptiline hydrochloride as internal standard is described. The drug and metabolite were extracted from the relevant biological matrix using a solid-phase extraction procedure combined with a simple phase separation step prior to chromatographic analysis. The separation was achieved on a reversed-phase C₁₈ column (10 μm) using acetonitrile — 0.05 M (pH=3) phosphate buffer (40:60), as the mobile phase with UV detection at 200 nm. Calibration curves were linear over the entire concentration range 5–100 ng/ml for cyclizine in serum and urine and for norcyclizine in urine. Precise quantitative analysis with relative standard deviations of <5 % was achieved.     

固相微萃取和同时蒸馏萃取与气相色谱/质谱法分析芥末膏制品的风味成分

采用固相微萃取和同时蒸馏萃取技术分离芥末膏制品的挥发性成分，用ＧＣ／ＭＳ分析鉴定，对总离子流色谱的峰面积进行归一化定量。共鉴定了２２种化学成分，占总峰面积的９９％以上，其中含硫化合物８种，含氮化物３种，含氧化合物１１种。最主要的成分是异硫氰酸烯丙酯，其次是丙二醇，其他主要成分还有对羟基二叔丁基甲苯、油酸、９－十六烯酸、棕榈酸、５－甲基甲氢噻吩－２酮、二烯丙基二硫化物，异硫氰酸苯乙酯等。比较了各种萃取技术对分析结果的影响，同时蒸馏萃取法不能分离出水溶性成分如丙二醇等，在固相微萃取方法中，聚二甲基硅氧烷纤维头对极性较强的成分的取样效果不理想，聚乙二醇－二乙烯苯纤维头顶空取样的萃取效果最好。     

Developing a robust LC–MS/MS method to quantify Zn‐DTPA,a zinc chelate in human plasma and urine

Quantitation of Zn‐DTPA (zinc diethylenetriamene pentaacetate, a metal chelate) in complex biological matrix is extremely challenging on account of its special physiochemical properties. This study aimed to develop a robust and specific liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for determination of Zn‐DTPA in human plasma and urine. The purified samples were separated on Proteonavi (250 × 4.6 mm, 5 μm; Shiseido, Ginza, Tokyo, Japan) and a C₁₈ guard column. The mobile phase consisted of methanol–2 mm ammonium formate (pH 6.3)–ammonia solution (50:50:0.015, v/v/v), flow rate 0.45 mL/min. The linear concentration ranges of the calibration curves for Zn‐DTPA were 1–100 μg/mL in plasma and 10–2000 μg/mL in urine. The intra‐ and inter‐day precisions for quality control (QC) samples were from 1.8 to 14.6% for Zn‐DTPA and the accuracies for QC samples were from −4.8 to 8.2%. This method was fully validated and successfully applied to the quantitation of Zn‐DTPA in plasma and urine samples of a healthy male volunteer after intravenous infusion administration of Zn‐DTPA. The result showed that the concentration of Zn‐DTPA in urine was about 20 times that in plasma, and Zn‐DTPA was completely (94.7%) excreted through urine in human.     

Stir bar sorptive extraction-gas chromatography-mass spectrometry analysis of tetramethylene disulfotetramine in food: Method development and comparison to solid-phase microextraction

A stir bar sorptive extraction-gas chromatography-mass spectrometry (SBSE-GC-MS) method for the determination of tetramethylene disulfotetramine is presented. The limits of detection (LOD) of the optimized method was 0.2 ng g⁻¹ for extractions from water and 0.3-2.1 ng g⁻¹ for extractions from foods. Recovery was highly matrix dependent (36-130%) and quantification required standard addition calibrations. Standard addition calibration lines had high linearity (R² > 0.97) and replicate extractions had good reproducibility (R.S.D. = 4.4-9.8%). A comparison of the SBSE method and a previously developed headspace (HS)-solid-phase microextraction (SPME) method was performed. Generally, SBSE provided higher sensitivity with decreased analysis time.     

浊点萃取-流动注射电感耦合等离子体原子发射光谱法同时测定水中镉钴铜镍锌

本文提出了浊点萃取-流动注射电感耦合等离子体原子发射光谱（FI—ICP—AES）法同时测定水中镉、钴、铜、镍、锌的新方法。利用5-Br—PADAP将待测金属离子转化为水不溶性的螯合物，并萃取到表面活性剂Triton X-114的浓缩相，以乙醇-硝酸溶液稀释含富集离子的浓缩相，并以FI—ICP-AES法测定。考察了流动注射进样体积、积分时间、萃取体系介质酸度、螯合剂和表面活性剂用量等实验条件的影响。在折衷条件下，镉、钴、铜、镍和锌的浓缩倍率可达18、10、16、10和8，检出限分别为0．7μg／L、1．6μg／L、1．3μg／L、5．7μg／L、3．2μg／L。方法成功应用于自来水、河水和海水中痕量镉、钴、铜、镍和锌的分析。在0．02mg／L和0．10mg／L二个水平进行加入回收试验，回收率在80％与118％之间。     

Fast analysis of catecholamine metabolites MHPG and VMA in human plasma by HPLC with fluorescence detection and a novel SPE procedure

A fast and sensitive high-performance liquid chromatographic method has been developed for the determination in human plasma of MHPG (3-methoxy-4-hydroxyphenylethylenglycol) and VMA (vanillyl mandelic acid), the main metabolites of epinephrine and norepinephrine. Analyses were carried out at 325 nm while exciting at 285 nm on a reversed-phase column (Atlantis C18, 150 mm × 4.6 mm I.D., 5 μm) using a mobile phase composed of 2% methanol and 98% aqueous citrate buffer at pH 3.0. A careful solid-phase extraction procedure, based on mixed-mode reversed-phase - strong anion exchange Oasis cartridges (MAX, 30 mg, 1 mL), was developed for the pre-treatment of plasma samples. Extraction yields were satisfactory, always higher than 90%. Calibration curves were linear over the 0.2-40.0 ng mL⁻¹ concentration range for MHPG and over the 0.5-40.0 ng mL⁻¹ concentration range for VMA. The method was successfully applied to plasma samples of former drug users undergoing detoxification therapy and subjects “at risk” of developing drug addiction.     

Novel light-fluorous TEMPO reagents and their application in oxidation reactions

The synthesis of two light-fluorous TEMPO derivatives is reported, along with their application in oxidation reactions.     

Adsorption behaviour of cadmium on L-methionine immobilized on controlled pore glass

The adsorption behaviour of Cd onto the relative non-polar L-methionine was studied. To this end, L-met was immobilized on controlled pore glass (CPG), incorporated in a microcolumn and inserted in a flow injection system for Cd preconcentration from aqueous solutions. Binding constant of the system was calculated and it turned to be of 1.99, with sites capacity of n = 3.12. The ratio of Cd moles bound to L-met moles was calculated and it was 0.03:1 at pH 9.0. On-line breakthrough curves were used to study the effect of pH, analyte concentration and influent flow rate on Cd retention. A complementary pH study was added with a titration curve. Transient peak areas revealed that Cd stripping from the column occurred instantaneously. The system achieves an enrichment factor of 130, reaching a detection limit of 0.63 ng L^{− 1} when 10 mL of the solution were passed through the column. The method was successfully applied to Cd determination in the standard reference material (SRM), QC METAL LL2 metals in natural water, as a validation study.