豆类中4种嘌呤的高效液相色谱测定法

目的:建立豆类中嘌呤含量测定的高效液相色谱法(HPLC)。方法:采用10%(v/v)高氯酸溶液在100℃水浴中水解样品60 min,样品液调节pH值,过滤后,进行色谱分析。色谱柱为Agilent ZORBAX Eclipse XDB-C18(250×4.6 mm,5μm),柱温25℃,流动相为0.007 mol/L KH2PO4(pH=4.0),流速1.0 ml/min,紫外检测器254 nm处检测,进样量为20μl。结果:在0.1 mg/L～25 mg/L的浓度范围内,各嘌呤的响应峰面积与浓度呈良好线性相关,r>0.9997,相对标准偏差<8.74%,样品加标回收率为85.9%～104.3%。结论:该方法测定豆类中嘌呤含量,具有简便快速、结果准确可靠、重现性好等优点。不同豆类的嘌呤总含量在58.2～158.1 mg/100 g之间。     

固相萃取高效液相色谱法检测水中二苯胺残留量

目的:建立固相萃取高效液相色谱法测定水中二苯胺残留量的方法。方法:样品经固相萃取后进行高效液相色谱测定。色谱柱为SUPELCO Discovery C185μm 250×4.6 mm,流动相为:甲醇:0.02 mol/L NH4AC(pH=4.2)=70:30(V/V),流速为0.8 ml/min,二极管阵列检测器,检测波长为280 nm。结果:该方法的线性范围为:0.050～10.0μg/ml;标准曲线线性良好,其回归方程及相关系数r为Y=348.4X-3.5,r=0.99999。检出限为:0.60μg/L;回收率在99%～103%之间,相对标准偏差小于2.0%。结论:该方法操作简便、快捷,是水中二苯胺残留量的快速而准确的检测方法。     

中国常见植物性食品中嘌呤的含量

目的应用HPLC测定中国常见植物性食品中嘌呤的含量。方法采用Waters Atlantis T3柱(4.6mm×250mm×5μm),以10.0mmol/L甲酸铵(pH3.6)-甲醇(99∶1,V/V)为流动相,流速:1.0ml/min,柱温:30℃,检测波长:254nm。结果不同种类植物性食品中嘌呤含量有明显差别。干菌类和干豆类及制品中嘌呤含量普遍高于其他食品,蔬菜类及制品和水果类及制品中嘌呤含量普遍较低。总体上呈现出干菌藻类>干豆类及制品>鲜菌藻类>坚果、种子类>谷类及制品>蔬菜类及制品>薯类、淀粉及制品>水果类及制品。结论植物性食品中干菌藻类和干豆类及制品中嘌呤含量较高,其他种类食品嘌呤含量较低,不同种类植物性食品中嘌呤含量差异较大。     

中国常见动物性食品中嘌呤的含量

目的应用高效液相色谱法测定我国常见动物性食品中嘌呤的含量。方法采用WatersAtlantisT3色谱柱(4.6mm×250.0mm×5.0μm),以10.0mmol/L甲酸铵(pH3.6)和甲醇(99:1)为流动相,流速:1.0 ml/min,柱温:30℃,检测波长:254nm。结果不同种类动物性食品中嘌呤的含量有明显差别。内脏(如肝脏)和鱼虾蟹贝类中最高,肉和肉制品次之,血液和汤类等最低。畜肉中,猪肉最高,畜类内脏中,猪肝最高;禽肉中,鸡肉最高,禽类内脏中,鸭肝最高;鱼虾蟹贝类食品中虾类最高。结论动物性食品中嘌呤的含量很高,不同种类食品差异较大。     

高效液相色谱法同时测定血浆中S-腺苷甲硫氨酸和S-腺苷同型半胱氨酸

目的建立同时测定血浆中S-腺苷甲硫氨酸(SAM)和S-腺苷同型半胱氨酸(SAH)的高效液相色谱分析方法,并对正常人血浆中的含量进行测定。方法样品用400g/L三氯乙酸处理,离心取上清液过膜,以50mmol/L NaH2PO4缓冲液(pH4.38)、庚烷磺酸钠和甲醇为流动相,选用Venusil MP-C18(4.6mm×250mm,5μm)色谱柱进行色谱分离,流速为1.0ml/min,柱温30℃,紫外检测波长254nm。结果 SAM和SAH在相应检测浓度范围内与其响应值呈良好的线性关系(r>0.9999);方法回收率在94.14%～102.44%,相对标准偏差在1.00%～8.10%。正常人血浆中SAM和SAH的含量分别为0.032～0.080mg/L和0.004～0.010mg/L。结论该方法用于血浆中SAM和SAH的检测简便快速,准确可靠。     

RP-HPLC内标法测定血浆中沙利度胺的浓度

目的建立高效液相色谱法测定人血浆中沙利度胺的浓度。方法采用液-液萃取方法,用乙酸乙酯提取血浆中沙利度胺,选用非那西丁为内标,色谱柱为Waters Atlantis T3 C18(4.6 mm×150 mm,5μm)反相柱,流动相:乙腈-25 mmol/L KH2PO4缓冲液(PH3.5)(25∶75);沙利度胺的检测波长为220 nm,非那西丁的检测波长为248 nm;流速为1 ml/min。结果本方法的线性范围为0.05～20μg/ml,r2=0.999 0,沙利度胺保留时间7.8 min,平均方法回收率为(95.3±8.2)%(n=15),日内RSD≤4.5%,日间≤7.8%。准确度在88.1%～95.6%之间。沙利度胺的最低检测浓度为0.05μg/ml。结论本方法灵敏、准确、选择性强,适用于临床血药浓度监测和人体药代动力学研究。     

高效液相色谱法测定保健食品中的吡啶甲酸铬

目的测定保健食品中的功效成分吡啶甲酸铬。方法采用高效液相色谱法,色谱柱:ZorbaxSBC18反相分离柱,三元流动相:甲醇∶乙腈∶0.05mol/LNaH2PO4(H3PO4调节pH=4)=10∶5∶85溶液;检测波长为254nm;流速为0.8ml/min;柱温为室温;进样量:10μl。结果吡啶甲酸铬在2.48~124.00μg/ml范围呈良好线性,最小检出限为0.015μg,标准溶液测定精密度RSD<0.16%,胶囊和片剂平均回收率分别为94.7%和99.4%。结论方法具有高的分离效果、准确度、精密度和灵敏度,能对保健食品中添加的功效成分吡啶甲酸铬进行准确的定量测定。     

超高效液相色谱法测定中式菜肴中4种嘌呤

目的 建立超高效液相色谱测定中式菜肴中黄嘌呤、次黄嘌呤、鸟嘌呤和腺嘌呤的方法，了解北京常见中式菜肴中嘌呤的分布情况。方法 菜肴样品经4%高氯酸水溶液水解，用KOH溶液调节pH至8.4,经过滤后采用Shim-pack GIST C₁₈-AQ色谱柱(2.1 mm×100 mm, 1.9μm)分离，254 nm波长下进行测定。结果 4种嘌呤的线性范围为1～100μg/mL,相关系数(r²)均大于0.999,在高、中、低3个水平加标回收率为87.5%～95.9%,相对标准偏差<6%(n=6)。方法检出限为0.19～0.36μg/g,定量限为0.62～1.20μg/g。80道中式菜肴中4种嘌呤的含量为1.43～237.32 mg/100 g,黄嘌呤含量最低，鸟嘌呤、腺嘌呤、次黄嘌呤含量接近，分布特征不同。结论 本方法简便稳定，准确灵敏，适用于中式菜肴中4种嘌呤的测定。     

亲水作用色谱法测定食品及烟用香料中的硫脲

目的:建立食品及烟用香料中硫脲含量测定的高效亲水作用色谱方法。方法:采用Venusil HILIC色谱柱,以乙腈/水=97/3(V/V)为流动相,检测波长为236 nm,流速为1 ml/min。在此条件下色谱峰峰形良好。结果:在0.1μg/ml～10μg/ml内,其浓度与峰面积具有良好的线性关系(相关系数为0.9999),最低检出限为0.1 ng,标准偏差为1.19%～2.89%,回收率为98.3%～103.2%。结论:该法简单,分析时间短,可快速准确的测定食品中硫脲的含量。     

食品、多维片和饮料中12种维生素的高效液相色谱法同时测定

目的建立食品、多维片和饮料中水溶性维生素C、B1,B2,B6,B12,烟酸、烟酰胺、叶酸和脂溶性维生素A、D3、E、K1的反相高效液相色谱同时测定方法。方法样品中水溶性维生素经0.01mol/LHCl超声提取,脂溶性维生素经皂化法提取。饮品直接过滤后测定。色谱条件:色谱柱为C18柱,流动相为0.05mol/LKH2PO4溶液(pH6.0)-甲醇,梯度洗脱流速1.1~1.5ml/min;柱温40℃。结果 12种维生素标准曲线的线性范围:VC为0～5μg,烟酸为0～0.5μg,其余均为0～1μg;相关系数均大于0.996;相对标准偏差均小于5.0%;方法检出限为0.073～0.193μg/ml;加标回收率为75.5%～118.0%。结论所建立的方法快速、简便、灵敏、准确,应用于复合维生素片、米粉、饮料中12种维生素的同时分析,取得了较好结果。     

Differences in uricogenic effects of dietary purine bases, nucleosides and nucleotides in rats

The uricogenic effects of dietary free purines (adenine, guanine, hypoxanthine and xanthine), their nucleosides (adenosine, monophosphate, guanosine monophosphate and inosine monophosphate) were studied in rats. Casein-based diets (20% protein) supplemented with 30 mmol/kg diet of each of the free purine base, nucleoside or nucleotide were fed to male Sprague-Dawley rats (100 +/- 5 g) for 14 d. Addition of adenine resulted in less weight gain than in controls, greater kidney weight, greater urine volume and higher levels of blood urea nitrogen, serum uric acid, creatinine and allantoin but lower urinary levels of allantoin, uric acid and creatinine. The adenine diet also caused nephropathy characterized by nephromegaly and deposition of crystals. A microscopic examination of the kidneys revealed deposition of crystals mainly in the lumen of convoluted tubules of the cortex. Feeding of diets containing other purine bases, nucleosides and nucleotides had no adverse effects on kidney weight or structure, urine volume, serum uric acid or creatinine. Urinary allantoin excretion, however, was greater in rats fed hypoxanthine, xanthine, nucleoside and nucleotide diets than in control rats. Adenine produced adverse effects only when fed in the free form and not when fed as the nucleoside or nucleotide, suggesting a metabolic significance for free adenine in predicting hyperuricemic effects of foods.     

Influence of purine intake on uric acid excretion in infants fed soy infant formulas

OBJECTIVE: These studies tested the hypothesis that increasing intake of purines, delivered as RNA from soy protein-based infant formula, would increase urinary uric acid excretion in infants. METHODS: Study One examined the influence of feeding on serum uric acid in a total of 178 infants from four separate trials with infants fed commercial and experimental soy-based and milk-based infant formulas or human milk. Studies Two and Three compared the effect of a standard purine soy formula (STD Purine; 180 mg purines/L from RNA) and a reduced purine soy formula (Reduced Purine; 65 mg purines/L; 26 mg/L from RNA and 39 mg/L from ribonucleotides) on urinary uric acid excretion in infants. In Study Two, 11 infants ranging in age from 16 to 128 days of age were fed both formulas in a random crossover design. Complete 72-hour urine collections were done at the end of each 11-day feeding period. Urinary uric acid excretion was expressed as mmol/day. In Study Three, 33 infants were enrolled before eight days of age and randomized to one of the formulas one week later. Spot urine samples were collected at 28 and/or 56 days of age and urinary uric acid concentration was expressed as mmol/mmol creatinine. RESULTS: In Study One, each of the feedings resulted in mean serum uric acid levels within normal reference ranges. Soy formula led to higher serum uric acid levels than human milk, and human milk to levels indistinguishable from cow milk-based formulas. In Study Two, infants excreted significantly more uric acid in the urine when fed the STD Purine formula compared to the Reduced Purine formula (0.86+/-.04 vs. 0.57+/-.04 mmol/d) (p = 0.006). In Study Three, infants fed the STD Purine formula had a significantly higher concentration of uric acid in their urine compared to those fed the Reduced Purine formula (2.1+/-0.2 vs. 1.4+/-0.1 mmol uric acid/mmol creatinine) (p = 0.0001). CONCLUSION: These data indicate that healthy infants can digest RNA and subsequently absorb the liberated purine ribonucleotides as determined by urinary uric acid concentration.     

高效液相色谱法测定保健食品中阿魏酸含量的方法研究

目的:建立保健食品中阿魏酸的高效液相色谱测定方法。方法:采用WATERS Xterra RP18(4.6×250 mm,5μm)色谱柱分离;流动相为乙腈:0.5%冰醋酸=28:72(v/v);流速1.00 ml/min;2487紫外检测器322 nm测定。结果:阿魏酸在0.005μg/ml～80μg/ml时,浓度与峰面积呈良好的线形关系(r=0.9999),检出限为5.0μg/L,加标回收率在98.0%～100.8%之间,相对标准偏差RSD在1.10%～1.81%之间。结论:该方法简便、快速、准确,适用于保健食品中阿魏酸含量的测定。     

Urinary excretion of purine derivatives as an index of microbial protein synthesis in the camel (Camelus dromedarius)

Five experiments were carried out to extend knowledge of purine metabolism in the camel (Camelus dromedarius) and to establish a model to enable microbial protein outflow from the forestomachs to be estimated from the urinary excretion of purine derivatives (PD; i.e. xanthine, hypoxanthine, uric acid, allantoin). In experiment 1, four camels were fasted for five consecutive days to enable endogenous PD excretion in urine to be determined. Total PD excretion decreased during the fasting period to 267 (SE 41.5) micromol/kg body weight (W)0.75 per d. Allantoin and xanthine + hypoxanthine were consistently 86 and 6.1 % of total urinary PD during this period but uric acid increased from 3.6 % to 7.4 %. Xanthine oxidase activity in tissues (experiment 2) was (micromol/min per g fresh tissue) 0.038 in liver and 0.005 in gut mucosa but was not detected in plasma. In experiment 3, the duodenal supply of yeast containing exogenous purines produced a linear increase in urinary PD excretion rate with the slope indicating that 0.63 was excreted in urine. After taking account of endogenous PD excretion, the relationship can be used to predict purine outflow from the rumen. From the latter prediction, and also the purine:protein ratio in bacteria determined in experiment 5, we predicted the net microbial outflow from the rumen. In experiment 4, with increasing food intake, the rate of PD excretion in the urine increased linearly by about 11.1 mmol PD/kg digestible organic matter intake (DOMI), equivalent to 95 g microbial protein/kg DOMI.     

油脂中柠檬酸的高效液相色谱测定法

目的采用高效液相色谱法测定油脂中柠檬酸的含量。方法选用Aglient TC-C18柱(250 mm×4.6 mm×5μm),流动相为0.05 mol/L KH2PO4溶液(pH=2.40),流速为1.5 ml/min,柱温为35℃,检测波长为210 nm,外标法定量。结果柠檬酸线性范围为10.0～200 mg/L,r=0.999 8,回收率为91.1%～105.0%,变异系数为1.7～5.4%。结论该方法简便、准确、稳定、可靠,可用于油脂中柠檬酸的质量控制。