Determination of isosorbide dinitrate in pharmaceutical products by HPLC

A high-performance liquid chromatographic (HPLC) assay for isosorbide dinitrate in pharmaceutical formulations is described. The method employs a reversed-phase C18 column with a mobile phase containing methanol/water/acetate buffer and is specific for isosorbide dinitrate with respect to its 2- and 5-mononitrate degradation products and other organic polynitrate esters. The method is applicable to the analysis of the diluted bulk drug and dosage forms, including sublingual, oral, chewable, and timed-release preparations.     

Determination of DEHP in blood products stored in plastic bags by HPLC

Summary High-performance liquid chromatography (HPLC) was used for the routine monitoring of the plasticizers di(2-ethylhexyl) phthalate (DEHP) and tri(2-ethylhexyl) trimellitate (TOTM), in blood products. It allows easy sample clean-up, solvent extraction using Celite 545 sorbent, good recoveries and opportunity to inject large number of samples without effect on column performance. The plasticizer levels were investigated in two types of poly(vinyl chloride) (PVC) bags containing whole blood plasma, platelet concentrates (PCs) during blood taking and storage.     

Determination of phospholipids in dairy products by SPE/HPLC/ELSD

The aim of this work was to evaluate the performance of different methods for both milk lipid extraction and phospholipids separation. As far as the lipid extraction procedure is concerned, the Folch method showed a higher phospholipid recovery with respect to the Rose-Gottlieb method. Different SPE cartridges and solvent phases were tested to carry out the separation of phospholipids from fat. The yield of extraction was evaluated by isolating phospholipids from both milk fat and synthetic fat; Standard Addition Method was applied as well. The isolation of the phospholipids by SPE silica column and subsequent analysis by HPLC/ELSD was shown to be an accurate and reproducible analytical method for the determination of phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidylcholine and sphingomyelin in milk fat extracted by Folch method.     

Determination of potential degradation products of piroxicam by HPTLC densiometry and HPLC

Summary HPTLC densitometry and HPLC are considered for the simultaneous determination of the degradation products of piroxicam (2-aminopyridine, DP-I and DP-II). The substances were separated on silica gel with fluorescence indicator in ethylacetate — toluene — diethylamine (10∶10∶5) and toluene — absolute ethanol — glacial acetic acid (8∶1.2∶0.5) systems. The measuring absorbance (detection of reflectance) of the separated substances was carried out “in situ” at 296 nm using 4-level calibration (external standard, nonlinear regresson function) in the concentration range 600–1200 ng 2-aminopyridine/spot and 300–600 ng DP-I and DP-II/spot. The HPLC method was carried out using RP-8 stationary phase and methanol + phosphate-citrate buffer, pH 3 mobile phase with addition of sodium pentanesulfonate (40+60, v/v). 2-aminopyridine wass detected at 300 nm, DP-I at 280 nm and DP-II at 248 nm. The concentration range for 2-aminopyridine is 2–40 μg/ml, for DP-I and DP-II 2–20 μg/ml (for an injection volume of 10 μl). The results were evaluated by linear regression analysis.     

Determination of aflatoxins in peanut products using reverse phase HPLC

A high performance liquid chromatographic (HPLC) method is described for the determination of the four major aflatoxins, B1, B2, G1 and G2, in peanut products. The aflatoxins are extracted by adapting a procedure developed by Pons (1) at the SRRC, USDA, and quantitated utilizing a new 5 mum reverse-phase column with NaCl/acetontrile/methanol mobile phase (3 + 1 + 1). The 5 mum column achieved baseline resolution of each of the four aflatoxins. Retention times and peak heights were reproducible. The procedure was successfully applied to several types of peanut products and was applicable to both roasted and unroasted peanuts, which is a decided advantage over the current CB and BF extraction methods. Additionally, it can be used for sweetened peanut matrixes with no interferences in the chromatography. The total time required for sample preparation and aflatoxin determination is less than 1.5 hours.     

Determination of N-nitrosodimethylamine in fish products using gas chromatography with nitrogen-phosphorus detection

A simple and rapid gas chromatographic method for the determination of N-nitrosodimethylamine (NDMA) in fish products is described. NDMA is extracted from a dried sample with methylene chloride, mixed with n-hexane and passed through a silica gel column. NDMA adsorbed on silica gel is eluted with methylene chloride-diethyl ether (7:3) and the eluate is passed through a Sep-Pak alumina A cartridge column, on which NDMA is adsorbed. NDMA is eluted from the cartridge with diethyl ether-methanol (2:1) and the solution is injected into a gas chromatograph with nitrogen-phosphorus detection. This method does not use solvent evaporation and concentration in the clean-up procedure, which eliminates the loss of volatile NDMA and artifactual formation of NDMA in the analytical procedure. The detection limit is 0.5-1 micrograms/kg and recoveries from salted pollack roe spiked at 40 and 4 micrograms/kg were 96.7% [relative standard deviation (R.S.D.) 3.6%] and 85.0% (R.S.D. 6.8%) respectively.     

Determination of trace amounts of morpholine and its thermal degradation products in boiler water by HPLC

Summary Morpholine and its amine-type thermal degradation products present in boiler feed water and steam condensate were derivatised with N-succinimidyl-p-nitrophenylacetate. These pre-column derivatives were determined by high-performance liquid chromatography with UV detection at 280 nm. The analytical column was Supelco-sil-ODS with an isocratic mobile phase. Morpholine and its breakdown products were monitored in the range 0.01–10 g ml^–1 with a relative standard deviation of 0.4–3.0%. Chromatographic analysis of boiler feed water and steam condensate samples collected from a boiler servicing a petroleum refinery is described.     

Determination of flavonoids and stilbenes in red wine and related biological products by HPLC and HPLC-ESI-MS-MS

To investigate probable health benefits of flavonoids and stilbenes in red wine a new reversed-phase (RP) high-performance liquid-chromatographic (HPLC) method with enhanced separation efficiency and improved selectivity, sensitivity, and speed has been established for determination of the flavonoids quercetin, myricetin and kaempferol and the stilbenes cis- and trans-resveratrol, in a single run . UV-absorbance, fluorescence (FLD), and mass-spectrometric (MS) detection were also evaluated. UV-absorbance detection at 320 nm for stilbenes and 377 nm for flavonoids enables their determination up to the nanogram range with a linearity of R2>0.9999 (linear range 50 ng mL(-1)-50 microg mL(-1)). Calculated values of average recoveries were between 95 and 105% for all analytes. For resveratrol, fluorescence detection was highly selective and twice as sensitive as UV detection, and linearity was satisfactory (R2>0.9996; linear range see UV detection). For the detection of the hydrophilic glycosidic compounds piceid and rutin, which are coeluted with other hydrophilic ingredients, the validated RP HPLC system was coupled to a quadrupole ion-trap mass-spectrometer (MS) via an electrospray interface (ESI) with 25% ammonia solution as sheath liquid. MS detection was, highly linear (R2>0.9878; linear range 50 ng mL(-1)-50 microg mL(-1)) for all investigated analytes and the limits of detection were in the low nanogram range. Compared with UV detection MS detection resulted in a 200% increase in signal intensity for myricetin and 400% increases for quercetin and kaempferol, but equal signal intensity for resveratrol. Calculated values of average recoveries were 102% for myricetin and 79% for piceid. Collision induced dissociation (CID) was also used to obtain characteristic fragmentation fingerprints to facilitate qualitative and quantitative analysis even in complex matrices. Finally, this hyphenated HPLC-ESI-MS method was highly suitable and an essential improvement compared with UV- and fluorescence detection.     

快速溶剂萃取-超高效液相色谱法分析鱼肉中喹乙醇

以甲醇为溶剂,采用ASE快速、高压萃取鱼肉中喹乙醇,并实施了自动在线净化过滤,色谱分析采用了乙醇(色谱级)为流动相,超快速液相色谱法进行分析。喹乙醇的标准工作溶液的线性回归方程为y=0.0358x+0.0019,相关系数r=0.9999,线性范围为0.1～2.0μg/mL,方法检出限(以信噪比(S/N=3)计算)为5.0μg/kg,样品加标回收率平均值(n=3)为88%,同时对6个平行样进行精密度试验,保留时间与峰面积的RSD值分别为0.21%和2.0%,重现性较好。方法可以用来快速分析鱼肉等样品中的喹乙醇。     

新药乌拉地尔含量的高效液相色谱法测定

用高效液相色谱法测定乌拉地尔（urapidil)的含量。采用PhenomenexLUNA C18柱;1％（φ）冰醋酸溶液－甲醇（体积比50：50）为流动相;检测波长为268nm;外标法定量测定,结果显示样品质量浓度在10－200nm/L范围内与峰面积呈良好线性关系,相关系数为0．9999（n-5);平均加标回收率为99．8％。该法操作快捷,重复性好,结果准确可靠,可用于乌拉地尔的质量控制。     

高效液相色谱法测定苯并三氮唑

提出了高效液相色谱法测定苯并三氮唑产品以及工业循环冷却水中苯并三氮唑含量的方法。色谱分离采用Kromasil C18(4.6 mm×250 mm,5μm)色谱柱,以乙腈-水(25+75)为流动相,流量为1.0 mL.min-1,检测波长为260 nm。苯并三氮唑的质量浓度在3.84~76.8 mg.L-1范围内与峰面积呈线性关系,平均回收率为96.4%。     

高效液相色谱法测定氮丙啶

提出了一种测定氮丙啶的高效液相色谱分析方法。将自制氮丙啶单体与福林试剂(1,2-萘醌-4-磺酸钠盐)反应得到衍生物,通过NMR和IR表征验证衍生物结构。衍生物在Agilent ODB C18色谱柱(250mm×4.6mm,5μm)上分离,以乙腈-0.04mol·L-1磷酸氢二钠混合溶液为流动相进行梯度洗脱,检测波长为258nm。氮丙啶的线性范围为1.00~20.0mg·L-1,检出限(3S/N)为0.05mg·L-1,测定值的相对标准偏差(n=6)小于2%。     

高效液相色谱法测定非诺贝特含量

以甲醇－水（９５：５,Ｖ／Ｖ）为流动相,用ＯＤＳ柱以高效液相色谱法测定非诺贝特含量。紫外检测波长为２８６ｎｍ。非诺贝特在浓度为０．０４－０．２０ｇ／Ｌ间线线性关系良好。重复进样ＲＳＤ＝０．１４％,最低检出浓度为０．１０ｍｇ／Ｌ,平均回收率为９９．６６％。     

氧氟沙星的 HPLC法测定

采用ＨＰＬ法测定了氧氟沙星的含量,方法先进,结果可靠。可用于氧氟沙星软膏的质量控制。     

Determination of N-acetyl-l-glutamine in urine by HPLC

Summary The determination of N-acetyl-l-glutamine (AC-GLN) in urine of rats after derivatization with xanthydrol by HPLC is described. The urine samples were collected from two groups of rats, one group fed normal nutrition, the other treated with AC-GLN. About 5 mM/l AC-GLN was detected in urine of untreated animals, whereas the excretion of the other group was in the range of 50 mM/l corresponding to about 50 wt.-% of the given AC-GLN.

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Bestimmung von N-Acetyl-l-glutamin in Urin mit Hilfe der HPLC

Zusammenfassung Ein Verfahren wird beschrieben zur HPLC-Bestimmung von N-Acetyl-l-glutamin (AC-GLN) in Rattenurin nach Derivatisierung mit Xanthydrol. Die Urinproben wurden von zwei Gruppen von Ratten gesammelt, einer Gruppe mit normaler Ernährung und einer Gruppe mit AC-GLN-Behandlung. Im Urin der unbehandelten Tiere wurden 5 mM/l AC-GLN nachgewiesen; die Ausscheidung bei der anderen Gruppe lag im Bereich von 50 mM/l, entsprechend etwa 50 Gew.% des eingesetzten AC-GLN.

     

Determination of n-acetylmuramoyl-l-alanyl-d-isoglutamine in liposomes by HPLC

A method using reversed-phase high-pressure liquid chromatography (with spectrometric detection at 218nm) is described for the determination in new pharmaceutical preparations (liposomes) of a new immunostimulating agent (N-acetylmuramoyl-l-alanyl-d-isoglutamine). Separation was achieved with a mu-bondapak column and phosphate buffer (pH 2.5)-methanol mixture (93:7 v/v) as eluent, at a flow-rate of 2 ml min . Sodium acetate was used as an internal standard. The detector response at 218 nm was linear in the range 10-170 mug ml . The method is simple and accurate.     

饲料中三甲氧苄胺嘧啶的HPLC检测

用二氯甲烷-1 mol/L醋酸钠溶液混合提取饲料中的三甲氧苄胺嘧啶,经离心分层后,取下层提取液用氮气吹干,1%(体积分数)冰醋酸复溶后用正己烷洗涤除脂两次,用液相色谱/紫外检测法测定,检测波长为270 nm.结果表明,该方法平均回收率为80%～87%,相对标准偏差为3.0%～8.5%(n=4),配合饲料、浓缩饲料和预混合饲料中的检出限依次为1.2、2.0和0.9 μg/g;定量下限依次为2.3、4.3和2.3μg/g.     

高效液相色谱法测定烟草中的多酚类物质

研究了用高效液相色谱法测定烟草样品中多酚的方法.烟草样品中的多酚部分提取液用固相萃取小柱预分离,以C18为固定相,甲醇为流动相,进行梯度洗脱,烟草中主要的多酚物质均达到基线分离;利用外标法进行定量分析,标准回收率为94%～105%,相对标准偏差为1.28%～1.49%.用该方法测定了一些烟草样品中的植物多酚.     

高效液相色谱法测定尿液中儿茶酚胺类物质

本文报道用高效液相色谱法(HPLC)分离,荧光检测器检测儿茶酚胺含量的新方法。该法可同时分离测定去甲肾上腺素(NE)、肾上腺素(E)和多巴胺(DA)三种组分,三种组分的浓度与其峰面积均呈良好的线性关系。方法灵敏度高,选择性好,测定结果令人满意,可在临床推广应用。